Annual/Termination Reports:

[02/07/2008] [02/20/2009] [03/01/2010] [11/08/2011] [12/23/2011]

Report Information

Participants

Howard Schwartz, Colorado State University(Howard.Schwartz@ColoState.EDU); Mike Bartolo, Colorado State University; John Lambert, JL Computing (web site specialist); T.X. Liu, Texas A&M; Hanu Pappu, Washington State University; Stuart Reitz, USDA-ARS, Tallahassee;Mike Edwards, DuPont Crop Protection;
Krishna S. Mohan, University of Idaho; Christy Hoepting, Cornell University; Chris Cramer, New Mexico State University; Dan Drost, Utah State University;
Brian Nault, Cornell University; Lynn Jensen, Oregon State University; Lindsey du Toit, Washington State University; Morgan Reeder, Utah; Wade Norman, Utah;
Les Watada, Logan Zenner Seed Company; Larry Duell, Champion Seed Company; Tony Shelton, Cornell University; Robert T. Sakata, Colorado Onion Association President and producer; Wayne Minninger National Onion Association Executive Vice President; Laura Quackenbush, Colorado Department of Agriculture;

Brief Summary of Minutes

The annual meeting of W 1008 - Onion IYSV & Thrips was held January 15-16, 2008 at the La Quinta Inn & Suites, Denver, Colorado.

Howard Schwartz, Committee Chair, opened the meeting with introductions and welcome from Lee Sommers (Administrative Liaison) who could not attend due to a conflict. Howard reviewed the history of the W 1008 committee (WDC7, WTemp2081) with its formal approval in October of 2007. Howard noted that the number of objectives in the project plan was reduced from 5 to 3, and asked that participants update their NIMMS profiles to reflect these 3 objectives. Contact your AES Director regarding travel funds. The committee also helps justify allocation of time and effort by experiment stations to onion research. Members were urged to invite colleagues to join the W1008 Committee, and contact list provided by Howard in the packet of handouts and other information. One of the benefits of this type of regional committee is that it raises the profile of onion thrips/IYSV problems to Congress and the USDA.

I. Wayne Minninger NOA report - Tried the last two years to get funds for IYSV/Thrips research initiative (3 new USDA-ARS positions, research grants) at $7 million over 5 years. Finally got $250,000 in language but was axed at the last minute. Lots of unfinished business, i.e., $ 22 billion of unfunded programs in Senate version of the Farm Bill. Conferencing going on now and does have specialty crop research money. When requests come for support in the form of letters, personal contacts with elected officials are very helpful. Wayne suggested that the past initiative just be updated and Wayne will resubmit. NOA is supportive of this program. With too many onions it's tough to sell the need of the initiative, but Wayne would appreciate any support that we can give. He also mentioned that the data and photographs (of rapid disease progression) that Lindsey tu Doit presented today would be helpful to demonstrate impacts.

NOA annual meetings schedule is: Summer Pasco July 23-26, 2008; Winter 08 in Florida; Summer July 09 in Montreal; Winter of 09 in San Antonio.

Howard Schwartz briefly reviewed the request for initiative where the $ would go to ARS to support three staff and some pass through monies for targeted research projects. Ideas on how to update the proposal would be welcome.

II. Reports from Onion Organizations
A. COA: Robert T. Sakata - Colorado saw moderate IYSV but extreme thrips pressure.

B. Utah: Wade Norman - Utah didn't have too much thrips pressure or IYSV pressure.

(Note: http://www.allium.net/index.htm is good resource, coordinated by Howard Schwartz. Howard asked for any relevant articles that could be posted on the website.)

III. Report from International Allium Conference, held in the Netherlands in Fall 2007. Lynn Jensen was disappointed because it was mainly USA report. New Zealand research with gene research on pungency; maybe this can lead to transgenic work for thrips resistance. Krishna said that he has talked with researchers in Netherlands, they don't have any IYSV problems. Wayne Mininger said that because Europe is north of the U.S., they don't see it. Lynn noted that it is present in Mediterranean countries but has not received much research attention. So overall it was disappointing conference in reference to IYSV research. With upcoming NARC meeting (Savannah, GA in December of 2008), should they have a special session on IYSV? The committee indicated that it would be a good idea. The executive committee would follow up with the NARC organizing committee to see if a half day session dealing with thrips/IYSV could be included in the 2008 program, and if the W1008 could coordinate their annual meeting with the NARC meeting.

Election of a new Secretary - Cristy Hoepting, New York, was unanimously elected. She will assume those duties at the next meeting when secretary Stuart Reitz succeeds Chris Cramer as Vice-Chair who succeeds Howard Schwartz as Chair of the W1008 Committee.

Link next W1008 meeting with the next NARC. Dec 11-13, 2008 in Savannah, GA: Moved and seconded. The committee will work with NARC to combine, and request 1/2 day for the W-1008

Don't need to submit a formal progress report this year, but will need to by next year.

Look at milestones for proposal and need to work towards those and the 3 objectives.

Insecticide dialog Ad Hoc committee was formed (potential members could include Lynn Jensen, Brian Nault, Whitney Cranshaw, Mike Edwards, Charlie Hicks, Pete Forster, Gordon Hankins, Paul Ogg) and Howard will coordinate.

Need to submit minutes to Lee Sommers and to other participants; needs to be done within 60 days. Howard and Stuart will draft the minutes; Robert Sakata later shared his detailed notes.

Hanu made motion to express the group's appreciation for all of the effort of Howard Schwartz to organize the W1008 Committee and to help the committee members assist the onion industry with these important pest issues. The motion was passed unanimously.

The meeting was adjourned by Howard Schwartz at 1:30 PM.

Accomplishments

The project was initiated on October 1, 2007. A summary of research activities is attached to the meeting minutes.

Publications

Impact Statements

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Report Information

Participants

*Howard Schwartz, Colorado State University, Ft. Collins, CO;*Christy Hoepting, Cornell University, Albion, NY;*Chris Cramer, New Mexico State University, Las Cruces, NM;*Hanu Pappu, Washington State University, Pullman, WA;*Stuart Reitz, USDA-ARS, Tallahassee, FL;*Krishna S. Mohan, University of Idaho, Parma, ID;*Dan Drost, Utah State University, Logan, UT;*Brian Nault, Cornell University, NYSAES, Geneva, NY;*Lynn Jensen, Oregon State University, Ontario, OR;*Clint Shock, Oregon State, Ontario, OR;*Ron Gitaitis, University of Georgia, Tifton, GA;*Steve Beer, Cornell University, Ithaca, NY;*Mike Bartolo, Colorado State University, Rocky Ford, CO;*Kurt Volker, TKI Nova Source Yakima, WA;Robert T. Sakata, Sakata Farms, Brighton, CO;Kerrick Bauman, Connel, WA;Bill Dean River Point Farms, Irrigon, OR;George Boyhan, University of Georgia, Statesboro, GA;Rajagopalbabu Srinivasan, University of Georgia, Tifton, CO;Mike Thornton, University of Idaho, Parma, ID;Ram Sampangi, University of Idaho, Parma, ID;Erik Feibert, Oregon State University, Ontario, OR;Mary Ruth McDonald, University of Guelph, Guelph, ON;Peter Rogers, Nunhems USA, Brooks, OR;Rick Watson, Nunhems USA, Brooks, OR;Charlie Hicks, Bayer CropScience: Livermore, CO;Stephen Ogden, Market Access Solutionz, Wellington, NZ;Cynthia Hsu, Cornell University NYSAES, Geneva, NY;Charles Boateng, Colorado State University;Stephanie Szostek, Colorado State University;Anitha Chitturi , University of Georgia;Stormy Sparks, University of Georgia;Carroll Johnson, USDA-ARS, Tifton, GA

Brief Summary of Minutes

The annual meeting of W 1008 - Onion IYSV & Thrips was held December 10, 2008, in conjunction with the National Allium Research Conference, at the Riverfront Marriott Hotel, Savannah, Georgia.

George Boyhan, chair of the organizing committee of NARC-2009 welcomed the attendees of W1008. This years meeting was the largest for W-1008, with over 50 participants. Chris Cramer, Committee Chair, opened the meeting with introductions and thanks to George Boyhan for organizing the meeting in conjunction with the National Allium Research Conference. Chris recognized Howard Schwartz for his leadership and taking the initiative to organize W1008. Participants were asked to update their NIMMS profiles to reflect the 3 objectives of the project plan. The committee also helps justify allocation of time and effort by experiment stations to onion research. Members were urged to invite colleagues to join the W1008 Committee, and to contact your AES Director regarding travel funds to W-1008 meetings. One of the benefits of this type of regional committee is that it raises the profile of onion thrips/IYSV problems to Congress and the USDA.

During the meeting, participants were able to give reports on their recent activities, including updates on the spread of IYSV, IPM programs for thrips and IYSV, and improvements in virus detection. Details are in the minutes.
Howard Schwartz briefly reviewed the Specialty Crops Research Initiative grant for 2009-2012, Ensuring US Onion Sustainability Breeding and Genomics to Control Thrips and IYSV. The director for this project is Mike Havey, USDA-ARS and University of Wisconsin with project co-PDs, Foo Cheung, J. Craig Venter Institute, Chris Cramer, New Mexico State University, Hanu Pappu, Washington State University and Howard Schwartz, Colorado State University. It consists of a multi-state approach with several extension, research and outreach projects, and collaboration with onion seed companies and growers.
Election of a new Secretary  Hanu Pappu, Washington, was unanimously elected. Christy Hoepting, New York, will assume duties of Vice-chair at the next meeting. Stuart Reitz succeeds Chris Cramer as Chair of the W1008 Committee.
Participants voted that the next W1008 meeting will be held in conjunction with the National Onion Association Annual meeting in San Antonio, Texas during the first week of December in 2009. The committee will work with NOA to combine the W-1008 meeting. Because of the large number of participants at this years meeting and the valuable exchange of information, it was decided to expand the next meeting to one full day.

The meeting was adjourned by Chris Cramer at 6:00 PM.

In addition, the proceedings of the 2008 National Allium Research Conference, including presentations on IYSV and onion thrips, are available at: http://www.caes.uga.edu/commodities/fruits/vidalia/NARC08/index.html.

Accomplishments

1. Screen onion germplasm for improved levels of tolerance to Iris yellow spot virus (IYSV) and thrips<br /> <br /> Colorado  Howard Schwartz, Colorado State University, Ft. Collins, CO - In Varietal trials. 40 entries were evaluated for thrips infestation and final IYSV incidence. Varieties with blue-green waxy leaves had more thrips than varieties with green leaves (glossy coating). OLYSOS5N5 and Colorado 6 had the lowest thrips throughout the season. White Wing, Arcero and Tequila tolerated a higher number of thrips. RedBull, Granero, Oro Blanco, Vaquero were most susceptible to thrips infestations. <br /> <br /> New Mexico  Chris Cramer, New Mexico State University, Las Cruces, NM - In February 2008, seed of 48 onion entries was sown in a field at the Leyendecker Plant Science Research Center in Las Cruces, NM. The entries consisted on short-, intermediate-, and long-day commercial cultivars and experimental breeding lines from the New Mexico State University breeding program. Seed was sown in two equally-spaced rows on the bed top. Plots were 0.6 m in width and 5.5 m in length. In the field, there were four blocks with each entry being represented with one plot per block. On the first and last bed of the study and at the front and back borders of the study, IYSV-infected bulbs were placed to ensure IYSV inoculum in the field. On each alternate bed, IYSV-susceptible breeding lines were sown in October, 2007 to act as disease spreader rows. The field was designed such that onion thrips would acquire IYSV from the infected bulbs, live on these bulbs until scape formation, then move to autumn-sown plants, and once these plants matured then move to the winter-sown test plants. At each move, thrips would transfer IYSV to those new plants. Onion plants were grown using standard cultural practices for growing onions in southern New Mexico except that chemical sprays were not applied for controlling onion thrips levels.<br /> <br /> Onion thrips levels were monitored throughout the growing season in the test plots and on the disease spreader rows. Samples were collected arbitrarily from IYSV-infected bulbs and plants that were being used in the spreader rows to confirm IYSV presence. Confirmation was done using ELISA and RT-PCR. <br /> <br /> On June 6, ten randomly-selected plants per plot were rated for IYSV symptom severity on a scale of 1 to 9 where 1 indicated no IYSV lesions and 9 indicated more than 50% of leaf tissue damaged due to coalescing IYSV lesions. These same ten plants were rated on a weekly basis for 7-8 weeks. In addition, ten additional randomly-selected plants per plot were rated for IYSV symptom severity using the scale mentioned above. Each week, a new set of ten randomly-selected plants was rated per plot. Rating continued for this method for 7-8 weeks also. For both rating methods, a mean IYSV symptom severity was calculated for each plot at each rating date. The two rating methods were compared to determine differences in symptom severity between them. On three different dates during the season, plant samples were collected from the same ten plants per plots that had been rated for IYSV symptom severity on a weekly basis. The plant samples were analyzed using ELISA to determine optical density values for each plant as a representation of IYSV titer. At the particular sampling and rating date, symptom rating and optical density value were analyzed to determine any correlation between these two factors on a per-plant, per plot, per entry, per year, and their interaction basis. With weekly severity ratings, the disease progression over time was calculated on a per-plant, per plot, and per entry basis. In addition, the change in optical density values over time was calculated on a per-plant, per plot, and per entry basis. The data collection for optical density values has not been completed for all samples so the data analysis has not been initiated. The data analysis for severity ratings has not been completed yet.<br /> <br /> New York  Brian Nault, Cornell University, Geneva, NY - There was a wide range in onion thrips damage among 46 onion cultivars screened for thrips resistance in upstate New York. On a scale of 1 to 9 (1= no damage and 9= heavy damage), the range in damage was 1.2 to 6.3. In general, varieties developed for growing in the western US were most resistant to onion thrips (e.g., OLS05N5, Colorado 6, T-433, NMSU 03-52-1, Delgado, Tioga, Peso, Cometa, Vaquero, Calibra and BGS-230).<br /> <br /> There also was a wide range in the percentage of IYSV infected plants among the onion cultivars screened for IYSV resistance. Some cultivars had over 75% infection, whereas others were below 25%. The most resistant varieties were Vaquero, 606-1, BGS-236, Bastille, Damascus OLS05N5 and SYN-G2.<br /> <br /> Cultivars that supported low populations of thrips, had less thrips damage and had low levels of IYSV infection included OLS05N5 and Vaquero.<br /> <br /> Oregon - Lynn Jensen, Clint Shock, Erik Feibert, and Monty Saunders, Oregon State University, Ontario, OR - Full season onion cultivars were evaluated for the severity of IYSV symptoms at two locations in the Treasure Valley area of eastern Oregon, with growing procedures relevant to commercial onion production. Ten cultivars were tested at a location with severe natural IYSV pressure and 46 cultivars were tested at a location of moderate pressure. Cultivars differed significantly in IYSV symptoms and many commercially relevant characteristics. Tissue samples were collected to relate variety IYSV symptoms with ELISA tests. <br /> <br /> 2. Study the biology and epidemiology of IYSV and thrips, and impacts of chemical, cultural and biological tactics that can reduce their impacts upon onions.<br /> <br /> Colorado  Howard Schwartz, Colorado State University, Ft. Collins, CO - In a spatial and temporal distribution of thrips and IYSV study, areas that had higher thrips also tended to have higher IYSV. IYSV is present in all production areas of Colorado. The effect of thrips and IYSV on yield was inconsistent. Relationships between thrips, IYSV and edaphic properties appear to be weak. A poster on this study was presented at the NARC (see presentations at national meetings: Schwartz et al. #17).<br /> <br /> Results from Actigard trials were summarized. In general, Actigard applied pre-bulb can reduce the incidence of IYSV. In a commercial field with moderate pressure, IYSV was reduced 4 to 17%, and jumbo yield was increased 11 to 54% by most of the Actigard treatments. <br /> <br /> The role of onion transplants in the movement of thrips and IYSV was studied. Thrips were recovered in 56 to 100% the sources examined from Arizona (Phoenix), Texas (southern) and California (Sacramento Valley). Incidence of IYSV in these transplants varied from 0 to 56% (up to 5% of plants within a source). Transplants could serve as potential source of thrips and IYSV. Volunteer onions continue to test positive for IYSV from 2004 to 2008 and may serve as a green bridge for IYSV between seasons.<br /> <br /> Studies on the localization of IYSV in onion were conducted. Results showed a great degree of variability for the presence of IYSV in different parts (leaf, neck, bulb, basal plate, and root) showing uneven distribution of the virus within the infected plant. <br /> <br /> Bulb-borne infection of IYSV: Bulbs were collected from field-grown, symptomatic plants (19-24 weeks) after bolting. All the foliage was removed, and bulbs were planted in a greenhouse. The resulting plants were positive for IYSV. This suggests possible IYSV transmission through bulb. Discussion followed on how to ensure that the harvested bulbs were completely free of viruliferous thrips before they were planted in the greenhouse. <br /> <br /> Studies to identify weed hosts continued in 2008. Several weeds were found positive for IYSV using ELISA and RT-PCR. Weeds found to be positive for IYSV were used as source plants for onion thrips for acquisition. These thrips were able to transmit IYSV to onion. Studies to test if thrips could transmit IYSV from infected onion to weeds are in progress. <br /> <br /> Idaho  Krishna Mohan, Ram Sampangi, Mike thornton, University of Idaho, Parma, ID - Several weeds growing in and around onion fields in the Treasure Valley were sampled and tested for IYSV. Many of them were positive by ELISA but could not be verified by RT PCR. Hanu Pappu, Washington State University is working to resolve the discrepancies between ELISA and RT PCR results for IYSV. These discrepencies have occurred in numerous weed surveys. Ram will repeat ELISA testing using kits from different commercial sources to determine if there is a difference in the results of testing weeds. <br /> <br /> Seasonal dynamics of thrips populations were studied in onion fields in the Treasure Valley. A poster was presented at the NARC (see presentations at national meetings #16). <br /> <br /> Insecticidal treatments including fipronil and Cruiser were evaluated for thrips control and their effect on final IYSV incidence in the Treasure Valley growing region. Carbamate insecticides like Carzol and Lannate were evaluated for potential plant health benefits on onion. It appeared that carbamate insecticides had no effect on plant health. This project was presented at the NARC (see presentations at national meetings #24) <br /> <br /> New York  Brian Nault, Cornell University, Geneva, NY - Volunteer onion plants growing in onion fields and cull piles, as well as selected weed species are sources of IYSV in NY. These sources are known hosts for both IYSV and onion thrips. Among these sources, weeds may contribute the most to annual spread of this disease because their densities far outnumber densities of volunteer onions in the onion-cropping system. However, more research is needed to examine this hypothesis. Monitoring temporal and spatial relationships between IYSV, weed hosts, onion thrips and the onion crop is critical to identify which onion fields are at highest risk for IYSV and to be able to target IYSV management strategies accordingly.<br /> <br /> Onion plants imported from AZ for transplanting in NY tested negative for IYSV, and therefore transplants are not likely a source in NY. Imported bulbs discarded into cull piles during repackaging could be a source, but may not be a major one. We learned this summer that many imported bulbs do not sprout even when provided conditions to do so; perhaps these bulbs were treated with a sprout inhibitor prior to harvest. If imported bulbs never produce foliage to support another generation of thrips, IYSV cannot be transferred from those bulbs to nearby onion fields. Additionally, cull piles are small, geographically isolated areas and many are located great distances from onion fields. <br /> <br /> Early in the season (through June), onion thrips densities in transplanted onion fields were significantly higher than densities in direct-seeded onion fields.<br /> <br /> We were able to detect IYSV much earlier in 2008, and more of the fields in 2008 had higher IYSV prevalence levels prior to harvest compared with 2007. When direct-seeded fields had higher levels of IYSV than their transplanted counterparts, the difference was much greater than when transplanted fields had higher levels of IYSV than their direct-seeded counterparts. This suggests that, contrary to what we original hypothesized, the direct-seeded fields may be more at risk to IYSV than transplanted fields even though transplanted fields had significantly higher populations of thrips early in the season.<br /> <br /> In general, direct-seeded fields are harvested later than transplanted fields. This could affect IYSV levels by allowing the virus more time to spread within the field, and by concentrating infected thrips migrating out of harvested fields into the remaining fields that were still standing. In fact, our results suggest that later season adult thrips behavior may be more important in the epidemiology of IYSV in New York onions than early season thrips populations. <br /> <br /> Insecticides that provided the best protection against onion thrips included Radiant SC, Movento 240 SC and Carzol SP. Section 18s for Movento and Carzol for thrips control in onion have been submitted to New York State DEC and EPA for the 2009 season.<br /> <br /> Several insecticide application sequence approaches were evaluated and the best approaches were those that included two consecutive applications of the products mentioned above. However, more research is needed to identify the best sequence of these products during the season.<br /> <br /> Timing insecticide sprays for thrips control using action thresholds reduced the number of applications relative to a calendar-based spray program. Yet, the efficacy of the product had a dramatic impact on the number of applications made (i.e., most effective products were sprayed fewer times relative to less effective products).<br /> <br /> Brian Nault submitted a package to the New York State Department of Environmental Conservation that led to a Specific Emergency Exemption (FIFRA Section 18) for the use of formetanate hydocloride (Carzol SP) on onion for onion thrips control. The Crisis Exemption request was granted by NYSDEC from May- September 2008.<br /> <br /> Brian Nault wrote a letter of support that led to the New York Department of Environmental Conservation granting a FIFRA Section 24(c), Special Local Needs Label, for the use of Radiant SC on onion for onion thrips control in New York. (Valid through 12/31/2008).<br /> <br /> Utah  Dan Drost, Utah State University - A statewide IYSV survey was conducted where fields were scouted every 2-3 weeks and samples collected. Symptomless plants tested positive for IYSV via ELISA tests in July, but symptoms did not show up until August. <br /> <br /> A weed survey was conducted in collaboration with Hanu Pappu, Washington State University. Two new weed species were identified as hosts of IYSV including a type of salt bush, Atraplex, and a Foxtail, which is the first detection of IYSV in a grass species. This stresses the importance of keeping voucher specimens of weed hosts. A major effort is underway to investigate reduced nitrogen applications in combination with crop rotations and use of composts and other additives that increase the biological activity of the soil to reduce onion thrips and IYSV. <br /> <br /> In Utah, some growers have adopted a rotation which includes 5 years of alfalfa, 1 year of field corn and 1 year of wheat before planting onions. Ninety units of nitrogen are used per year. In this system, the grower went from using 10 insecticide sprays per season to 1 in 5 years to control thrips. Onions look paler green and yield about 10% less, but the savings in fertility and insecticide inputs more than make up for the lower yield, economically. In another project, trap crops including buck wheat and carrots are being investigated to reduce onion thrips populations.<br /> <br /> Washington  Lindsay du Toit, Tim Waters and Hanu Pappu Washington State University - A sentinel plot of five onion cultivars that were each treated or not treated with insecticides was monitored in 2008. Thrips counts and yield were assessed, but iris yellow spot did not develop in that trial. These sentinel plots were isolated from any onion seed crops, and in one of the few sections of the Columbia Basin (central Basin) in which IYS has not become a problem for onion production (one of the few sections in which seed crops aren't grown). Interesting preliminary data suggest that certain foliar insecticide treatments may exacerbate powdery mildew on onion plants. <br /> <br /> Severe iris yellow spot was found in at least 3 onion seed crops in the northern Columbia Basin in 2008. One field had >90% lodging 3 weeks prior to harvest. IYSV is definitely still causing significant problems in onion seed production in the northern Columbia Basin of Washington. <br /> <br /> New records of IYSV confirmed by Hanu Pappu include Mason Valley in Nevada, and new regions in Northern California. New hosts include garlic, spiny sowthistle and foxtail. <br /> <br /> Work to develop a procedure for mechanical transmission of IYSV into onion is underway, which would be useful for screening for resistance. Some progress has been made, but high efficiency is lacking. The NSs antibody is useful in quickly identifying IYSV transmitters among thrips, as not all thrips carrying the virus can transmit it. Then, it can be determined when most of the viriliferous thrips are entering or present in the field. <br /> <br /> Western blots are being investigated for improved accuracy of identifying IYSV in weeds, as there continues to be discrepancy between ELISA strongly testing positive and PCR testing negative in weeds.<br /> <br /> 3. Transfer information on progress dealing with IYSV and thrips biology and IPM strategies to the onion industry and other interested parties<br /> <br /> New York  Brian Nault, Cornell University, Geneva, NY - Several meetings were held in 2008 to inform NYs onion industry about results from this project: the Annual Winter New York Onion Industry Council Meeting in Ithaca in January, the Empire State Fruit and Vegetable EXPO in Syracuse in February, the Annual Summer New York Onion Industry Council Meeting in Elba in July and the Elba Muck Onion Meeting in Elba in August. Additionally, an annual workshop was held in Ithaca that included a session to update Cornell Cooperative Extension Educators about results from this project. Please see the list of presentations to grower groups for additional information.<br /> <br /> Oregon/Idaho - Lynn Jensen, Clint Shock, Erik Feibert, and Monty Saunders, Oregon State University, Ontario, OR - Information pertinent to IYSV and thrips biology was transferred to growers, other onion industry parties, and the public through numerous meetings, field days, publications, and the internet.<br />

Publications

Publications<br /> <br /> Gent, D. H., and Schwartz, H. F. 2008. Iris yellow spot. pp. 80-83. In, Compendium of Onion and Garlic Diseases, 2nd Ed. APS Press, St. Paul, MN.<br /> <br /> Hoepting, C.A., J. Allen, K. Vanderkooi, M. Hovius, H.R. Pappu, and M.R. McDonald. 2008. First Report of Iris yellow spot virus on Onion in Canada. Plant Disease 92:318.<br /> <br /> Hsu, C., C. Hoepting, A. Shelton and B. Nault. 2008. Seasonal prevalence of Iris yellow spot virus in transplanted and direct-seeded onion fields, pp. 60-66. In Program and Proceedings of the 2008 National Allium Research Conference, Savannah, GA.<br /> <br /> Huchette, O., C. Bellamy, R. Filomenko, B. Pouleau, S. Seddas, and H.R. Pappu, 2008. Iris yellow spot virus in Shallot and Onion in France. Plant Health Progress. doi:10.1094/PHP-2008-0610-01-BR. <br /> <br /> Larentzaki, E., J. Plate, B. A. Nault and A. M. Shelton. 2008. Impact of straw mulch on populations of onion thrips (Thysanoptera: Thripidae) in onion. J. Econ. Entomol. 101(4): 1317-1324.<br /> <br /> Larentzaki, E., A. M. Shelton, and J. Plate. 2008. Effect of kaolin particle film on Thrips tabaci (Thysanoptera: Thripidae), oviposition, feeding and development on onions: A lab and field case study. Crop Protection 27: 727-734.<br /> <br /> Nault, B. A., M. Fuchs, C. Hsu, E. Smith and A. Shelton. 2008. Potential sources of IYSV, relationship between IYSV and onion thrips, and thrips control in New York, 9-12. In: Proceedings of the 2008 Wisconsin Muck Crops Research Update. March 4, 2008. Portage, WI. University of Wisconsin Extension and Wisconsin Muck Growers Association.<br /> <br /> Nault, B. A., and M. L. Hessney. 2008. Onion thrips control in onion, 2007. Arthropod Management Tests. 33: E20.<br /> <br /> Nault, B., A., C. Hsu, E. Smith, A. Shelton, M. Fuchs, C. Hoepting and A. DiTommaso. 2008. Identifying sources of IYSV in New Yorks cropping system, pp. 67-72. In Program and Proceedings of the 2008 National Allium Research Conference, Savannah, GA. <br /> <br /> Nault, B. A. and A. M. Shelton. 2008. Insecticide efficacy and timing of sprays for onion thrips control, pp. 52-56. In: Proceedings of the 2008 Empire State Fruit and Vegetable Expo. February 12-14, 2008. Syracuse, NY. Cornell Cooperative Extension and New York State Vegetable Growers Association.<br /> <br /> Nault, B. A. and A. M. Shelton. 2008. Update: Insecticides and sequences of applications for onion thrips control. Cornell University Cooperative Extension Vegetable Program. Veg Edge 4(7): 6-9.<br /> <br /> Nault, B. A. and A. M. Shelton. 2008. Insecticides and sequences of applications for onion thrips control in onion fields. Cornell University Cooperative Extension of Orange County. Muck and Mineral. June 2008. pp. 1-3. <br /> <br /> Nault, B. A. and A. M. Shelton. 2008. Insecticides and timing for onion thrips control. Cornell University Cooperative Extension Vegetable Program. Veg Edge 4(6): 12-14.<br /> <br /> Pappu, H.R., and M.E. Matheron. 2008. Characterization of Iris yellow spot virus from onion in Arizona. Plant Health Progress. doi:10.1094/PHP-2008-0711-01-BR.<br /> <br /> Pappu, H.R., I.M. Rosales, and K.L. Druffel. 2008. Serological and molecular assays for rapid and sensitive detection of Iris yellow spot virus (Genus Tospovirus, Family Bunyaviridae) infection of bulb and seed onion crops. Plant Disease 92:588-594. (cover page of the issue).<br /> <br /> Shock, C.C., E.B.G. Feibert, L.B. Jensen, S.K. Mohan, and L.D. Saunders. 2008. Onion variety response to iris yellow spot virus. HortTechnology. 18:539-544.<br /> <br /> Ward, L.I., Z. Perez-Egusquiza, J.D. Fletcher, F.M. Ochoa Corona, J.Z. Tang, L.W.Liefting, E.J. Martin, B.D. Quinn, H.R. Pappu and G.R.G. Clover. 2008. First Report of Iris yellow spot virus on Allium cepa in New Zealand. New Disease Reports http://www.bspp.org.uk/ndr/july2008/2008-43.asp British Society for Plant Pathology.<br /> <br /> Waters, T. D., and D. B. Walsh. Thrips control on dry bulb onions in Washington State, 2007. Arthropod Management Tests. 33: E3<br /> <br /> Research Reports: Abstracts and Papers at International Professional Meetings <br /> <br /> Pappu, H.R. and C.C. Shock, 2008. Progress toward understanding and managing Iris yellow spot tospovirus epidemics in onion bulb and seed crops. The 3rd Conference of the International Working Group on Legume and Vegetable Viruses (IWGLVV), 20-23 August 2008, Ljubljana, Slovenia.<br /> <br /> <br /> Research Reports: Abstracts and Papers at National Professional Meetings <br /> <br /> Bag, S., K.L. Druffel, and H.R. Pappu. 2008. Genome Characterization and genetic Diversity of Iris yellow spot virus. National Allium Research Conference, Savannah, GA. December 11-13, 2008.<br /> <br /> Buhrig, W. and M. Thornton. Strategies to Improve Early Season Thrips Control and Suppress Iris Yellow Spot Virus in Onions. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia. <br /> <br /> Diaz-Montano, J., A. M. Shelton, B. A. Nault and M. Fuchs. 2008. Screening for resistance and impact onion thrips (Thrips tabaci Lindeman) and Iris yellow spot virus on onion growth. Eastern Branch - Entomological Society of America Annual Meeting, Syracuse, NY. <br /> <br /> Diaz-Montano, J., A. M. Shelton, B. A. Nault and M. Fuchs. 2008. Screening for resistance and yield losses caused by onion thrips (Thrips tabaci Lindeman) and Iris yellow spot virus on onions. Entomological Society of America Annual Meeting, Reno, NV.<br /> <br /> Drost, D., J. Reeve, K. Evans, L. Andreasen, and D. Alston. Cultural Management of Onion Thrips And Iris Yellow Spot Virus. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia.<br /> <br /> Feibert, E.B.G.,C.C. Shock, and L.D. Saunders. 2008. Irrigation intensity, irrigation frequency, and emitter flow rate for drip-irrigated onion. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia.<br /> <br /> Gitaitis, R. Detection and Distribution of Iris Yellow Spot Virus in Spiny Sowthistle in Georgia. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia.<br /> <br /> Hsu, C. L., C. Hoepting, A. M. Shelton and B. A. Nault. 2008. Tracking the spread of Iris yellow spot virus (IYSV) in onion fields. Entomological Society of America Annual Meeting, Reno, NV.<br /> <br /> Hsu, C., C. Hoepting, A. Shelton and B. Nault. 2008. Seasonal prevalence of Iris yellow spot virus in transplanted and direct-seeded onion fields. 2008 National Allium Research Conference, Savannah, GA.<br /> <br /> Hsu, C., D. Shah, M. Fuchs, A. Shelton and B. Nault. 2008. Differences in thrips pressure and prevalence of Iris yellow spot virus (Tospovirus) in transplant and direct-seeded onions. Eastern Branch - Entomological Society of America Annual Meeting, Syracuse, NY.<br /> <br /> Jensen, L.B., and C.C. Shock. Oregon progress on the biology and management of Iris yellow spot virus (IYSV) and thrips in onions. Annual meeting of the W1008 working group. December 10, Savannah, Georgia.<br /> <br /> Jensen, L.B., C.C. Shock, and L.D. Saunders. 2008. Managing insecticides for maximum efficacy against thrips in dry bulb onion in the Oregon / Idaho production region. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia<br /> <br /> Nault, B., A., C. Hsu, E. Smith, A. Shelton, M. Fuchs, C. Hoepting and A. DiTommaso. 2008. Identifying sources of IYSV in New Yorks cropping system. 2008 National Allium Research Conference, Savannah, GA.<br /> <br /> Nault, B., A. Shelton, M. Fuchs, C. Hsu, E. Smith, and M. Hessney. IYSV epidemiology, thrips ecology and management in New York. W-1008 Onion IYSV and Thrips Annual Meeting. Denver, CO.<br /> <br /> Nault, B. A., A. Shelton, M. Fuchs, A. Taylor, C. Hsu, E. Smith, P. Jentsch, M. Hessney and H. Grimsland. 2008. Summary of research on onion maggot, onion thrips and Iris yellow spot virus in New York. New York Onion Industry Council Winter Meeting, Ithaca, NY. January 22, 2008. Speaker, 15 minutes. Attendees: 30. Onion growers, CCE educators and Cornell faculty.<br /> <br /> Sampangi, R.K., S.K. Mohan, C.C. Shock,and E.B.G. Feibert. 2008. Abundance and population dynamics of onion thrips and incidence of iris yellow spot virus in Treasure Valley region of Idaho and Oregon. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia<br /> <br /> Schwartz, H., S. Fichtner, D. Gent, R. Khosla, D. Inman, W. Cranshaw, M. Camper, and L. Mahaffey. P-14 Spatial and Temporal Distribution of Thrips and IYSV of Onion in Colorado. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia.<br /> <br /> Schwartz, H., D. Gent, S. Fichtner, W. Cranshaw, L. Mahaffey, M. Camper, K. Otto, and M. McMillan. Management of Onion Thrips and IYSV with Straw Mulch and Biopesticides. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia.<br /> <br /> Schwartz, H. F., K. Otto, S. Szostek, C. Boateng, W. S. Cranshaw, M. A. Camper, and L. Mahaffey. Thrips And IYSV Sources in Colorado Onion Production Systems. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia.<br /> <br /> Shock, C.C. 2008, E.B.G Feibert, L.B. Jensen, S.K. Mohan, R.K. Sampangi, H. Pappu, and L.D. Saunders. 2008. Onion variety response to iris yellow spot virus. 2008. National Allium Research Conference, December 10-13, Savannah, Georgia.<br /> <br /> Shock, C.C.,E.B.G. Feibert, and L.D. Saunders. 2008. Irrigation scheduling for drip-irrigated onion. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia.<br /> <br /> Smith, E., A. DiTommaso, M. Fuchs, A. M. Shelton and B. A. Nault. 2008. Identifying weed hosts for onion thrips (Thrips tabaci) and implications for Iris yellow spot virus management in onion. Entomological Society of America Annual Meeting, Reno, NV. (Note: Awarded second place in Student Competition for the Presidents Prize in the Section Plant-Insect Ecosystems: Tri-trophic Interactions).<br /> <br /> Smith, E., C. Hsu, M. Fuchs, A. Shelton, C. Hoepting and B. Nault. 2008. Assessing possible sources of onion-thrips transmitted Iris yellow spot virus in New York onion fields. Eastern Branch - Entomological Society of America Annual Meeting, Syracuse, NY.<br /> <br /> Thornton, M. and W. Buhrig. Impact of Carbamate Insecticides on Thrips Populations and Iris Yellow Spot Virus Incidence in Onions. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia.<br /> <br /> Volker, K. Impact of Surround Wp Crop Protectant for Management of Thrips Infestation and Overall Plant Health. 2008 National Allium Research Conference, December 10-13, Savannah, Georgia.<br /> <br /> Reports at Grower meetings and field days:<br /> <br /> Diaz, John M., A. Shelton and B. Nault. 2008. Onion resistance to onion thrips and IYSV. Empire State Fruit and Vegetable Expo, Syracuse, NY. February 13, 2008. Cornell Cooperative Extension and New York State Vegetable Growers Association. Co-author, 10 minutes. Attendees: 80. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Feibert, E.B.G., and C.C. Shock. 2008. Cultural practice options to reduce IYSV risks. OSU Malheur Experiment Station Onion Variety Day, Ontario, OR, August 26, 2008. <br /> <br /> Fuchs, M., C. Hsu, A. Shelton and B. Nault. 2008. Regional survey results and field incidence of IYSV. Empire State Fruit and Vegetable Expo, Syracuse, NY. February 13, 2008. Cornell Cooperative Extension and New York State Vegetable Growers Association. Co-author, 20 minutes. Attendees: 80. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Hoepting, C.A. 2008. Iris yellow spot virus on onions in New York State. 57th Annual Muck Vegetable Growers Conference, Bradford, Ontario, Canada, March 26-27, 2008. 70 attendees.<br /> <br /> Hoepting, C.A. 2008. Onion thrips management strategies. Fall Vegetable Workshop, Granby, NY, November 19, 2008. 15 attendees. <br /> <br /> Hoepting, C.A. and B.A. Nault. 2008. Advances in the control of onion thrips  a report from New York. 57th Annual Muck Vegetable Growers Conference, Bradford, Ontario, Canada, March 26-27, 2008. 70 attendees.<br /> <br /> Jensen, L. 2008. Onion ag issues. Treasure Valley Ag Show, Ontario, OR, January 19.<br /> <br /> Jensen, L. 2008. Thrips control in onions. Idaho/Malheur County Onion Growers Annual Meeting, Ontario, OR, February 5.<br /> <br /> Jensen, L. 2008. Thrips identification and control. Fertilizer Field Representative Workshop. Oregon State University, Ontario, OR, May 22, 2008.<br /> <br /> Jensen, L. 2008. Insecticides for thrips control in onions. OSU Malheur Experiment Station Field Day, Ontario, OR, July 9, 2008.<br /> <br /> Jensen, L. 2008. Movento for thrips control in onions. Bayer Tour. Ontario, OR, August 11, 2008.<br /> <br /> Jensen, L. 2008. Controlling onion thrips. Treasure Valley Field Tour. Ontario, OR, August 15, 2008.<br /> <br /> Jensen, L. 2008. Strategies for thrips control in onions. Pacific Northwest Vegetable Association Annual Meeting. Kennewick, WA, November 19, 2008.<br /> <br /> Nault, B. 2008. Onion insect management. Elba Muck Onion Twilight Meeting, Elba, NY. August 5, 2008. Cornell Cooperative Extension Vegetable Program. Speaker, 15 minutes. Attendees: 40. Onion growers, vegetable industry representatives and crop consultants.<br /> <br /> Nault, B. A. 2008. Getting the upper hand on onion thrips and IYSV. Wisconsin Muck Farmers Association Annual Meeting. Portage, WI. March 4, 2008. Speaker, 45 min. presentation.<br /> <br /> Nault, B., C. Hsu, E. Smith and J. Diaz-Montano. 2008. Onion thrips and IYSV research update and demonstration. New York State Onion Industry Council Summer Tour and Meeting, Elba, NY. Cornell Cooperative Extension. Co-speaker, 20 minutes. Attendees: 60. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Nault, B., and A. Shelton. 2008. Thrips control using insecticides: What and when to apply? Empire State Fruit and Vegetable Expo, Syracuse, NY. February 13, 2008. Cornell Cooperative Extension and New York State Vegetable Growers Association. Speaker, 20 minutes. Attendees: 80. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Shock, C.C. 2008. Perspectives on onion irrigation scheduling and drip irrigation. Stress on onion and its impact on ISYV development. 48th annual meeting of the Malheur County and Eastern Idaho Onion Growers Annual Meeting, Four Rivers Cultural Center, Ontario, February 5, 2008.<br /> <br /> Shock, C.C. 2008. Onion variety performance. 48th annual meeting of the Malheur County and Eastern Idaho Onion Growers Annual Meeting, Four Rivers Cultural Center, Ontario, February 5, 2008.<br /> <br /> Shock, C.C. 2008. Perspectives on onion irrigation scheduling and drip irrigation. Drip Irrigation Conference, Clearwater Supply. February 6, 2008.<br /> <br /> Shock, C.C. 2008. Soil moisture requirements for onions. Pacific Northwest Vegetable Association Annual Conference and Trade Show, Three Rivers Convention Center, Kennewick, WA, November 19-20.<br /> <br /> Shock, C.C. and E.B.G. Feibert. 2008. Irrigation, fertilization, and cultivar to manage IYSV. OSU Malheur Experiment Station Field Day, Ontario, OR, July 9, 2008.<br /> <br /> Waters, T.D. and du Toit, L. WSU Onion Field Day, Othello, WA, August 28, 2008. <br /> Waters. T.D. 2009 Annual Conference and Trade Show of the Pacific Northwest Vegetable Association, Kennewick, WA, November, 19 2008.<br /> <br /> Internet Resources<br /> <br /> Jensen, L.B. 2008. Insecticide efficacy trial for thrips control in dry bulb onions  2007. Oregon State University Agricultural Experiment Station, Special Report 1087:52-56. http://www.cropinfo.net/AnnualReports/2007/InsecticideEfficacyTrialThripsBulbOnions2007.html<br /> <br /> Jensen, L.B., C.C. Shock, and L.D. Saunders. 2008. Managing Carzol® for Maximum Efficacy Against Thrips  2007. Oregon State University Agricultural Experiment Station, Special Report 1087:57-73. http://www.cropinfo.net/AnnualReports/2007/ManagingCarzol2007.html.<br /> <br /> Schwartz, H. F. 2008. Web site dedicated to information and resources on thrips and IYSV. http://www.alliumnet.com/index.htm<br /> <br /> Shock, C.C., E.B.G. Feibert, L.D. Saunders, L. Jensen, K. Mohan, and H. Pappu. 2008. 2007 Onion variety trials. Oregon State University Agricultural Experiment Station, Special Report 1087:17-25. http://www.cropinfo.net/AnnualReports/2007/OnionVarietyTrials2007.html<br /> <br /> Shock, C.C., E.B.G. Feibert, L.D. Saunders, L.B. Jensen, and K. Mohan. 2008. Management of onion cultural practices as a means to control the expression of iris yellow spot virus. Oregon State University Agricultural Experiment Station, Special Report 1087:34-51. http://www.cropinfo.net/AnnualReports/2007/IrisYellowSpotVirusOnion2007.html.<br />

Impact Statements

1. " Due to better knowledge of the transmission of IYSV, growers are practicing more vigilance in destroying onion culls. Since many growers are planting over-wintering fields further from summer production fields and destroying more culls, these actions help break the natural green bridge keeping IYSV pressure high from one production year to the next. Overall, there has been less IYSV expression in the Treasure Valley of Idaho-Oregon in 2007 and 2008 than in 2005 and 2006.

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Report Information

Participants

Howard Schwartz, Colorado State University, Ft. Collins, CO, howard.schwartz@colostate.edu;Christy Hoepting, Cornell University, Albion, NY, cah59@cornell.edu;Chris Cramer, New Mexico State University, Las Cruces, NM , cscramer@nmsu.edu ;Stuart Reitz, USDA-ARS, Tallahassee, FL, stuart.reitz@ars.usda.gov;Krishna S. Mohan, University of Idaho, Parma, ID, kmohan@uidaho.edu;Kristie Buckland, Utah State University, Logan, UT, Kristie.buckland@usu.edu ;Lynn Jensen, Oregon State University, Ontario, OR, lynn.jensen@oregonstate.edu;Clint Shock, Oregon State, Ontario, OR , Clinton.shock@oregonstate.edu;Steve Beer, Cornell University, Ithaca, NY, svb1@cornell.edu;Cynthia Hsu, Cornell University NYSAES, Geneva, NY , clh33@cornell.edu;Robert T. Sakata, Sakata Farms, Brighton, CO , RTSakata@aol.com;Mary Ruth McDonald, University of Guelph, Guelph, ON, mrmcdona@uoguelph.ca;Charles Boateng, Colorado State University, Charles.boateng@colostate.edu;David Burrell, National Onion Labs, info@onionlabs.com;Juan Anciso, Texas A & M, j-anciso@tamu.edu;Mario Perches, DP Seeds, mperches@dpseeds.com;Shannon Pike, Enxa USA, Shannon.pike@enzausa.com;Bruce Scheur, Michigan grower, mrcelery@iserv.net;Fern Larose, University of Guelph;Ralph Harris, Decade Products, harrisr@decadeproducts.com;Arlin Plender, Decade Products, plendra@decadeproducts.com;Brent Hines, Colorado Grower, brent@kaycee.net;Jason Verkaik, Carron Farms, Bradford, Ontario, Canada, jrverkaik@hotmail.com;Tom Gordan, American Takii, tgordan@takki.com;Lee Sommers, Colorado State University, Lee.Sommers@colostate.edu;Brent Clements, Onion World, dbrent@columbiapublications.com;;

Brief Summary of Minutes

See attached file.

Accomplishments

Objective 1. Screen onion germplasm for improved levels of tolerance to Iris yellow spot virus (IYSV) and thrips<br /> <br /> Colorado  Howard Schwartz, Colorado State University, Ft. Collins, CO - During 2009, the Colorado team identified the following cultivars and breeding lines with significantly greater plant vigor after season-long exposure to thrips and the virus: NUN7606ON, Mesquite, OLYS03-207, OLYS05N5, OLYS03-209, and OLYX06-25. Field losses from thrips pressure averaged 15 to 35 percent for cultivars such as Cometa, Gunnison, Arcero, and Red Bull, while other cultivars such as Colorado 6, Granero and Mesquite had less than 5 percent reduction in yield when not protected by multiple sprays of insecticides. The evaluation design verified that screening nurseries planted in fields with a history of problems from onion thrips and IYSV could provide moderate to severe pest and disease pressure to enable the identification of less susceptible onion entries (varieties or germplasm). <br /> <br /> New Mexico  Chris Cramer, New Mexico State University, Las Cruces, NM - Seventy-five onion plant introduction (PI) accessions from the U.S. germplasm collection and 31 intermediate- and long-day commercial cultivars and experimental breeding lines from the New Mexico State University breeding program were evaluated for the number of thrips per plant, leaf color, leaf waxiness, leaf axil pattern, Iris yellow spot (IYS) disease symptoms, and bulb yield. In general, thrips number per plant increased from 12 to 14 weeks post transplanting while the number decreased afterwards up to 20 weeks. At this time, there were fewer thrips per plant than at 12 weeks. At 14 weeks, PI 248753, PI 248754, PI 274780, and PI 288272 averaged less than three thrips per plant that was less than most entries tested and less than the average number of thrips per plant for all entries, 21. These accessions produced dark green leaves that had a moderate amount of waxy coating. At this time, there were very few differences in thrips number per plant among the commercial cultivars and experimental breeding lines tested. OLYS 05N5 exhibited fewer thrips per plant than several entries. By 16 weeks, there were no differences among entries for thrips number per plant. <br /> <br /> Seventeen accessions were rated as having light to dark green leaf color, three were rated as having semi-glossy to glossy leaves, and one possessed an open leaf axil pattern. PI 239633 and PI 289689 possessed glossy foliage that was dark green in color. PI 258956, PI 546188, and PI 546192 possessed semi-glossy foliage that was dark green in color. Most of the commercial cultivars and experimental breeding lines tested were rated as having leaves that were light to dark green in color. Only two entries, NMSU 07-30-2 and 07-54-1, were rated as having semi-glossy to glossy leaves. There were very few differences in leaf axil pattern among the entries tested in this group. At 20 weeks, PI 239633, PI 264320, PI 321385, PI 546100, PI 546115, PI 546188, and PI 546192 exhibited less severe IYS symptoms than other accessions. Four weeks later, IYS symptoms became more severe on plants of these accessions, however; plants of PI 546115 and PI 546192 exhibited less severe symptoms than most other accessions that had not matured by this time. At each rating time, there were no differences in IYS disease severity and incidence among the commercial cultivars and experimental breeding lines tested. PI 239633, PI 258956, PI 264320, PI 321385, and PI 546100 exhibited a jumbo market class yield that was greater than the yield of other entries. Individual plants, that exhibited few IYS disease symptoms, were selected at bulb maturity from 14 different accessions and 12 different commercial cultivars and experimental breeding lines for a total of 265 bulbs. These bulbs are being self-pollinated and test-crossed to male-sterile lines in the hopes of finding individual progeny that possess a higher level of IYS tolerance.<br /> <br /> New York  Brian Nault, Anthony Shelton and John Diaz-Montano, Cornell University, Geneva, NY - Fifteen onion cultivars suspected to be resistant to onion thrips were examined in the field for potential resistance to IYSV. There were significantly fewer onion thrips larvae on these resistant varieties (e.g., NMSU 03-52-1, Peso, Medeo, Cometa, Granero, White Wing, Calibra, Colorado 6, Mesquite, Arcero, OLYS05N5, Vaquero, Delgado and T-433) compared with the susceptible cultivar Nebula. However, there were no significant differences in the percentages of plants infected with IYSV among any of the cultivars, including Nebula, as determined by DAS-ELISA. The mean percentages of cultivars infected with IYSV varied from 37 to 70%. These results suggest that there is no resistance to IYSV among these thrips-resistant cultivars.<br /> <br /> A no-choice laboratory experiment was conducted to determine if the thrips resistance in the thrips-resistant cultivars was mediated in part by antibiosis. Plants representing each cultivar were individually caged and then infested with the same number of onion thrips adults and then the number of larvae was recorded 2 wks later. The thrips-resistant cultivars (e.g., Cometa, Colorado 6, Vaquero, White Wing, Delgado, Granero, OLYS05N5, NMSU 03-52-1 and several others) had significantly fewer larvae than susceptible cultivars. Therefore, these results suggest that antibiosis is responsible in part for the resistance against onion thrips. <br /> <br /> A choice-experiment also was conducted to determine if thrips resistance is also partially mediated by antixenosis. Plants representing each of the cultivars mentioned above were grouped into a cage and onion thrips adults were released into the cage. A couple of days later, the number of adults on each plant was recorded. Significantly more adults were found on the susceptible cultivar compared with all of the resistant ones. These results suggest that antixenosis is in part responsible for the resistance. These findings were consistent with previous research in which thrips-resistant cultivars with low numbers of thrips and low levels of thrips feeding damage had yellow-green leaf color, while susceptible cultivars had blue-green leaf color. <br /> <br /> Oregon - Lynn Jensen, Clint Shock, Erik Feibert, and Monty Saunders, Oregon State University, Ontario, OR - Based on on farm and on station trials, onion varieties have been tentatively identified that are more and less tolerant to IYSV. Some of the apparently tolerant lines were not seriously considered by growers two years ago. As of last year, tissue samples were collected to relate variety IYSV symptoms with ELISA tests. <br /> <br /> Objective 2. Study the biology and epidemiology of IYSV and thrips, and impacts of chemical, cultural and biological tactics that can reduce their impacts upon onions.<br /> <br /> Colorado  Howard Schwartz, Colorado State University, Ft. Collins, CO - The Colorado program compared methods to detect IYSV infection in onion tissue, and all methods were effective: ELISA, RT-PCR, TBIA (Tissue Blot Immuno Assay), and NA-hyb (Nucleic Acid Hybridization). Additional work is warranted to identify an efficient, effective and economical method to test onion and other materials for IYSV. <br /> <br /> Yield loss quantification was conducted in a preliminary Colorado greenhouse study to document the need for funding research on thrips and IYSV, and finding control options. Colorado 6 yield was reduced 15 percent by IYSV, 50 percent by thrips and 60 percent by IYSV and thrips; compared to the yield of Talon which was reduced 60 percent by IYSV, thrips, or IYSV and thrips. Other greenhouse studies determined that 5 viruliferous thrips infected plants within 2 days of feeding (preliminary results). <br /> <br /> Idaho  Krishna Mohan and R.K. Sampangi, University of Idaho, Pharma, ID - Overwintering locations and emergence of thrips from soil: Soils were sampled using soil augers at different locations in and around onion fields with disease [inside the field, outside the field on margins and borders] and stored in the green house in plastic tubes [thrips-proof mesh and sticky pads] and the emergence of thrips was recorded. A few thrips emerged only from soils collected from the outside the field and borders [2009]. This work will continue during 2010.<br /> <br /> Hosts within onion fields before and after the onion growing season: Volunteer onion plants collected in early spring 2008 and 2009 tested positive for IYSV in ELISA tests although they were symptomless. Thrips collected from these volunteers will be tested for IYSV in collaboration with WSU [Hanus Lab]. <br /> <br /> Overwintering thrips on cull onions and cull abundance: In spring 2009, two onion samples were collected from large cull piles [one each from OR and ID] in Treasure Valley region to determine whether cull piles could be a source of onion thrips. Very few thrips [2 to 3 thrips/5 onions] could be collected and these will be tested for IYSV in collaboration with WSU [Hanus Lab]. <br /> <br /> Possible role of overwintering weeds: Several weeds which can thrive in autumn [October-November] and winter [Dec-Feb] were collected, and the number of thrips associated with these weeds were counted. There was no discernible pattern in the number of thrips associated with different weed species. Mean number of thrips per weed varied among the fields. The thrips collected will be tested for IYSV in collaboration with WSU [Hanus Lab]. Common groundsel [Senecio vulgaris], spiny sowthistle [Sonchus asper], Redstem filaree [Erodium cicutarium] shepherd's-purse [Capsella bursa-pastoris] are some of the common winter weeds encountered in Treasure valley. A list of winter weeds in this region is being compiled in collaboration with Clint Shock [OSU, OR].<br /> <br /> New York  Brian Nault, Cornell University, Geneva, NY - Performance of foliar-applied insecticides  Products that worked best against onion thrips included cyantraniliprole (HGW86 10OD), spinetoram (Radiant SC), spirotetramat (Movento) and abamectin (Agri-Mek 0.15EC). Section 18s for Movento and Agri-Mek were granted by EPA in 2009 in New York; Section 18s for these products were submitted in early 2010 in New York. <br /> <br /> Performance of new insecticides when tank mixed with fungicides containing spreader stickers. Movento and Agri-Mek did not consistently work as well when tank mixed with fungicides that contained spreader stickers. The concern is that the spreader stickers in the fungicide formulation is interfering with the penetrant used to assist getting the insecticide into the plant tissue. There is also concern that the penetrant may allow the fungicide to enter plant tissues to cause phytotoxicity. Research is needed in 2010 to resolve this issue.<br /> <br /> Action thresholds for new products  Although Movento and Agri-Mek controlled the thrips population when applied following a 3 thrips larvae per leaf threshold, these results may not be applicable in a bad thrips year. The thrips infestation was low for half the season due to cold and wet weather. Thus, until more research is conducted, growers should consider using a more conservative threshold such as 1 thrips larva leaf. This more conservative approach will be even more important if these products are tank mixed with fungicides and spreader stickers.<br /> <br /> Performance of at-plant treatments (seeded)  Fipronil (Regent) applied in the furrow as a drench treatment was the only one that reduced the onion thrips infestation. Products that did not work included imidacloprid (Admire Pro), clorantraniliprole (Coragen) and cyantraniliprole (HGW86). Unfortunately, it is not likely that Regent will ever be labeled for use on onion.<br /> <br /> Impact of nitrogen on thrips - Nitrogen levels affected the size of larval populations in our onion plantings. The more nitrogen applied, the more larvae were found on plants with high nitrogen, indicating that either more eggs were laid on these plants, more larvae survived on these plants, or both. Research is planned to examine these thrips and nitrogen relationships further.<br /> <br /> Iris yellow spot virus in New York  After a significant increase in IYSV from 2007 to 2008 in the Elba Muck, the percentage of onions infected in 2009 dropped to a level similar to that in 2007. We suspect that the lower levels of IYSV were a consequence of a mild thrips season.<br /> <br /> We observed a significant reduction in bulb weight for onion plants (Red Bull and Milestone) infected with IYSV. On average, the reduction was about 0.1 lb for each cultivar. Because thrips damage was low to absent on these plants and did not differ between those infected and not infected, we suspect that this yield difference is due to the virus. Interestingly, IYSV symptoms were also low to absent for plants that tested positive for IYSV using DAS-ELISA.<br /> <br /> Late in 2009, we did not detect IYSV in weed hosts (common burdock and dandelion) known to be hosts for both IYSV and onion thrips. Again, we attribute this to a mild year for onion thrips.<br /> <br /> Oregon - Lynn Jensen, Clint Shock, Erik Feibert, and Monty Saunders, Oregon State University, Ontario, OR - Management factors such as irrigation, fertilization, and straw mulching that reduce plant stress might reduce the intensity of thrips and IYSV infestations. The management trials test the response of four onion cultivars to water stress level, irrigation system, and nitrogen fertilizer rate. Soil temperature and soil water potential was monitored in all treatments. Onions were rated for many economic parameters, thrips, IYSV symptoms, and ELISA. <br /> <br /> The combined effects of variety, irrigation system, irrigation criterion, and nitrogen (N) rate on IYSV expression and onion yield and grade were evaluated in 2008. N fertilization at 224 kg/ha failed to improve disease incidence or yield over 112 kg/ha. Drier irrigation criteria (30 kPa) resulted in more severe IYSV symptoms and lower marketable, colossal, and colossal plus super-colossal bulb yield than the wetter irrigation criteria. There were no significant interactions between variety, irrigation criteria, and N rate either year. Some varieties demonstrated tolerance with clearly different performance in the presence of IYSV. Kaolin foliar treatments failed to suppress IYSV.<br /> <br /> Screening insecticides for those with efficacy against thrips and those which reduce the impact of IYSV were conducted. Formetanate hydrochloride and spirotetramat were two compounds that are not yet registered for use in onion that seem to be very effective in controlling thrips and reducing the incidence of iris yellow spot virus. They were particularly effective when applied in a rotation with other insecticides such as methomyl and spinetoram. <br /> <br /> Washington  Hanu Pappu, Washington State University, Pullman, WA - Biological studies on IYSV - Studies on biological characteristics of the virus have been limited due to difficulties in obtaining consistent and reproducible mechanical transmission and lack of indicator hosts. Several plant species were evaluated for their response to mechanical inoculation with IYSV. The following seedlings were used: Arabidopsis thaliana COL 1, Capsicum annuum (Serrano pepper), Chenopodium quinoa, Datura innoxia, D. ferox, D. stramonium, Nicotiana benthamiana, N. tabacum, Solanum melongena and Vigna unguiculata (Heirloom variety). Infection was verified by symptoms, ELISA and RT-PCR of inoculated, and younger, non-inoculated leaves. In N. benthamiana, chlorotic local lesions appeared 7 to 10 days post inoculation (DPI) which subsequently expanded leading to drying of leaves by 20-25 DPI. The virus spread systematically showing severe veinal necrosis and some stem necrosis. D. stramonium showed 25-30 small chlorotic local lesions initially of 2-5 mm 10 to 12 DPI. The numbers of local lesions gradually increased and spread throughout the leaves within 20-25 days, and as the lesions coalesced the leaves dried 35-40 DPI. Infection remained localized. In V. unguiculata, symptoms appeared as diffuse and small necrotic spots in inoculated leaves 5 to 6 DPI. Chlorotic and necrotic ring spots developed in the inoculated leaves of C. annuum, which gradually increased in size and C. quinoa produced small concentric chlorotic rings spots,. Only the inoculated leaves were positive for IYSV in ELISA and RT-PCR, and no systemic infection could be seen. A. thaliana COL 1, D. innooxia, D. ferox, N. tabacum and S. melongena were symptomless and were negative for IYSV when tested by DAS-ELISA. There are no reports of natural infection of C. annuum by IYSV although C. annuum is a host for several other tospoviruses. Our studies showed that C. annum could be experimentally infected with IYSV.<br /> <br /> Molecular characterization of IYSV - The structure and organization of the large (L) RNA of Iris yellow spot virus (IYSV) was determined, and with this, the complete genomic sequence of IYSV has been elucidated. The L RNA was 8880 nucleotides in length and contained a single open reading frame (ORF) in the viral complementary (vc) strand. The primary translation product of 331.17 kDa shared many of the features of the viral RNA-dependent RNA polymerase (RdRp) coded by L RNAs of known tospoviruses. The 5$B!l(B and 3$B!l(B termini of IYSV L RNA (vc) contain two untranslated regions of 33 and 226 nucleotides, respectively, and both termini have conserved terminal nucleotides, another common feature of tospovirus genomic RNAs. Conserved motifs characteristic of RdRps of members of Bunyaviridae were present in the IYSV RdRp. These included DxxKWS (motif A); QGxxxxxSS (motif B); SDD (motif C); K (motif D); and EFxSE (motif E), Furthermore, three motifs TDF (Motif F1); KxQRTK (Motif F2) and DREIY (Motif F3) found in the RdRp of Capsicum chlorosis virus (CaCV) were also found in the IYSV RdRp. Phylogeny showed that the RdRp of IYSV is closer to the Eurasian group of tospoviruses: Tomato zonate spot virus from China, Watermelon silver mottle virus from Taiwan, CaCV from Thailand, Groundnut bud necrosis virus from India, and Melon yellow spot virus from Japan, whereas Tomato spotted wilt virus and Impatiens necrotic spot virus formed a different cluster (American), similar to that observed with the medium and small RNAs of IYSV and other tospoviruses.<br /> <br /> New strategies for understanding the seasonal dynamics of thrips vectors - IYSV is exclusively spread by thrips and there is no evidence of virus transmission through seed. Hence, infected plants and viruliferous thrips are the primary source and means of virus spread. There are limited options available for managing IYSV outbreaks. The ability to rapidly and accurately detect IYSV in thrips vectors for the purpose of estimation of the proportion of viruliferous thrips (=transmitters) from the field could potentially provide information that would be useful in more effective thrips management practices. A polyclonal antiserum was produced to the recombinant, E. coli-expressed nonstructural protein (NSs) coded by the small (S) RNA of IYSV. The recombinant fusion protein was obtained in the insoluble fraction, purified using a nickel column, and was used for the immunization of rabbits. When used in an antigen-coated plate ELISA, the antiserum, diluted up to 1:4,000, could detect the virus in a single adult thrips and in plants. Availability of antiserum to a non-structural protein of IYSV would be useful in epidemiological studies to better understand the role of thrips vectors in outbreaks of this important virus of onion.<br /> <br /> Effect of selected cultural practices in suppressing Iris yellow spot virus in onion - It is not known if management factors such as irrigation and fertilization that reduce plant stress might reduce the impact of IYSV . The combined effects of variety, irrigation system, irrigation criterion, and N rate on IYSV expression and onion yield and grade were evaluatedin 2007 and 2008. Fertilization at 112 kg N/ha resulted in a higher onion yield and grade in 2007 than 224 kg N/ha. There were no differences in onion yield or grade between N rates in 2008, but failed to influence disease incidence either year. Symptoms were fewer in 2007 and no significant differences between treatments were observed. In 2008, averaged over varieties and N rates, drier irrigation criteria (higher SWT) resulted in significantly more severe IYSV symptoms. Averaged over varieties and N rates, drip irrigation at 30 kPa resulted in significantly lower marketable, colossal, and colossal plus supercolossal bulb yield than the wetter irrigation criteria in both 2007 and 2008, but the differences were more pronounced in the presence of IYSV in 2008. There were no significant interactions between variety, irrigation criteria, and N rate either year.<br /> <br /> Objective 3. Transfer information on progress dealing with IYSV and thrips biology and IPM strategies to the onion industry and other interested parties<br /> <br /> New York  Brian Nault, Cornell University, Geneva, NY - Several meetings were held in 2009 to inform NYs onion industry about results from this project: the Annual Winter New York Onion Industry Council Meeting in Ithaca in January, the Empire State Fruit and Vegetable EXPO in Syracuse in February, the Onion School in Middletown in March, the Oswego Twilight Meeting in June, the Annual Summer New York Onion Industry Council Meeting in Potter in July and the Elba Muck Onion Meeting in Elba in August. Additionally, an annual workshop was held in Ithaca that included a session to update Cornell Cooperative Extension Educators about results from this project. <br /> <br /> Information pertaining to this subject was also presented at the Sixth International IPM Conference in Portland, OR, the Ninth International Symposium on Thysanoptera and Tospoviruses on the Gold Coast of Australia and the Annual Entomological Society of America Meeting in Indianapolis, IN.<br /> Oregon - Lynn Jensen, Clint Shock, Erik Feibert, and Monty Saunders, Oregon State University, Ontario, OR - Results have been effectively communicated by fieldmen and grower participation in project planning and evaluation of results. Nine instructional events including classroom instruction and field tours were held for growers and fieldmen. These events were presented on May 19, June 30, July 8, Aug 3, Aug 25, Aug 28 and Dec 11. In addition, information was presented at grower meetings in February 2009, internet web sites, and results being retold by the reporters of Onion World.<br />

Publications

Publications<br /> Bag, S., and H.R. Pappu. 2009. Symptomatology of Iris yellow spot virus in selected indicator hosts. Plant Health Progress. doi:10.1094/PHP-2009-0824-01-BR.<br /> <br /> Bag, S., J. Singh, R.M. Davis, W..Chounet, and H.R. Pappu. 2009. Iris yellow spot virus in Nevada and Northern California. Plant Disease 93:674.<br /> <br /> Bag, S., K.L. Druffel, T. Salewsky, and H.R. Pappu. 2009. Nucleotide sequence and genome organization of the medium RNA of Iris yellow spot virus (genus Tospovirus, family Bunyaviridae) from the United States. Archives of Virology 154:715-718.<br /> <br /> Bag, S., P. Rogers, R. Watson, and H.R. Pappu. 2009. First report of natural infection of garlic (Allium sativum) with Iris yellow spot virus in the United States. Plant Disease 93:839.<br /> <br /> Diaz-Montano, J., M. Fuchs, B. A. Nault and A. M. Shelton. 2010. Evaluation of onion cultivars for resistance to onion thrips (Thysanoptera: Thripidae) and Iris yellow spot virus. J. Econ. Entomol. (in press).<br /> <br /> Evans, C.K., S. Bag, E. Frank, J. Reeve, C. Ransom, D. Drost, and H.R. Pappu. 2009. Natural infection of Iris yellow spot virus in Twoscale saltbush (Atriplex micrantha) growing in Utah. Plant Disease 93:430.<br /> <br /> Evans, C.K., S. Bag, E. Frank, J. Reeve, C. Ransom, D. Drost, and H.R. Pappu. 2009. Green foxtail (Setaria viridis), a naturally infected grass host of Iris yellow spot virus in Utah. Plant Disease 93:670.<br /> <br /> Hsu, C., C. A. Hoepting, M. Fuchs, A. M. Shelton and B. A. Nault. 2010. Temporal dynamics of Iris yellow spot virus and its vector, Thrips tabaci (Thysanoptera: Thripidae), in seeded and transplanted onion fields. Environ. Entomol. (in press).<br /> <br /> Multani, P.S., C.S. Cramer, R.L. Steiner, and R. Creamer. 2009. Screening winter-sown onion entries for Iris yellow spot virus tolerance. HortScience 44:627-632.<br /> <br /> Pappu, H.R., R.A.C. Jones, and R.K. Jain. 2009. Global status of tospovirus epidemics in diverse cropping systems: Successes gained and challenges that lie ahead. Virus Research 141:219236. <br /> <br /> Schwartz, H. F. Gent, D. H., Fichtner, S. M., Hammon, R., Cranshaw, W. S., Mahaffey, L., Camper, M., Otto, K., and McMillan. 2009. Straw mulch and reduced-risk pesticide impacts on thrips and Iris yellow spot virus on western-grown onions. Southwestern Entomologist 34:13-29. <br /> <br /> Nault, B. A. 2009. Controlling onion thrips with insecticides. The IX International Symposium on Thysanoptera and Tospoviruses. Main Beach, Queensland, Australia. September 4, 2009.<br /> <br /> Nault, B. A. 2009. Ecology of onion thrips and epidemiology of Iris yellow spot virus: Implications for management in New York onion fields. The IX International Symposium on Thysanoptera and Tospoviruses. Main Beach, Queensland, Australia. September 1, 2009. <br /> <br /> Sampangi, R.K, S.K. Mohan and H.R. Pappu 2009. Weed hosts of Iris Yellow Spot Virus [IYSV] and implications for disease management in onion crops in the U.S. Pacific Northwest. Intl. Conf. on Plant Pathology in Globalized Era New Delhi, India [Nov.2009]<br /> <br /> Schwartz, H. F. 2009. Thrips and IYSV management in Colorado onion production systems. Key Note Speaker at a special symposium for northern Mexico onion growers and industry on Onion IYSV and Thrips in Delicias, Chihuahua, Mexico on September 2, 2009. The symposium was sponsored by various agricultural agencies and private industries. <br /> <br /> Shock, C.C., E.B.G. Feibert, L.D. Saunders, L.B. Jensen, H.R. Pappu, S.K. Mohan, and R.S. Sampagni. 2009. Effect of selected cultural practices in Suppressing Iris yellow spot virus in Onion. IX International Symposium on Thysanoptera and Tospoviruses, 31 August  4 September 4 2009, Sea World Resort, Gold Coast, Queensland, Australia.<br /> <br /> Cramer, C.S. Screening onion plant introduction accessions for Iris yellow spot virus resistance. National Onion Association Annual Convention. San Antonio, TX. Dec. 2-5, 2009.<br /> <br /> Cramer, C.S. Screening winter-sown onion entries for Iris yellow spot virus resistance. W1008: Biology and management of Iris yellow spot virus (IYSV) and thrips in onions. Regional research project annual meeting. San Antonio, TX. Dec. 3, 2009.<br /> <br /> Diaz-Montano, J., B. A. Nault, M. Fuchs and A. M. Shelton. 2009. Characterization of resistance to onion thrips (Thrips tabaci Lindeman) and incidence of Iris yellow spot virus in onion cultivars. Entomological Society of America Annual Meeting, Indianapolis, IN. (Note: Awarded second place in Student Competition for the Presidents Prize in the Section Plant-Insect Ecosystems: Host Plant Interaction, Resistance).<br /> <br /> Hoepting, C., M. L. Hessney and B. A. Nault. 2009. Onion thrips management update: New York. W-1008 Annual Meeting. San Antonio, TX. December 3, 2009.<br /> <br /> Hsu, C. L., C. Hoepting, A. Shelton and B. A. Nault. 2009. New York update on onion thrips and Iris yellow spot virus research. W-1008 Annual Meeting. San Antonio, TX. December 3, 2009.<br /> <br /> Hsu, C. L., C. Hoepting, S. Reiners and B. A. Nault. 2009. Effects of nitrogen fertilizer rates on onion thrips (Thrips tabaci Lindeman) populations in the field. Entomological Society of America Annual Meeting, Indianapolis, IN.<br /> <br /> Schwartz, H. F. 2009. Update on national onion projects and impacts on the U.S. <br /> onion industry. Invited Speaker at the annual meeting of the National Onion Association on December 3, 2009 in San Antonio, TX. <br /> <br /> Shock, C.C., E.B.G. Feibert, L.D. Saunders, L.B. Jensen, H.R. Pappu, S.K. Mohan, and R.S. Sampagni. 2009. Cultural practices to reduce the expression of Iris Yellow Spot Virus. American Society of Horticultural Science Annual Conference, 25 - 28 July, 2009, St. Louis, Missouri.<br /> <br /> Smith, E. A., A. DiTommaso, C. L. Hsu, M. Fuchs, A. M. Shelton and B. A. Nault. 2009. Weed hosts of onion thrips (Thrips tabaci) and their role in Iris yellow spot virus epidemiology in onion. Entomological Society of America Annual Meeting, Indianapolis, IN. (Note: Awarded first place in Student Competition for the Presidents Prize in the Section Plant-Insect Ecosystems: Plant Resistance).<br /> <br /> Nault, B. A. 2009. Onion thrips control in New York. In Great Lakes EXPO Educational Program Abstracts. December 7-8, 2009. Grand Rapids, MI. Michigan State University Extension.<br /> <br /> Nault, B. A., C. Hsu, E. Smith, J. Diaz-Montano, M. L. Hessney, P. Marcella-Herrick, M. Fuchs, A. Shelton, A. DiTommaso and C. Hoepting. 2009. Onion thrips and Iris yellow spot virus in New York, pp. 62-66. In: Proceedings of the 2009 Empire State Fruit and Vegetable Expo. February 11-12, 2009. Syracuse, NY. Cornell Cooperative Extension and New York State Vegetable Growers Association.<br /> <br /> Nault, B. 2009. Control of onion thrips. Oswego County Onion Growers Twilight Meeting, Oswego, NY. June 17, 2009. Speaker, 45 minutes. Attendees: 80. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Nault, B. 2009. Do onion growers need to be concerned about Iris yellow spot virus? Elba Muck Onion Twilight Meeting, Elba, NY. July 29, 2009. Cornell Cooperative Extension. Speaker, 10 minutes. Attendees: 50. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Nault, B. 2009. New management strategies for controlling onion thrips. Elba Muck Onion Twilight Meeting, Elba, NY. July 29, 2009. Cornell Cooperative Extension. Speaker, 20 minutes. Attendees: 50. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Nault, B. 2009. Onion insect management with an emphasis on onion thrips. Onion School for Orange County Onion Growers. Middletown, NY. March 16, 2009. Speaker, 40 minutes. Attendees: 50. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Nault, B. 2009. Using spirotetramat (Movento) to manage onion thrips in onions. Movento Educational Meeting, Elba, NY. June 18, 2009. Speaker, 20 minutes. Attendees: 50. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Nault, B. A. 2009. Onion insect management and Iris yellow spot virus research update for 2009. Cornell Cooperative Extension Agriculture and Food Systems November In-Service, Ithaca, NY. November 10, 2009.<br /> <br /> Nault, B. A., C. Hsu, A. Shelton, M. Fuchs, A. Taylor, J. Diaz-Montano, E. Smith, and M. Hessney. 2009. Research summary on research on management of onion insect pests and Iris yellow spot virus. New York Onion Industry Council Winter Meeting, Ithaca, NY. January 21, 2009. Speaker, 30 minutes. Attendees: 20. Onion growers, CCE educators and Cornell faculty.<br /> <br /> Nault, B. and C. Hoepting. 2009. New developments in managing onion maggot in direct-seeded and transplanted onions. Elba Muck Onion Twilight Meeting, Elba, NY. July 29, 2009. Cornell Cooperative Extension. Speaker, 15 minutes. Attendees: 50. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Nault, B., C. Hsu, T. Shelton, M. Fuchs, E. Smith and J. Diaz-Montano, M. L. Hessney, S. Reiners and A. Taylor. 2009. Onion insect management and Iris yellow spot virus. New York State Onion Industry Council Summer Tour and Meeting, Potter, NY. July 23, 2009. Cornell Cooperative Extension. Co-speaker, 45 minutes. Attendees: 60. Onion growers, vegetable industry representatives, crop consultants, CCE educators and Cornell faculty.<br /> <br /> Schwartz, H. F. 2009 Onion virus management and updates. Annual Education Meeting of the Colorado Onion Association on January 29, 2009 at Eaton, CO <br /> <br /> Shock, C.C. and E.B.G. Feibert*. 2009. Irrigation, fertilization, and cultivar to manage IYSV. OSU Malheur Experiment Station Field Day, 8 July 2009, Ontario, OR.<br /> <br /> Shock, C.C. and E.B.G. Feibert. 2009. Cultural practice options to reduce IYSV risks. OSU Malheur Experiment Station Onion Variety Day, 25 August 2009, Ontario, OR.<br /> <br /> Shock, C.C. E.B.G. Feibert, L.D. Saunders, L.B. Jensen, S.K. Mohan, R.S. Sampangi, and H. Pappu. 2009. How Do IYSV and Cultural Practices Affect Onion Performance? 48th Annual Meeting of the Malheur Onion Growers Association and Idaho Onion Growers Association, 3 February 2009, Ontario, OR. <br /> <br /> Nault, B. A. 2009. Cornell team looks at onion thrips and Iris yellow spot virus in New York. Onion World. 25(4): 6-8.<br /> <br /> Nault, B. A. and A. M. Shelton. 2009. Onion thrips management: New insecticides and timing strategies. Cornell University Cooperative Extension Vegetable Program. Veg Edge 5(7): 10-11.<br /> <br /> Jensen, L., C.C. Shock, and L.D. Saunders. 2009. 2008 Managing insecticides for maximum efficacy against thrips in dry bulb onions. Oregon State University Agricultural Experiment Station, Special Report 1094:67-76. http://www.cropinfo.net/AnnualReports/2008/ManagingInsecticidesForMaximumEfficacyOnions.html<br /> <br /> Jensen, L.B. 2009. 2008 Insecticide efficacy trial for thrips in control in dry bulb onions. Oregon State University Agricultural Experiment Station, Special Report 1094:61-66. http://www.cropinfo.net/AnnualReports/2008/InsecticideEfficacyTrialsForThripsInOnions.html<br /> <br /> Onion Disease Management strategies, reports and publications, including those on IYSV and thrips. http://www.colostate.edu/Orgs/VegNet/vegnet/onions.html <br /> <br /> Schwartz, H. F. 2009. Web site dedicated to information and resources on onion pest management and/or thrips and IYSV. http://www.alliumnet.com/index.htm <br /> <br /> Shock, C.C. E.B.G. Feibert, and L.D. Saunders. 2009. Performance of onion varieties in a field with high iris yellow spot virus presence. Oregon State University Agricultural Experiment Station, Special Report 1094:29-31. http://www.cropinfo.net/AnnualReports/2008/PerformanceOfOnionVarietiesWithHighIrisYellowSpotVirusPresence.html<br /> <br /> Shock, C.C., E.B.G. Feibert, L.D. Saunders, L.B. Jensen, S.K. Mohan, R.S. Sampagni, and H.R. Pappu. 2009. Management of onion cultural practices to control the expressions of iris yellow spot virus. Oregon State University Agricultural Experiment Station, Special Report 1094:41-60. http://www.cropinfo.net/AnnualReports/2008/ManagementOfOnionPracticesToControlTheIrisYellowSpotVirus.html<br /> <br /> Shock, C.C., E.B.G. Feibert, L.D. Saunders, L.B. Jensen, S.K. Mohan, and H.R. Pappu. 2009. 2008 Onion variety trials. Oregon State University Agricultural Experiment Station, Special Report 1094:20-28. http://www.cropinfo.net/AnnualReports/2008/2008OnionVarietyTrials.html<br /> <br /> Other Activities<br /> <br /> Submitted a package to the New York State Department of Environmental Conservation for their consideration of a Specific Emergency Exemption (FIFRA Section 18) for the use of spirotetramat (Movento) on onion for onion thrips control for the 2009 season. The Crisis Exemption request was granted by NYSDEC from June- September 2009.<br /> <br /> Submitted a package to the New York State Department of Environmental Conservation for their consideration of a Specific Emergency Exemption (FIFRA Section 18) for the use of abamectin (Agri-Mek 0.15EC) on onion for onion thrips control for the 2009 season. The Crisis Exemption request was granted by NYSDEC from June- September 2009.<br /> <br /> Submitted a package to the New York State Department of Environmental Conservation for their consideration of a Specific Emergency Exemption (FIFRA Section 18) for the use of formetanate hydrochloride (Carzol SP) on onion for onion thrips control for the 2009 season. The Crisis Exemption request was NOT granted by NYSDEC<br />

Impact Statements

1. Colorado results will be used by national onion industries, growers, seed company breeders and pathologist, and integrated pest management specialists to select more effective management strategies including the promotion of varieties that are less susceptible to damage by thrips and the virus.
2. More growers are adopting drip irrigation and adopting careful irrigation scheduling resulting in irrigated onion crops that suffer less injury from IYSV.
3. Research at Cornell University has identified new and selective insecticides and strategies to apply them enabling growers to keep onion thrips populations under control during the 2009 growing season. By following Cornell recommendations, it was possible for onion growers to decrease the frequency of sprays and reduce the number of insecticide sprays applied per season.
4. Three years of epidemiological and IYSV sources studies have ruled out the likelihood that imported bare root transplants, volunteer onions (when rogued out of onion fields in a timely manner) and bulbs from out of state are major sources of IYSV in New York.

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Report Information

Participants

Lee Sommers, Colorado State University, lee.sommers@colostate.edu;Brent Clement, Onion World, dbclement65@gmail.com;Steven Beer, Cornell Plant Path, Ithaca, svb1@cornell.edu;Chris Cramer, New Mexico State University, cscramer@nmsu.edu;Robert T. Sakata, Sakata Farms, rtsakata@aol.com;Howard F. Schwartz, Colorado State University, howard.schwartz@colostate.edu;Stuart Reitz, USDA-ARS, stuart.reitz@ars.usda.gov;Heleen Bukman, Bejo Zaden, h.bukman@bejo.nl;Mary Ruth McDonald, University of Guelph, mrmcdona@uoguelph.com;Silvamani Sundaray, University of Georgia, sivamani@uga.edu;Juan Carlos Brevis, Enza Zaden , juan.brevis@enzausa.com;Shannon Pike, Enza Zaden , shannon.pike@enzausa.com;Steve McArthur, Vigour, steve@vigour.co.nz;David O'Connor, Allium & Brassica Ctr. Ltd., abcenter@aol.com;Mike Derie, Washington State University, derie@wsu.edu;Kaz Tsutsui, Shippo Seed Company, onion@ruby.ocn.ne.jp;Takashi Iwata, Kagana University, choror-2000jp@yahoo.co.jp;Satoshi Iwata, Yamaguchi University, k007gd@yamaguchi-u.ac.jp;Jim Lorbeer, Cornell University, jwls@cornell.edu;Agustin Agraz, OLAM Spices & Vegetables, cornucopia72@hotmail.com;Cesar Saray, OLAM Spices & Vegetables, cesar.saray@olamnet.com;George Malm, OLAM Spices & Vegetables, george.malm@olamnet.com;Dan Maclean, University of Georgia, dmaclean@uga.edu;Shane Shelton, Tanimura & Antle, shane@taproduce.com;Clint Shock, Oregon State University, clinton.shock@oregonstate.edu;Charles Webber, USDA-ARS, cwebber-usda@lane-ag.org;Phil Sarasqueta, Bayer Crop Science, phil.sarasqueta@bayer.com;Mike Bowman, Nunhems (USA), mike.bowman@bayer.com;Joel Canestrino, NiZ-HAG, jcanestrino@hazerainc.com;Charles Boateng, Colorado State University, cobakgh@yahoo.com;Jagtar Singh, Peri & Sons Farms, jagtar@periandsons.com;Neel Kamal, Monsanto Vegetable Seeds, neel.kamal@monsanto.com;Beth Gugino, Pennsylvania State University, bkgunino@psu.edu;David Whitwood, Crookham Company, davew@crookham.com;Peter Boches, Nunhems , peter.boches@bayer.com;Rick Watson, Nunhems, rick.watson@bayer.com;Rene Emch, Nunhems, rene.emch@bayer.com;Jim Christopherson, L & L Ag Production, LLC, jim@llagprod.com;Kerrick Bauman, L & L Ag Production, LLC, kerrick@llfarms.com;Kevin Kudsh, L & L Ag Production, LLC, kevin@llfarms.com;Michael Havey, USDA - University of Wisconsin, mjhavey@wisc.edu;Andrew Taylor, University of Warwich, andrew.taylor@warwick.ac.uk;Stephanie Szostek, Colorado State University, stephasp@rams.colostate.edu;Mike Bartolo, Colorado State University, michael.bartolo@colostate.edu;Kent Welsh, OLAM Spices & Vegetables, kent.welsh@alomnet.com;Dan Drost, Utah State University, dan.drost@usu.edu;Andres Casas, Univ. Nac. Agrario-La Molina, cda@lamolina.edu.pe;Christy Hoepting, Cornell Cooperative Extension, cah59@cornell.edu;Brian Nault, Cornell University, ban6@cornell.edu;Erik Smith, Cornell University, eas56@cornell.edu;Cynthia Hsu, Cornell University, clh33@cornell.edu;John Calandri, Son Rise Farms, donna@calandrisonrisefarms.com;Mark Proutor, DST, Inc, dstincorp@aol.com;Cloudia Nischwitz, Utah State University, claudia.nischwitz@usu.edu;Ron Gitaitis, University of Georgia, dronion@uga.edu;;

Brief Summary of Minutes

Accomplishments

Objective 1. Screen onion germplasm for improved levels of tolerance to Iris yellow spot virus (IYSV) and thrips <br /> <br /> Colorado Howard Schwartz, Colorado State University, Ft. Collins, CO - During 2010 the Colorado team identified the following germplasm with significantly greater plant vigor after season-long exposure to thrips and the virus: Plant Introduction (PI) lines 258956,264320, 546140, 546188 and 546192. These lines were selected as candidates for the translational genomics study coordinated by colleagues involved with the USDA-SCRI Project 2008-04804. The evaluation design verified that screening nurseries planted in fields with a history of problems from onion thrips and IYSV could provide moderate to severe pest and disease pressure to enable the identification of less susceptible onion entries (varieties, breeding lines or germplasm).<br /> <br /> New Mexico Chris Cramer, New Mexico State University, Las Cruces, NM - Forty-eight onion plant introduction (PI) accessions from the U.S. germplasm collection and 32 intermediate- and long-day commercial cultivars and experimental breeding lines from the New Mexico State University breeding program were evaluated for the number of thrips per plant, leaf color, leaf waxiness, leaf axil pattern, Iris yellow spot (IYS) disease symptoms, and bulb yield. Of those PI accessions that had not matured yet, thrips number per plant was highest at 12 weeks post transplanting while the number decreased afterwards up to 16 weeks. At 12 weeks, plants of PI 165498 had fewer thrips per plant than plants of other accessions. For the commercial cultivars and experimental breeding lines tested, thrips number per plant was similar at 12, 16, and 20 weeks. At 12 weeks, there were very few differences in thrips number per plant among entries. At 16 weeks, plants of NMSU 07-54-1 had fewer thrips per plant than plants of other entries. At 20 weeks, plants of Early Red Burger, NMSU 07-56-2, NMSU 07-57-2, Stockton Early Yellow, and Stockton Red averaged less than 10 thrips per plants and had fewer thrips per plants than plants of most other entries.<br /> <br /> Twelve accessions were rated as having light to dark green leaf color, three were rated as having semi-glossy to glossy leaves, and one possessed an open leaf axil pattern. PI 165498, PI 258956, and PI 264320 possessed semi-glossy foliage that was dark green in color. Most of the commercial cultivars and experimental breeding lines tested were rated as having leaves that were light to dark green in color. Plants of 07-54-1 were rated as having glossy leaves while 39 entries were rated as having semi-glossy leaves. There were no differences in leaf axil pattern among the entries tested in this group. At 16 weeks, PI 249899, PI 288073, and PI 391509 exhibited less severe IYS symptoms than other accessions. For the commercial cultivars and experimental breeding lines tested, IYS disease severity was low generally for most entries at 16 weeks. Disease symptoms became more severe by 20 weeks. At this time, NMSU 08-43, NMSU 07-54-1, and NMSU 09-58 expressed IYS symptoms that were less severe than symptoms observed on plants of other entries. The disease incidence at 16 weeks was lower for NMSU 07-33-1, NMSU 09-58, and NuMex Centric than other commercial cultivars and experimental breeding lines. Of the accessions tested, PI 264320 and PI 546100 exhibited a jumbo market class yield that was greater than the yield of other entries. Of commercial cultivars and experimental breeding lines tested, NMSU 07-30-2, NMSU 07-32-2, NMSU 07-33-1, NMSU 07-54-1, NMSU 09-58, and SBO 5508 exhibited a jumbo market class yield that was greater than the yield of other entries. Individual plants, that exhibited few IYS disease symptoms, were selected at bulb maturity from 4 different experimental breeding lines for a total of 7 bulbs. These bulbs are being self-pollinated in the hopes of finding individual progeny that possess a higher level of IYS tolerance. In addition to the onion germplasm being screened, several onion-related Allium species were also screened for tolerance to Iris yellow spot virus. A. altaicum, A. galanthum, A. schoenoprasum, and A. tuberosum developed mild IYS disease symptoms and were confirmed to be positive for IYSV by ELISA. A. roylei and A. vavilovii developed severe IYS disease symptoms and were confirmed to be positive for IYSV.<br /> <br /> New York Brian Nault, Anthony Shelton and John Diaz-Montano, Cornell University, Geneva, NY - The effect of leaf color on onion thrips preference was investigated. The reflectance spectrum of leaves from 11 onion-thrips resistant cultivars, along with 6 other cultivars, was measured using a spectrometer to determine if color and/or light reflectance were associated with resistance to T. tabaci. Two susceptible cultivars had the highest values of leaf reflectance in the first (275-375nm) and second (310-410nm) theoretical photopigment-system of T. tabaci and these values were significantly different from most resistant cultivars. Because the two susceptible cultivars always had the highest number of thrips compared with the resistant onion cultivars in previous studies, these results suggest a strong response of T. tabaci to onion cultivars with higher light reflectance in the UV range (270-400nm). If genes that confer leaf color are identified they could be integrated in onion breeding programs to develop plants that would elicit behavioral responses by T. tabaci that would result in non-preference for onion cultivars. <br /> <br /> Steven Beer reported on the biology of Pantoea ananatis and the center rot disease that it causes in onions. Earlier, we had documented that this bacterial pathogen occurs in onions in New York and is responsible for considerable damage to the onion crop. The connection to W1008 is that thrips are suspected to vector the pathogen. Thrips that are common in Georgia onion-growing areas are tobacco thrips, Thrips tabaci. These thrips have been implicated as vectors of P. ananatis, based on finding the bacterium in the gut of thrips. However, the thrips common in New York onions are onion thrips, Frankliniella fusca. Their role as vectors of the center rot pathogen is hypothesized, but not documented or proven. In earlier work in New York, P. ananatis was confirmed as the cause of center rot in onions that had been stored by growers for 4 to 6 months following harvest. More recently, we documented the presence of the pathogen in symptomatic mid-season growing onions. Thus, apparently the pathogen that results in unmarketable stored onions begins to develop in the field. Furthermore, this relationship was confirmed experimentally by inoculating growing onions in the greenhouse and following the development of the infection over several weeks from leaves, to the neck and into the corresponding bulb scales. <br /> <br /> In limited analyzes of thrips collected from onion foliage, we identified strains of P. ananatis. The center rot pathogen was present on the exteriors of thrips. No strains of were detected in the homogenates of a limited number of surface-disinfested thrips that were analyzed. However, further analyses are indicated before reaching a definite conclusion in regard to the possible presence of P. ananatis in the gut of Frankliniella fusca. Prior to and during the 2010-growing season in New York, we endeavored to determine possible sources of inoculum of P. ananatis. Thus, in collaboration with Cornell Cooperative Extension Educators, we collected samples of onion seed, transplants and muck soil. These materials were plated or otherwise extracted for P. ananatis using an onion extract medium (OEM) that we developed; several well-described pathogens of onion grow well on OEM. Pantoea ananatis was discerned from a few samples of soil. However, there was no clear source of inoculum that explained the rather widespread distribution of center rot seen in onions following storage. Inoculation of sets with toothpicks contaminated with test bacteria proved to be a rapid and effective means of testing for the symptoms induced by some, but not all, strains of these bacterial pathogens.<br /> <br /> Oregon - Lynn Jensen, Clint Shock, Erik Feibert, and Monty Saunders, Oregon State University, Ontario, OR - The onion trials were conducted in 2008, 2009, and 2010 as planned. Results from 2008 and 2009 trials have been compiled and distributed to growers and the public. Onions from the 2010 season and stored in the 2010-2011 storage season are being graded and the data will be analyzed, reported, and published in the near future. Based on the first two years of the project, preliminary results indicate the following: Based on on farm and on station trials, onion varieties have been identified that are more and less tolerant to IYSV. The 2009 onion variety trial strongly sorted varieties for IYSV since the infection rate was severe. Irrigation systems and irrigation criteria have been tested as planned.<br /> <br /> Washington Hanu Pappu, Washington State University, Pullman, WA - Varietal trials. In cooperation with Clint Shock at Oregon State determined the virus levels using ELISA to see if there is any correlation between host response to natural infection by the virus under field conditions (=symptom expression) and virus levels as determined by ELISA.<br /> <br /> Objective 2. Study the biology and epidemiology of IYSV and thrips, and impacts of chemical, cultural and biological tactics that can reduce their impacts upon onions. <br /> <br /> Colorado Howard Schwartz, Colorado State University, Ft. Collins, CO - Two populations of Thrips tabaci infested with Iris yellow spot virus (IYSV) were reared on either radish (Alta Globe variety) or onion plants (grown from Gurney's yellow onion sets). Plant and thrips samples were removed at two week intervals for twelve weeks and IYSV presence was monitored by PCR. Thrips reared on onion retained IYSV over subsequent generations, while thrips reared on radish lost the virus. This method of generating IYSV-free T. tabaci may be useful in comparative studies between IYSV-infected and IYSV non-infected T. tabaci. Quantitative Real Time Reverse Transcriptase PCR (QRT-RT-PCR) can be used to quantify the amount of IYSV nucleoprotein genes at different points within the onion plant. Preliminary data shows that the amount of IYSV nucleoprotein gene present in 2 cm leaf samples taken from symptomatic onion leaves varies along the length of the leaf, with the highest concentration of IYSV at the lesion.<br /> <br /> There was no cultivar difference for either onion bulb weight or bulb size in a thrips and IYSV study in the greenhouse. However, there was significant treatment difference for weight (probability less than 0.0001), with the Healthy Control giving the highest bulb weight of 0.128 pounds per bulb, followed by Virus infection only plants with 0.08 pounds per bulb, then Thrips only with 0.044 pounds per bulb and finally Thrips plus Virus infected plants with 0.031 pounds per bulb. There also was a significant bulb size difference between the treatments (probability less than 0.001) with Healthy Control having the largest bulb diameter of 1.77 inch, followed by Virus, then Thrips and finally by Thrips plus Virus with sizes 1.61, 1.38 and 1.22 inches, respectively.<br /> <br /> Oregon - Lynn Jensen, Clint Shock, Erik Feibert, and Monty Saunders, Oregon State University, Ontario, OR - Small increments of water stress on onion were very detrimental to onion yield and grade in the presence of IYSV in 2008. In 2009 the IYSV pressure at the irrigation trial site was less than in 2008 and the effects of water stress were less dramatic. Additional growers are adopting drip irrigation systems and carefully monitoring soil water tension. The growers notion that sprinkler irrigation would aid in the reduction of onion thrips has not been substantiated. There seems to be no difference in thrips pressure between irrigation systems. Consistent with the results from 2008, extra N fertilizer in 2009 was not of any benefit to help onions continue growing in the presence of IYSV. No interactions have yet been observed between varieties, water stress, and N fertilizer rates. On farm attempts to reduce IYSV effects through the application of kaolin clay have not been successful and growers have stopped trying this option. <br /> <br /> Florida Stuart Reitz, USDA-ARS, Tallahasse, FL - Kaolin can increase UV reflectance, which has been shown to repel Frankliniella thrips. Field trials were conducted to determine if kaolin could reduce thrips damage in onion in the southeastern USA, where tobacco thrips Frankliniella fusca and onion thrips Thrips tabaci are the most common species. Significantly more thrips, primarily F. fusca, were found on untreated onion. Also, the end of season evaluation of feeding damage showed kaolin treated plants had significantly less damage than did untreated plants (Fig. 1) and had lower incidence of purple blotch. Spray coverage was not uniform, but did exceed 70% of the leaf surface area. In the absence of rainfall, kaolin tended to persist on onion foliage, with no decrease in residue from 1 to 5 days after treatment.<br /> <br /> Idaho Krishna Mohan and R.K. Sampangi, University of Idaho, Parma, ID  Thrips samples collected from the overwintering onions, cull piles and overwintering weeds from different locations during 2009-2010 are awaiting analysis in Dr. Hanu Pappus (WSU) laboratory. We are collaborating with Dr. Clint Shock (MES, OSU) on the Western SARE project to evaluate the effect of selected cultural practices in suppressing IYSV symptom severity in onion.<br /> <br /> New York Brian Nault, Cornell University, Geneva, NY - Performance of foliar-applied insecticides  Products that worked best against onion thrips included spinetoram (Radiant SC), spirotetramat (Movento), cyantraniliprole (HGW86 10OD) and abamectin (Agri-Mek 0.15EC). Section 18s for Movento and Agri-Mek were granted by EPA in 2010 in New York; Section 18s for these products were submitted again and approved in early 2011 in New York. (a) Performance of new insecticides when tank mixed with fungicides containing spreader stickers. Inclusion of the fungicide, Chloronil, with Agri-Mek, Movento or Radiant as a tank mix reduced the efficacy of thrips control compared with using each insecticide without Chloronil. The reason for this phenomenon is not known. Results from this study also revealed that the reduction in thrips control that occurred when Chloronil was included in the tank mix can be mitigated if a penetrating surfactant is included. Therefore, a tank mix that includes the insecticide, Chloronil and a penetrating surfactant should provide an acceptable level of thrips control. More research is needed to determine if rate of the penetrating surfactant used in the insecticide and fungicide tank mix is important for controlling thrips. (b) Action thresholds for new products  Movento controlled the thrips population when applied following a 3 thrips larvae per leaf threshold, whereas an action threshold of no more than 1 thrips larva per leaf should be used for Agri-Mek. (c) Impact of nitrogen on thrips - Preliminary analyses of one of the fields confirmed the results found in the earlier experiment, plots receiving lower amounts of N fertilizer had significantly fewer larval onion thrips compared with plots receiving higher rates of N fertilizer. This may be due to possible negative effects that lower nitrogen levels in plant tissue could have on thrips colonization, reproduction, survival or emigration behaviors. Future analyses will estimate whether this reduction in larval populations can affect the number or timing of insecticide applications. Bulb weights were not significantly different between plots receiving 74-125 lbs N/ac. We found a higher number of total bulbs > 2 inches in diameter in the highest N treatments (data not shown) but final marketable yield estimates will not be calculated until bulbs placed in storage are graded for rot. There was a trend for higher levels of rot in sprayed plots that received the highest levels of N fertilizer, but the differences were not significant. We anticipate that the cumulative pre- and post-storage percentage of bulbs with rot will result in significant differences in rot levels between the N treatment plots. Final counts of marketable bulbs after subtracting bulbs with rot could eliminate differences in preliminary estimates of bulb yields between the higher N treatments. While more plants lodged earlier in the plots receiving the highest levels of N fertilizer, this did not appear to affect bulb weight, since the mean bulb weights were highest in the plots that had the highest percentage of plants that had lodged. The 2010 growing season was warm and onion plants matured sooner than usual resulting in almost no bulbs reaching large sizes (e.g. there were almost no jumbo-sized bulbs). This trial will be repeated 2011 and, in a cooler and longer growing season, plants that lodge sooner may affect final bulb weights. (d) Iris yellow spot virus in New York  Comparisons were made between number bulb yield of onions that tested positive and negative for IYSV using DAS-ELISA. In 2 of the 4 fields surveyed, bulb weight from infected plants was lower than weight from non-infected ones. No differences in bulb weight between IYSV-infected and non-infected plants were observed in the other two fields.<br /> <br /> Oregon - Lynn Jensen, Clint Shock, Erik Feibert, and Monty Saunders, Oregon State University, Ontario, OR - Management factors such as irrigation, fertilization, and straw mulching that reduce plant stress might reduce the intensity of thrips and IYSV infestations. The management trials test the response of four onion cultivars to water stress level, irrigation system, and nitrogen fertilizer rate. Soil temperature and soil water potential was monitored in all treatments. Onions were rated for many economic parameters, thrips, IYSV symptoms, and ELISA. <br /> The combined effects of variety, irrigation system, irrigation criterion, and nitrogen (N) rate on IYSV expression and onion yield and grade were evaluated in 2008. N fertilization at 224 kg/ha failed to improve disease incidence or yield over 112 kg/ha. Drier irrigation criteria (30 kPa) resulted in more severe IYSV symptoms and lower marketable, colossal, and colossal plus super-colossal bulb yield than the wetter irrigation criteria. There were no significant interactions between variety, irrigation criteria, and N rate either year. Some varieties demonstrated tolerance with clearly different performance in the presence of IYSV. Kaolin foliar treatments failed to suppress IYSV. Screening insecticides for those with efficacy against thrips and those which reduce the impact of IYSV were conducted. Formetanate hydrochloride and spirotetramat were two compounds that are not yet registered for use in onion that seem to be very effective in controlling thrips and reducing the incidence of iris yellow spot virus. They were particularly effective when applied in a rotation with other insecticides such as methomyl and spinetoram. <br /> <br /> Washington Hanu Pappu, Washington State University, Pullman, WA - Seasonal dynamics of thrips vectors: In cooperation with Silvia Rondon of Oregon State. Year 3 of a study to determine the seasonal dynamics of onion thrips as IYSV vectors: we have developed an ELISA test for detecting the virus in the insect using an antiserum that detects a viral protein that will be present in the thrips only if the virus had replicated. Presence of this protein is an indication that the particular adult is capable of transmitting the virus. Testing of the collected thrips by ELISA is ongoing. Biological characterization and genetic diversity of virus strains; in cooperation with Chris Cramer and Howard Schwartz. We are evaluating several field isolates of IYSV to define and determine biological properties in terms of severity/virulence using a set of indicator hosts such as datura and Nicotiana benthamiana. Preliminary findings suggest that there are severe and mild strains of the virus that differ in their virulence when inoculated on these hosts. Genetic diversity studies of the virus isolates from different parts of the US and the world are continuing. Results show that there are clades suggesting some influence of geographic delineation on the sequence diversity of these isolates. Genetic diversity studies would help us better understand the introductions, movement and evolution of the virus and virus populations. <br /> <br /> Objective 3. Transfer information on progress dealing with IYSV and thrips biology and IPM strategies to the onion industry and other interested parties <br /> <br /> New York Brian Nault, Cornell University, Geneva, NY - Several meetings were held in 2010 to inform NYs onion industry about results from this project: the Annual Winter New York Onion Industry Council Meeting in Ithaca in January, the Empire State Fruit and Vegetable EXPO in Syracuse in February, the Onion School in Middleburg in March, the Oswego Twilight Meeting in June, the Annual Summer New York Onion Industry Council Meeting in Pine Island in July and the Elba Muck Onion Meeting in Elba in August. Additionally, an annual workshop was held in Ithaca that included a session to update Cornell Cooperative Extension Educators about results from this project. Information pertaining to this subject was also presented at the National Allium Research Conference in Reno, NV in December and at the Annual Entomological Society of America Meeting in San Diego, CA also in December.<br /> <br /> Oregon - Lynn Jensen, Clint Shock, Erik Feibert, and Monty Saunders, Oregon State University, Ontario, OR - The project has continued to effectively transfer information pertinent to IYSV and thrips biology to growers, other onion industry parties, and the public through numerous meetings, field days, publications, and the internet. Results have been effectively communicated by grower and fieldman participation in the project planning and evaluation of results, field days for growers July 14, 2010 and August 29, 2010, grower meetings on February 2, 2010, internet web sites, and results being reported in Onion World. An extension brochure was written describing how to optimize onion irrigation scheduling, including how to minimize IYSV through irrigation management. The extension brochure was published in September, 2010. An early version of the extension brochure was published for worldwide distribution in Onion World.<br />

Publications

Beer S. V., Zaid, A. M., and Bonasera, J. M. 2011. Studies of bacterial problems of onion in New York  2010. Proceedings of the 2011 Empire State Fruit & Vegetable Expo. Pages 105-107.<br /> <br /> Carr, E. A., Bonasera, J. M., Zaid, A. M., Lorbeer, J. W., and Beer, S. V. 2010. First report of a bulb disease caused by Pantoea ananatis in New York. Plant Disease. 94(7): 916-916.<br /> <br /> Nault, B.A., and Shelton, A.M. 2010. Impact of insecticide efficacy on developing action thresholds for pest management: A case study of onion thrips (Thysanoptera: Thripidae) on onion. J. Econ. Entomol. 103(4): 1315-1326.<br /> <br /> Diaz-Montano, J., M. Fuchs, B. A. Nault and A. M. Shelton. 2010. Evaluation of onion cultivars for resistance to onion thrips (Thysanoptera: Thripidae) and Iris yellow spot virus. J. Econ. Entomol. 103(3): 925-937.<br /> <br /> Hsu, C., C. A. Hoepting, M. Fuchs, A. M. Shelton and B. A. Nault. 2010. Temporal dynamics of Iris yellow spot virus and its vector, Thrips tabaci (Thysanoptera: Thripidae), in seeded and transplanted onion fields. Environ. Entomol. 39(2): 266-277.<br /> <br /> Nault, B.A., and Hessney, M.L. 2010. Onion thrips control in onion, 2009. Arthropod Management Tests, 2009. 35: E13.<br /> <br /> Nault, B.A., and Shelton, A.M. 2010. Battling onion thrips using insecticides. Cornell Cooperative Extension, Cornell Vegetable Program. Veg Edge 6(6): 15-17.<br /> <br /> Nault, B.A. 2010. New insecticides for insect pest management. Cornell Cooperative Extension, Cornell Vegetable Program. Veg Edge 6(2): 14-15.<br /> <br /> Nault, B.A. 2010. Thrashing thrips. American Vegetable Grower. November 2010. pp. 43-44.<br /> <br /> Nault, B.A. 2010. Onion thrips control in New York. Onion World. 26(1): 12-14.<br /> <br /> Schwartz, H. F., Gent, D. H., Fichtner, S. M., Khosla, R., Reich, R., Camper, M. A., Mahaffey, L. A., and Cranshaw, W. S. 2010. Spatial and temporal distribution of Iris yellow spot virus and thrips in Colorado onion fields. APS Plant Management Network doi:10:1094/PHP-2010-0820-01-RS. <br /> <br /> Zaid, A. M., Bonasera, J. M. and Beer, S. V. 2010. Transposon mutagenesis of Pantoea ananatis: Isolation and characterization of a Tn5-induced mutant with reduced virulence to onion. Phytopathology 100:S144<br /> <br /> Other Activities <br /> <br /> 1. Research Reports: Abstracts and Papers at International Professional Meetings <br /> <br /> Bag, S., Cramer, C., Schwartz, H.F., and Pappu, H.R. 2010. Biological Characterization of Distinct Strains of Iris yellow spot virus. Poster presentation at the Australasian Plant Virology Workshop, Melbourne, Australia. Nov. 16-19, 2010.<br /> <br /> Szostek, S. A., and Schwartz, H. F. 2010. Iris Yellow Spot Virus of Onion. Fact Sheet, 4 pp. (The Global Specialist, in collaboration with Nunhems Seed Co.); printed in English & Spanish. Spanish translation provided by my former student, Dr. Rodolfo Velazquez, INIFAP-Zacatecas, Mexico.<br /> <br /> Velazquez, V.R., Mena, C. J., Reveles, H.M., Amador, R. M. D., and Schwartz, H. F. 2010. El Virus de la Mancha Amarilla del Iris: Una nueva amenaza para el ajo y la cebolla en Aguascalientes y Zacatecas. [Iris yellow spot virus: A new threat to garlic and onion in Aguascalientes and Zacatecas]. Tech. Bull. 21, Campo Exp. Zacatecas, CIRNOC-INIFAP, Mexico, 21 pages. <br /> <br /> 2. Research Reports: Abstracts and Papers at National Professional Meetings <br /> <br /> Boateng, C.O., Schwartz, H.F., and Otto, K. 2010. Evaluation of Onion Cultivars for Resistance to Iris yellow spot virus and Onion Thrips. Proc. 2010 National Allium Research Conference, Reno, Nevada, Dec. 9-10, 2010. Oral Paper. http://www.unce.unr.edu/adhoc/narc2010/agenda/<br /> <br /> Cramer, C.S. 2010. Evaluation of onion plant introduction accessions for leaf characteristics. 107th Annual Conference of the American Society for Horticulture Science. Palm Desert, Calif. Aug. 2-5, 2010.<br /> <br /> Cramer, C.S. 2010. Progress toward developing onion cultivars tolerant to Iris yellow spot virus. 107th Annual Conference of the American Society for Horticulture Science. Palm Desert, Calif. Aug. 2-5, 2010.<br /> <br /> Cramer, C.S. 2010. Screening of onion plant introduction accessions for Iris yellow spot disease severity. 107th Annual Conference of the American Society for Horticulture Science. Palm Desert, Calif. Aug. 2-5, 2010.<br /> <br /> Cramer, C.S. 2010. Variation in onion thrips number per plant among onion plant introduction accessions. 107th Annual Conference of the American Society for Horticulture Science. Palm Desert, Calif. Aug. 2-5, 2010.<br /> <br /> Cramer, C.S. 2010. Screening of onion plant introduction accessions for Iris yellow spot disease severity. 4th Annual Plant Breeding Workshop. Annual Meetings of the Plant Breeding Coordinating Committee and National Association of Plant Breeders. Johnston, IA. Aug. 15-17, 2010.<br /> <br /> Cramer, C.S. 2010. Screening of onion plant introduction accessions for Iris yellow spot disease severity. 2010 University Research Council Research and Creative Arts Fair. Las Cruces, NM. Oct. 1, 2010.<br /> <br /> Cramer, C.S. Screening winter-sown onion entries for Iris yellow spot virus resistance. W1008: Biology and management of Iris yellow spot virus (IYSV) and thrips in onions. Regional research project annual meeting. Reno, NV. Dec. 8, 2010.<br /> <br /> Cramer, C.S. 2010. Evaluation of onion plant introduction accessions for leaf characteristics. 2010 National Allium Research Conference. Reno, NV. December 8-10, 2010. <br /> <br /> Cramer, C.S. 2010. Screening of onion plant introduction accessions for Iris yellow spot disease severity. 2010 National Allium Research Conference. Reno, NV. December 8-10, 2010.<br /> <br /> Cramer, C.S. 2010. Variation in onion thrips number per plant among onion plant introduction accessions. 2010 National Allium Research Conference. Reno, NV. December 8-10, 2010.<br /> <br /> Diaz-Montano, J., A. M. Shelton, B. Nault and J. Fail. 2010. Onion leaf color effects on attraction to onion thrips (Thrips tabaci Lindeman). Entomological Society of America Annual Meeting, San Diego, CA.<br /> <br /> Hsu, C. L., and B. A. Nault. 2010. Spatial distribution of onion thrips (Thrips tabaci) in western New York onion fields. Entomological Society of America Annual Meeting, San Diego, CA.<br /> <br /> Hsu, C. L., B. A. Nault and C. A. Hoepting. 2010. Relationships between nitrogen fertilizer levels, onion thrips (Thrips tabaci) populations and fresh market bulb yields in New York. National Allium Research Conference. December 9-10, 2010. Reno, NV.<br /> <br /> Hsu, C. L., C. A. Hoepting, S. Reiners and B. A. Nault. 2010. Impact of nitrogen on onion thrips populations and implications for management, pp. 114-120. . In: Proceedings of the 2010 Empire State Fruit and Vegetable Expo. January 25-27, 2010. Syracuse, NY. Cornell Coop. Ext. and New York State Vegetable Growers Association.<br /> <br /> Nault, B. A. 2010. Can biopesticides be effective for managing onion thrips in onion? Biopesticide Industry Alliance Semi-Annual Meeting. Ottawa, ON, Canada.<br /> <br /> Nault, B. 2010. Developing an insecticide use strategy for thrips management in onion. Entomological Society of America Annual Meeting, San Diego, CA.<br /> <br /> Nault, B. A., C. L. Hsu and C. Hoepting. 2010. Managing onion thrips with insecticides  Overcoming a multitude of challenges. In: Proceedings of the 2010 National Allium Research Conference. December 9-10, 2010. Reno, NV.<br /> <br /> Nault, B. A., C. L. Hsu, E. A. Smith, M. L. Hessney, M. Fuchs and A. M. Shelton. 2010. Managing onion thrips and status of Iris yellow spot virus in New York, pp. 113-117. In: Proceedings of the 2010 Empire State Fruit and Vegetable Expo. January 25-27, 2010. Syracuse, NY. Cornell Coop. Ext. and New York State Vegetable Growers Association.<br /> <br /> Nault, B., C. Hsu and C. Hoepting. 2010. Update on onion thrips and Iris yellow spot virus research in New York. Annual Meeting for Multi-State Project W1008: Biology and Management of Iris yellow spot virus (IYSV) and Thrips in Onions. Reno, NV.<br /> <br /> Nault, B. A., C. L. Hsu and C. Hoepting. 2010. Managing onion thrips with insecticides  Overcoming a multitude of challenges. National Allium Research Conference. December 9-10, 2010. Reno, NV.<br /> <br /> Nault, B. A., C. Hsu, E. Smith, A. Shelton, M. Fuchs and C. Hoepting. 2010. Epidemiology of Iris yellow spot virus in eastern North American onion ecosystems. Eleventh International Plant Virus Epidemiology Symposium, Ithaca, NY. June 20-24, 2010. <br /> <br /> Shock, C.C., E.B.G. Feibert, L.D. Saunders, L.B. Jensen. 2010. Oregon 2009 progress on the biology and management of Iris Yellow Spot Virus (IYSV) and thrips in onions. Written report 12 January 2010 to W1008, the national IYSV working group.<br /> <br /> Shock, C. C., E.B.G. Feibert, L.D. Saunders, L.B. Jenson, K. Mohan, R.S. Sampangi, and H. Pappu. 2010. 2009 onion variety trials. Oregon State University Agri Exp Station, 2009 Annual rpt: 27-37. http://www.cropinfo.net/AnnualReports/2009/OnionVarietyTrials2009.html<br /> <br /> Shock, C.C., E.B.G. Feibert, and L.D. Saunders. 2010. Performance of onion varieties in a field with high iris yellow spot virus presence. Oregon State Univ Agr Exp Station, 2009 Annual report: 38-40. ttp://www.cropinfo.net/AnnualReports/2009/OnionVarietyPerformanceIYS2009.html<br /> <br /> Shock, C. C., E.B.G. Feibert, L.D. Saunders, L.B. Jenson, K. Mohan, R.S. Sampangi, and H. Pappu. 2010. Management of onion cultural practices to control the expression of Iris Yellow Spot Virus. Oregon State University Agri Exp Station, 2009 Annual Report: 47-65. http://www.cropinfo.net/AnnualReports/2009/OnionManagementIrisYellowSpotVirus2009.html<br /> <br /> Shock, C.C., E.B.G. Feibert, and J. Taberna. 2010. Effect of harvest timing on onion yield and storability. Oregon State University Agricultural Experiment Station, 2009 Annual Report: 81-91. http://www.cropinfo.net/AnnualReports/2009/OnionHarvestTimeEffects.html<br /> <br /> Smith, E., A. DiTomasso, M. Fuchs, A. Shelton and B. Nault. 2010. Weed hosts of onion thrips (Thrips tabaci) and implications for Iris yellow spot virus epidemiology in onion. National Allium Research Conference. December 9-10, 2010. Reno, NV.<br /> <br /> Szostek, S.A., and Schwartz, H.F. 2010. Generating Clean Thrips Colonies and Quantifying IYSV at Onion Leaf Locations. Proc. 2010 National Allium Research Conference, Reno, Nevada, Dec. 9-10, 2010. Oral Presentation. http://www.unce.unr.edu/adhoc/narc2010/agenda/<br /> <br /> 3. Reports at Grower meetings and field days<br /> <br /> Cramer, C.S. Screening winter-sown onion entries for Iris yellow spot virus resistance. New Mexico Dry Onion Commission meeting. Las Cruces, NM. March 24, 2010.<br /> <br /> Cramer, C.S. Screening onion entries for tolerance/resistance to Iris yellow spot virus. NM Onion Field Day. Las Cruces, NM. July 21, 2010.<br /> <br /> Hsu, C., and Nault, B. A. 2010. Demonstration of the interaction between nitrogen and onion thrips. Elba Muck Onion Twilight Meeting. Elba, NY. Cornell Cooperative Extension Vegetable Program. <br /> <br /> Hsu, C. L., C. A. Hoepting, S. Reiners and B. A. Nault. 2010. Impact of nitrogen on onion thrips populations and implications for management. Empire State Fruit and Vegetable Expo. Syracuse, NY. <br /> <br /> Nault, B. A. 2010. Onion insect management. Cornell Cooperative Extension Agriculture and Food Systems November In-Service, Ithaca, NY. November 16, 2010.<br /> <br /> Nault, B. A. and C. A. Hoepting. 2010. Onion thrips management in onion using Agri-Mek. 2010  Disease and insect update meeting sponsored by Syngenta Crop Protection. Dundee, NY.<br /> <br /> Nault, B. A. 2010. Tank mix interactions among insecticides, fungicides and adjuvants for control of onion thrips. Elba Muck Onion Twilight Meeting. Elba, NY. Cornell Cooperative Extension Vegetable Program. <br /> <br /> Nault, B. A., C. L. Hsu, A. Shelton and M. L. Hessney. 2010. Onion insect management update. New York State Onion Industry Council Summer Tour and Meeting, Pine Island, NY. Cornell Cooperative Extension. <br /> <br /> Nault, B. A. 2010. Update on onion thrips management and IYSV. Onion School. Middletown, NY. Cornell Cooperative Extension. <br /> <br /> Nault, B. A., C. L. Hsu, E. A. Smith, M. L. Hessney, M. Fuchs and A. M. Shelton. 2010. Managing onion thrips and status of Iris yellow spot virus in New York. Empire State Fruit and Vegetable Expo. Syracuse, NY<br /> <br /> Nault, B. A., C. Hsu, A. Shelton, M. Fuchs, A. Taylor, J. Diaz-Montano, E. Smith, S. Reiners, and C. Hoepting. 2010. Onion insect management and Iris yellow spot virus research highlights from 2010. New York Onion Industry Council Winter Meeting, Ithaca, NY. <br /> <br /> Schwartz, H. F. 2010 Onion virus management and updates. Annual Education Meeting of the Colorado Onion Association on January 28, 2010 at Eaton, CO.<br /> <br /> Schwartz, H. F. 2010. Onion virus management and updates. Annual Field Day of the Colorado Onion Association on September 9, 2010 at Brighton, CO.<br /> <br /> Shock, C.C. E.B.G. Feibert, L.D. Saunders, L.B. Jensen, S.K. Mohan, R.S. Sampangi, and H. Pappu. 2010. Iris Yellow Spot Virus control through stress reduction. 49th Annual Meeting of the Malheur Onion Growers Association and Idaho Onion Growers Association, 2 February 2010, Ontario, OR. <br /> <br /> Shock, C.C., E.B.G. Feibert*, L.D. Saunders, L.B. Jensen, K.S. Mohan, R. Sampangi, and H. Pappu. 2010. Comparison of irrigation systems and irrigation criteria for onion production under IYSV pressure. Summer Farm Festival and Annual Field Day, OSU Malheur Experiment Station. 13 July 2010. Ontario, OR.<br /> <br /> Shock, C.C. E.B.G. Feibert, L.D. Saunders, L.B. Jensen, S.K. Mohan, R.S. Sampangi, and H. Pappu. 2010. Onion variety trial report 2009. 49th Annual Meeting of the Malheur Onion Growers Association and Idaho Onion Growers Association, 2 February 2010, Ontario, OR. <br /> <br /> Shock, C.C. and E.B.G. Feibert. 2009. Onion Drip Irrigation, Pacific Northwest Vegetable Association, Kennewick, WA. November 11, 2009.<br /> <br /> Internet Resources<br /> <br /> Schwartz, H. F. 2010. Web site dedicated to information and resources on onion pest management and/or thrips and IYSV. http://www.alliumnet.com/index.htm<br /> <br /> Schwartz, H. F. 2010. Onion Disease Management strategies, reports and publications, including those on IYSV and thrips. http://www.colostate.edu/Orgs/VegNet/vegnet/onions.html<br /> <br /> Update on onion thrips management: http://www.growingproduce.com/gptv/?vid=216<br /> <br /> Other Related Activities<br /> <br /> 2010 - Submitted a package to the New York State Department of Environmental Conservation for their consideration of a Specific Emergency Exemption (FIFRA Section 18) for the use of spirotetramat (Movento) on onion for onion thrips control for the 2010 season. The Crisis Exemption request was granted by NYSDEC from June- September 2010.<br /> <br /> 2010 - Submitted a package to the New York State Department of Environmental Conservation for their consideration of a Specific Emergency Exemption (FIFRA Section 18) for the use of abamectin (Agri-Mek 0.15EC) on onion for onion thrips control for the 2010 season. The Crisis Exemption request was granted by NYSDEC from June- September 2010. <br />

Impact Statements

1. Germplasm was identified that possessed foliage characteristics that are associated with onion thrips feeding nonpreference. In addition, germplasm was identified that possessed a reduced number of thrips per plant than most entries. Both of these characteristics suggest that there is the genetic potential for reduced thrips feeding and possibly reduced Iris yellow spot virus spread.
2. Outputs of this work posted on web sites and presented at various meetings will be used by the Colorado and national onion industries, growers, seed company breeders and pathologists, and integrated pest management specialists to select more effective management strategies including the promotion of varieties that are less susceptible to damage by thrips and the virus.
3. More growers are adopting onion varieties with greater tolerance to IYSV. Seed availability is still a limiting factor for these new varieties.
4. Due to better knowledge of the transmission of IYSV, fewer growers are planting over-wintering onions. With fewer overwintering onions and better cull onion disposal, growers are breaking the natural green bridge keeping IYSV pressure high from one production year to the next. Some growers continued to suffer IYSV related yield losses due to over-wintering onion bulb or seed fields close to their summer production fields.
5. More growers are using soft insecticides to control trips early in the season allowing natural predators to help control thrips, at least at the beginning of the summer. These insecticide use strategies have recently been proven to be effective in replicated field tests.
6. 3. Research at Cornell University has identified new and selective insecticides and strategies to apply them enabling growers to keep onion thrips populations under control during the 2009 growing season. By following Cornell recommendations, it was possible for onion growers to decrease the frequency of sprays and reduce the number of insecticide sprays applied per season.

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Report Information

Participants

Clint Shock Oregon State University clinton.shock@oregonstate.edu;Tim Waters Washington State University twaters@wsu.edu;Brian Nault Cornell University ban6@cornell.edu;Robert T. Sakata Sakata Farms, Inc. rtsakata@aol.com;Stephanie Walker New Mexico State University swalker@nmsu.edu;Mark Uchanski New Mexico State University uchanski@nmsu.edu;Shannon Pike Enza Zaden Research USA, Inc. shannon.pike@enzausa.com;Stuart Reitz USDA-ARS stuart.reitz@ars.usda.gov;
Howard Schwartz Colorado State University howard.schwartz@colostate.edu;
Chris Cramer New Mexico State University cscramer@nmsu.edu;
Thaddeus Gourd Colorado State University tgourd@adcogov.org;Joel Canestrino Hazera Inc. jcanestrino@hazerainc.com;Cynthia Hsu Cornell University clh33@cornell.edu;Juan Carlos Brevis Enza Zaden Research USA, Inc. juan.brevis@enzausa.com;Dave Whitwood Crookham Company davew@crookham.com;Ron Gitaitis University of Georgia dronion@uga.edu;
Babu Srinivasan University of Georgia babusri@uga.edu;Neel Kamal New Mexico State University nkamal@nmsu.edu;Narinder Singh New Mexico State University narinder@nmsu.edu;Ray Muhyi New Mexico State University rmuhyi@nmsu.edu;Lee Sommers Colorado State University Lee.sommers@colostate.edu;Steve Beer Cornell University svb1@cornell.edu;Christy Hoepting Cornell University cah59@cornell.edu

Brief Summary of Minutes

Accomplishments

Objective 1. Screen onion germplasm for improved levels of tolerance to Iris yellow spot virus (IYSV) and thrips <br /> <br /> Colorado (H. F. Schwartz, W. Cranshaw, M. Bartolo, T. Gourd, B. Hammon) - During 2011, the Colorado team identified the following germplasm with significantly greater plant vigor after season-long exposure to thrips and the virus: selections from Plant Introduction (PI) lines 258956 (Calderana), 288909, 343049, 546188 (Winegar), DP Seeds Mesquite, Crookham 05-05, and B5336C (Mike Havey selection from P53-364-2C). These lines were selected as candidates for the translational genomics study coordinated by colleagues involved with the USDA-SCRI Project 2008-04804. The evaluation design verified that screening nurseries planted in fields with a history of problems from onion thrips and IYSV could provide moderate to severe pest and disease pressure to enable the identification of less susceptible onion entries (varieties, breeding lines or germplasm).<br /> <br /> Idaho (S.K. Mohan and R.S. Sampangi) - In collaboration with C. Shock, 50 commercial onion cultivars were screened for resistance to IYSV. All the varieties were susceptible under field conditions to varying degrees, none showing total resistance.<br /> <br /> New Mexico (C. Cramer) - Eighty-eight onion breeding lines selected for IYSV tolerance, 25 plant introduction (PI) accessions from the U.S. germplasm collection, 11 experimental breeding lines from the New Mexico State University (NMSU) breeding program, 10 commercial cultivars, and 12 experimental commercial breeding lines were evaluated for the number of thrips per plant, leaf color, leaf waxiness, IYSV disease symptoms, and bulb yield. For those entries tested as transplants, adult and juvenile onion thrips number per plant was highest at 9 weeks post transplanting while the number decreased afterwards up to 15 weeks. Among those breeding lines selected for IYSV tolerance, plants of NMSU 10-592-1, NMSU 10-594-1, NMSU 10-596-1, NMSU 10-597-1, NMSU 10-634-1, NMSU 10-737, and NMSU 10-778 averaged less than 25 thrips at 9 weeks that was less than the susceptible check, Rumba. In addition to these selected lines, 22 additional selected lines and 19 PI accessions had fewer thrips per plant than Rumba at 9 weeks. Plants of PIs 344392 and 289689 had less than 25 thrips at 9 weeks. At 12 weeks post transplanting, plants of 46 selected lines and 17 PI accessions had fewer thrips than plants of Rumba. Plants of 11 selected lines (NMSU 10-589-1, 10-592-1, 10-593-1, 10-594-1, 10-597-1, 10-618-1, 10-619-1, 10-702, 10-712, 10-737, 10-767), PI 289689, and PI 391509 averaged less than 13 thrips per plant. At 15 weeks post transplanting, plants of 35 selected lines and 8 PI accessions averaged fewer thrips than plants of Rumba. Of these entries, plants of 19 selected lines (NMSU 10-580-1, 10-589-1, 10-593-1, 10-594-1, 10-597-1, 10-615-1, 10-618-1, 10-619-1, 10-696-1, 10-697-1, 10-702, 10-710, 10-711, 10-732, 10-734, 10-737, 10-767, 10-778, 10-817), PI 179627, PI 183660, and PI 289689 averaged less than 9 thrips per plant.<br /> <br /> <br /> For those entries sown directly in the field, numbers of thrips per plant remained unchanged from 13 to 21 weeks post sowing. At 13 weeks, plants of 20 selected lines, 1 NMSU experimental line, 1 commercial cultivar, and 4 experimental commercial breeding lines averaged fewer thrips per plant than plants of Rumba. Of those entries, plants of NMSU 10-795, NMSU 10-800, and NMSU 10-814 averaged less than 6 thrips per plant. At 17 weeks post sowing, no entry averaged fewer thrips per plant than Rumba. At 21 weeks post sowing, only 5 experimental commercial breeding lines averaged fewer thrips per plant than plants of Rumba. <br /> <br /> <br /> Of those entries tested, plants of 71 selected lines, 5 PI accessions, 11 NMSU experimental lines, 3 commercial cultivars, and 12 experimental commercial breeding lines were rated as having light to dark green leaf color. With regards to leaf waxiness, plants of 36 selected lines, 4 PI accessions, 5 NMSU experimental lines, 2 commercial cultivars, and 4 experimental commercial breeding lines were rated as having semi-glossy to glossy leaves. Plants of NMSU 07-54-1, NMSU 10-592-1, NMSU 10-593-1, NMSU 10-594-1, NMSU 10-597-1, NMSU 10-613-1, NMSU 10-618-1, NMSU 10-619-1, NMSU 10-737, NMSU 10-778, NMSU 10-814, and NMSU 10-816 possessed glossy foliage that was light green in color. <br /> <br /> <br /> For those entries tested as transplants, plants of NMSU 10-597-1, NMSU 10-796, and NMSU 10-817 exhibited a lower IYS disease severity at 12 weeks post transplanting than plants of Rumba. At the same time, NMSU 10-597-1 and NMSU 10-796 exhibited a lower disease incidence than Rumba. At 14 weeks post transplanting, plants of 13 selected lines and 7 PI accessions exhibited a lower disease severity than plants of Rumba. NMSU 10-589-1, NMSU 10-718, and PI 391509 exhibited a lower disease incidence at 14 weeks than Rumba. At 16 weeks, no selected lines or PI accessions exhibited a lower disease severity than Rumba. By 16 weeks, disease incidence had reached 100% for all entries. At 18 weeks, plants of 19 selected lines and 6 PI accessions exhibited a lower IYS disease severity than plants of Rumba. <br /> <br /> <br /> For those entries sown directly in the field, plants of 23 selected lines, 5 NMSU experimental lines, and 4 experimental commercial breeding lines exhibited a lower IYS disease severity at 21 weeks than plants of Rumba. At the same time, NMSU 10-782, NMSU 10-799, NMSU 10-800, NMSU 10-807, NMSU 10-813, NMSU 10-814, NMSU 10-833, NMSU 07-54-1, and E204IYSV2011 exhibited a lower disease incidence than Rumba. At 23 weeks post seeding, plants of 17 selected lines, 2 NMSU experimental lines, 2 commercial cultivars, and 2 experimental commercial breeding lines exhibited a lower disease severity than plants of Rumba. NMSU 07-54-1, NMSU 07-55-1, NMSU 10-776, NMSU 10-782, NMSU 10-799, NMSU 10-813, NMSU 10-814, NMSU 10-816, and NMSU 10-833 exhibited a lower disease incidence than Rumba. <br /> <br /> <br /> For those entries tested as transplants, NMSU 07-30-2, NMSU 07-35-1, NMSU 10-768, NMSU 10-778, and PI 546201 exhibited a colossal market class bulb yield that was greater than the yield of other entries. NMSU 07-30-2, NMSU 07-35-1, NMSU 10-634-1, NMSU 10-768, NMSU 10-778, NMSU 10-784, NMSU 10-817, and PI 546192 exhibited a jumbo bulb yield that was greater than the yield of other entries. For those entries sown directly in the field, NMSU 07-30-2 and E208IYSV2011 exhibited a jumbo bulb yield that was greater than the yield of other entries. Individual plants, that exhibited few IYSV symptoms, were selected at bulb maturity from 43 different selected lines, 11 NMSU experimental breeding lines, 3 commercial cultivars, and 2 PI accessions for a total of 520 bulbs. These bulbs are being pollinated in the hopes of finding progeny that possess a higher level of IYSV tolerance.<br /> <br /> <br /> Utah (D. Drost) - As part of yearly conducted variety trials, 31 commercially available Spanish onion cultivars were assessed for productivity, maturity and rated for IYSV. While symptoms expressed in 2011 were low, all the varieties were susceptible to IYSV under field conditions and all had visual virus symptoms to some degree.<br /> <br /> <br /> Objective 2. Study the biology and epidemiology of IYSV and thrips, and impacts of chemical, cultural and biological tactics that can reduce their impacts upon onions. <br /> <br /> Colorado (H. F. Schwartz, W. Cranshaw, M. Bartolo, T. Gourd, B. Hammon) - During 2011, volunteer onions were monitored after leaf and bulb expansion for the presence of thrips and IYSV in the vector and plants. Thrips numbers increased from 1 to nearly 100 per plant over a 5-week period; with IYSV incidence at 30% (of 16 thrips/plant) early, reaching 100% (of 98 thrips/plant) 4 weeks later. Volunteer onion plant incidence varied from 20% with IYSV in the early season to 100% 4 weeks later. This high incidence of IYSV in thrips and volunteer onions coincided with bulb initiation in transplanted onion and mid vegetative growth in seeded onion crops planted nearby.<br /> <br /> <br /> During 2010, scapes, umbels and seed from individual plants (of Pentium, Solid Gold and Red Defender) exhibiting typical symptoms of IYSV with confirmation by ELISA were harvested. Seed number was correlated with size of the umbel, and seed weight was correlated with number of seeds. IYSV has not been detected in 3-4 week old plants grown from seed harvested from infected plants; however, germinated seed from a few umbels have tested positive for IYSV by ELISA. Additional testing is underway with seed and umbel samples from 2010 and 2011, and results need to be confirmed by PCR.<br /> <br /> <br /> In the arid West, onions are often grown with companion crops such as barley (living mulch) to protect seedling onionss from wind injury. Both farmers and researchers have observed lower thrips injury in onion/companion crop fields in the past. In an effort to find out why, an onion companion crop insect and arachnid population dynamics field study was initiated in the spring of 2011. The objectives were to determine which thrips predators and parasites are found inhabiting the barley companion crop; determine what other insects/arachnids dwell in this living mulch; determine if there is a relationship of predator/parasite and thrips populations; and determine if living mulch reduce thrips injury and IYSV. Four field locations in Colorado were sampled once during mid-June using a Stihl gas powered BG56 Shredder and Vacuum with a no thrips insect screen. The sampled area was 10 row feet (25 square feet), with four samples taken at each field location. Eight beneficial predator and parasite families were identified from the field samples. The average of all populations of insects and arachnids at all locations revealed that ladybird beetle larvae were the most numerous found followed by spiders, braconid wasps, syrphid flies, big eyed bugs, ladybird beetle adults, nabids, lacewings and predacious mites. Six plant feeding insect families and one phytophagous mite family were found in the field samples. The average of all populations of insects and arachnids at all locations revealed that phytophagous mites were the most numerous followed by aphids, thrips, leafhoppers, leaf beetles, flies, one grasshopper and one box elder bug adult. Generally, fewer thrips were found on onion plants when at least 0.3 ladybird larvae were found per square foot of vegetation. Later in the season, an evaluation of thrips populations from the four field locations ranged from 1 to 15.4 thrips per plant in companion crop planted fields. In one non companion crop planted field located next to one test location, 20.5 thrips were found per onion plant compared with 9.2 thrips per plant in the onion companion crop field. Little to no IYSV was found at any field locations.<br /> <br /> <br /> Florida (S. Reitz) - Laboratory studies were conducted to determine the repellency of kaolin to thrips and the effect of kaolin on the amount of thrips feeding. No choice trials were conducted by exposing adult female thrips to either kaolin treated foliage or control foliage. Leaves were treated with a 6.25% aqueous mixture of kaolin (Surround WP) and Tween 80 (1%) as a spreader/sticker, or a control solution of water plus Tween. The amount of kaolin coverage was determined by measuring white areas of the leaf surface through the use of digital analysis software (Sigmascan Pro). Repellency and feeding were evaluated at two time intervals following treatment. Treated foliage was allowed to dry for 1 hour or 24 hours after treatment. Leaf sections were placed in arenas (3.5 cm diameter) lined with agar, and individual female thrips were introduced into arenas for 24 hours. At the end of the 24 hour trials, the location of each thrips was recorded. Foliage was rinsed with tap water, and the amount of feeding damage measured through the use of digital analysis software. Data were analyzed with generalized linear models. Kaolin treatments resulted in significantly more thrips being located off of the leaf surface for both time intervals. Sixty-three percent of thrips exposed to kaolin treated foliage were found off of the foliage at the end of the test, compared with 46% of the thrips exposed to control foliage. <br /> <br /> <br /> Georgia (R. Gitaitis, R. Srinivasan) - Lisianthus (Eustoma russellianum) was used as an indicator host and a platform for transmission studies of IYSV to study mechanical transmission. Mechanical inoculation tests from IYSV-infected onion plants to non-infected lisianthus plants resulted in a mean transmission rate of 82.5%, and from IYSV-infected lisianthus plants to non-infected lisianthus plants resulted in a mean transmission rate of 89.2%. T. tabaci adults transmitted IYSV at a rate of 80% from infected onion plants to non-infected lisianthus plants. To assess IYSV distribution in infected lisianthus plants, leaf sections, stems, and roots were tested by enzyme-linked immunosorbent assay (ELISA). All the plant parts tested positive for IYSV, but not on every plant assayed. More severe symptoms developed on inoculated plants incubated at 18 and 23°C or 25 and 30°C temperature regimes than at the 30 and 37°C regime. Symptoms were observed earliest on plants incubated at the 25 and 30°C. Besides improving our understanding of virusvector interactions, lisianthus can be useful to monitor disease incidence from an epidemiological standpoint. Lisianthus could be used as a sentinel plant in agricultural settings to monitor the initial incidence of IYSV and assess inoculum pressure. Monitoring of results could prompt appropriate management measures such as insecticide applications.<br /> <br /> <br /> Onion bulb culls imported from Peru are the source of IYSV in Georgia. These culls also harbored live onion thrips (Thrips tabaci), also most likely from Peru since they were found inside bulbs in the packinghouse. Later a potential shift in the makeup of thrips populations from tobacco thrips (Frankliniella fusca) to onion thrips in Georgia fields led to a hypothesis that a more aggressive T. tabaci biotype was introduced from Peru. Thus, a survey was conducted to identify the origin of T. tabaci populations collected from onions in Georgia. Origin of thrips was based on polymorphisms in mitochondrial cytochrome oxidase 1 (CO1) and ribosomal ITS2 sequences. Parsimony and Bayesian analysis of CO1 sequences indicated all Peruvian thrips fell in to a single clade that contained only one sample from Georgia. All the other Georgia taxa clustered in a different clade. It was concluded that CO1 sequences had potential use to identify geographical origin for intraspecies variation of thrips. On the other hand, ITS2 sequences indicated Peruvian and Georgia taxa were found in numerous clades with no discernible pattern to indicate geographic origin. Therefore, ITS2 sequences were not useful to assess intraspecies variation among thrips. Also, the data did not support theory that an introduced, more aggressive biotype accounted for the temporary shift from tobacco thrips to onion thrips in Georgia onion fields.<br /> <br /> <br /> Tobacco thrips is the major thrips pest of onion in Georgia. Hence, experiments were conducted to test the vector status of F. fusca in comparison with T. tabaci. The detection rates for F. fusca larvae and adults reared on IYSV-infected hosts were 4.5 and 5.1%, respectively, and for T. tabaci larvae and adults detection rates were 20 and 24%, respectively, indicating that both F. fusca and T. tabaci can transmit IYSV. Further, transmission efficiencies of F. fusca and T. tabaci were evaluated by using an indicator host, lisianthus. Both F. fusca and T. tabaci transmitted IYSV at 18 and 77%, respectively. Results confirmed that F. fusca also can transmit IYSV but at a lower efficiency than T. tabaci. Transmission data with Tomato spotted wilt virus (TSWV), another tospovirus, and F. fusca, resulted in 90% efficiency demonstrating the F. fusca population used in the onion experiment was a competent vector. These results suggest the transmission efficiency of a competent thrips vector can vary widely between two closely related viruses.<br /> <br /> <br /> Iris yellow spot virus (IYSV) continues to be detected annually since its introduction into Georgia from Peru in 2003. During a weed survey near an onion cull pile with a history of IYSV, spiny sowthistle (Sonchus asper) was identified as an asymptomatic host. Spiny sowthistle is widespread in Georgia, thereby presenting an opportunity to survey the spread of IYSV both within and outside onion-growing areas of the state. A total of 2011 sowthistle samples were tested using ELISA in this 3-yr study. Selected ELISA positive samples were confirmed with RT-PCR, and sample sequences were compared with known IYSV isolates deposited in GenBank. All IYSV sequences obtained from spiny sowthistles, regardless of county of origin, were most closely related to IYSV sequences from samples previously collected from onion in either Georgia or Peru. By the third year of the survey, IYSV-infected sowthistles were found in 79% of the counties in the onion-growing region and in 61% of the counties along transects running to the north, northwest and west of the onion-growing region. No positive samples were found in counties to the east of the onion-growing region. Since sowthistles are considered an annual plant and do not occur in the summer in Georgia, spiny sowthistles were initially dismissed as a possible green bridge for the virus between winter-grown onion crops. However, during the course of this survey a few spiny sowthistles were observed to act as a perennial in the mild, southern Georgia climate. At least one of those samples was positive for IYSV in two consecutive years. The presence of IYSV was also confirmed in spiny sowthistle roots, thus allowing for the possibility of IYSV over-summering between onion crops. Furthermore, spiny sowthistles supported T. tabaci survival and reproduction. Thrips-mediated transmission assays also confirmed that T. tabaci can efficiently transmit IYSV from onion plants to sowthistles. These findings demonstrate that IYSV has infected at least one weed widely throughout Georgia and has the potential for long distance spread, particularly in a northern and western direction.<br /> <br /> <br /> Idaho (S.K. Mohan and R.S. Sampangi) - More than 100 weed plants (leaves and roots) were sampled during the main cropping season (May-Sept) and fall (Oct-Dec) and tested for their possible role in serving as alternate hosts for both virus and vector (T. tabaci) in collaboration with H. Pappu. The samples were analyzed using two commercial ELISA kits (AGDIA, USA and DSMZ, Germany) for IYSV testing. Preliminary results showed varying absorbance values between the two kits employed and also among the weed species tested. A few weed species showed elevated values suggesting the presence of IYSV. Further testing by PCR is envisaged for determining the degree of reliability of the two ELISA test kits. <br /> <br /> <br /> New York (B. Nault, C. Hoepting, C. Hsu and S. Beer)  The performance of foliar-applied insecticides against onion thrips was examined in several studies. The best products included cyantraniliprole (HGW86 10OD), spinetoram (Radiant SC), spirotetramat (Movento) and abamectin (Agri-Mek 0.15EC). Section 18s for Movento and Agri-Mek were granted by EPA in 2010 in New York. The performance of new insecticides when tank mixed with fungicides containing spreader stickers was also investigated. Movento and Agri-Mek did not consistently work as well when tank mixed with fungicides that contained spreader stickers. The concern is that the spreader stickers in the fungicide formulation is interfering the penetrant used to assist getting the insecticide into the plant tissue. There is also concern that the penetrant may allow the fungicide to enter plant tissues to cause phytotoxicity. Research is needed in 2010 to resolve this issue. Action thresholds for new insecticides were examined. Although Movento and Agri-Mek controlled the thrips population when applied following a 3 thrips larvae per leaf threshold, these results may not be applicable in a bad thrips year. The thrips infestation was low for half the season due to cold and wet weather. Thus, until more research is conducted, growers should consider using a more conservative threshold such as 1 thrips larva leaf. This more conservative approach will be even more important if these products are tank mixed with fungicides and spreader stickers.<br /> <br /> <br /> The impact of nitrogen on onion thrips populations also was evaluated in 2011. The season total numbers of thrips and marketable bulb yield in plots applied with N rates at 75 and 150 lbs per acre were compared. The result was a 20 to 40% reduction in thrips densities over the season in plots that had 75 lbs per acre compared with 150 lbs per acre. More thrips were found on plants in the high N treatment, indicating that either more eggs were laid on these plants, more larvae survived on these plants, or both. There were no significant differences in marketable yield between the two treatments.<br /> <br /> <br /> Associations between bacteria that are pathogenic to onion and onion thrips, which may vector bacterial pathogens, were examined in 2011. The first step was to identify the suite of bacterial species causing decay in onion in New York. Known pathogens of onions were identified from symptomatic tissues in cull onions including Burkholderia cepacia, Pantoea ananatis, P. agglomerans and Enterobacter cloacae. In addition, Rahnella species, which have not been reported as pathogens of onion, were isolated from about 40% of the culls. E. cloacae, the pathogen that causes Enterobacter bulb decay in storage, as reported from California, Colorado and Washington, was isolated and characterized for the first time from onions grown and stored in New York. In addition, the presence of the pathogen was documented in symptomatic mid-season growing onions. Apparently the pathogen that results in unmarketable stored onions begins to develop in the field. In preliminary tests, several strains of Rahnella spp. that had been inoculated into putatively healthy bulbs, caused decay. These results suggest that this genus warrants a more intensive assessment of its pathogenic potential to onions. Additional work was done to learn more about the epidemiology of these bacterial pathogens.<br /> <br /> <br /> In limited analyzes of thrips collected from onion foliage rather late in the growing season, we identified strains of P. ananatis, P. agglomerans, B. cepacia and E. cloacae that were present both on the surface of the thrips and internally. However, further analyses are indicated before reaching a definite conclusion in regard to the possible presence of the several bacteria early in the season and the possible role of onion thrips in vectoring bacteria that cause decay in onion. <br /> <br /> <br /> Utah (D. Alston, D. Drost and C. Nischwitz)  Field crops and weeds growing in proximity to onion fields and onion plants and onion thrips were sampled during main cropping season (May-Sept) and tested for their role as alternate hosts or the presence of IYSV. Samples were analyzed using ELISA kits. By identifying plants in the farmscape surrounding onion fields that serve as virus reservoirs and onion thrips reproductive hosts, these plants could be targeted and treated or removed thus reducing the amount and source of IYSV inoculum near onion fields. Preliminary results showed varying absorbance values among crops, weeds and thrips tested. Weed species tested had variable absorbance values suggesting the presence of IYSV. Testing is on-going as significant numbers of samples were collected. <br /> <br /> <br /> Washington (L. du Toit, H. Pappu, B. Schroeder and T. Waters) - The incidence and severity of IYSV in onion seed crops in WA state was much less than in previous years, which probably reflects the exceptionally cool and moist conditions from early spring through mid-summer (end of July) in central WA. Most onion seed crops were harvested by early August, and thrips pressure was low through July, only increasing significantly in August when temperatures became exceptionally warm (warmest Aug. and Sept. in about 20 years for central WA, after the coolest April through July in the past ~50 years). No significant losses to IYSV were reported by onion seed crop stakeholders in WA in 2011. The disease was observed in many fields, but at low incidences and/or severities that did not result in economic losses. Similarly, although IYSV was observed in many onion bulb crops, there were no reports of significant economic injury from this disease. <br /> <br /> <br /> IYSV-plant and IYSV-vector interactions were studied to generate important information about the biology, pathogenicity, and epidemiology of the virus. Experimental hosts that provide differential response to IYSV infection were identified and described. This information will facilitate future studies on the nature of the host reaction to IYSV infection and the underlying factors that determine the outcome of IYSV infection. Role of onion thrips in virus epidemiology is being studied by determining the proportion of virus transmitters among field-collected thrips by using a rapid and sensitive, ELISA-based assay that targets a viral protein that could be found only upon viral replication in the insect. <br /> <br /> Efficacy of insecticides for thrips (primarily T. tabaci) control was examined in several trials. In a standard efficacy trial, Radiant performed the best, followed by Lannate and then Agri-Mek. In a trial evaluating organically approved insecticides, only Entrust was effective in reducing thrips densities. In trial that examined different sequences of insecticides applied throughout the season to manage thrips, many of the sequences worked well. Based on that study, the following recommendations were determined when early-season thrips populations are low or high. When low at beginning of season, the following sequence should be considered: Movento, Movento, Radiant Agri-Mek, Radiant and then Lannate. In contrast, if initial populations are high, the following sequence should be considered: Radiant, Movento, Movento, Radiant, Agri-Mek and Lannate.<br /> <br /> <br /> Objective 3. Transfer information on progress dealing with IYSV and thrips biology and IPM strategies to the onion industry and other interested parties. <br /> <br /> <br /> Colorado (H. F. Schwartz, W. Cranshaw, M. Bartolo, T. Gourd, B. Hammon)  Led the nationwide Onion ipmPIPE project and disseminated scouting information from all participants to stakeholders via the Onion ipmPIPE website. An 8-card set of diagnostic cards was produced with support from agribusiness donors, and 8,000 sets were distributed nationwide to project personnel, growers, consultants and others involved with agribusiness related activities. Topics were relevant to the W1008 and included Bulb Growth Stages, Storm Damage Effects, Virus Diseases, Insect Pests, Soil-Borne Diseases, Bacterial Diseases, Foliar Fungal Diseases, and Storage Fungal Diseases. Conference calls among participants of the Onion ipmPIPE project were held every two weeks during the season. Thrips and disease scouting information collected by participants can be found at the following website: http://apps.planalytics.com/aginsights/pipehome.jsp.<br /> <br /> <br /> Idaho (S.K. Mohan and R.S. Sampangi)  Participated in the Onion ipmPIPE project and disseminated information to growers. <br /> <br /> <br /> Michigan (M. Hausbeck and J. Morrice) - Participated in the Onion ipmPIPE project. Additionally, pocket guides were disseminated to 100 growers and biweekly visits were made to 11 sentinel plots to identify pests. Information was conveyed to growers.<br /> <br /> <br /> New Mexico (M. Uchanski) - Participated in the Onion ipmPIPE project and disseminated information to growers. <br /> <br /> <br /> New York (B. Nault, C. Hoepting, C. Hsu and S. Beer) - Several meetings were held in 2010 to inform NYs onion industry about results from this project: the Empire State Fruit and Vegetable EXPO in Syracuse in January, the Onion School in Middleburg in March, the Oswego Twilight Meeting in June and the Elba Muck Onion Meeting in Elba in August. Information pertaining to this subject was also presented at the Mid-Atlantic Fruit and Vegetable EXPO in Harrisburg, PA in February and the Wisconsin Potato and Onion Annual Meeting in Stevens Point, WI in February. Also, we participated in the Onion ipmPIPE project, shared results with growers and submitted scouting information on pests and diseases for inclusion on the Onion IPM PIPE website.<br /> <br /> <br /> Utah (D. Alston, D. Drost and C. Nischwitz)  Participated in the Onion ipmPIPE project. Five sentinel plots and five survey sites in the Davis, Weber, and Box Elder County production onion areas in Utah were monitored by Bonnie Bunn. Fields were assessed from early June till early September for thrips, other insects, and IYSV. Reports were submitted periodically, along with regional reports summarizing weather conditions, Sentinel Plot reports, and other insect and disease observations. Several meetings were held in 2010 to inform Utahs onion industry about results from this project. These included the Utah Onion Associations winter educational meetings (Feb. 15), the summer onion field day (Aug 16), and the fall onion association board meeting (Nov. 29).<br /> <br /> <br /> Washington  Participated in the Onion ipmPIPE project. Five sentinel plots in the Columbia Basin of Washington State were monitored by Tim Waters and Carrie Wohleb, WSU Extension Educators, twice monthly for thrips counts and other insects. Reports were submitted twice monthly, along with regional reports summarizing weather conditions, Sentinel Plot reports, and other insect and disease observations, by Lindsey du Toit, WSU vegetable seed pathologists. For details of the WA reports, refer to the Onion ipmPIPE website.<br />

Publications

Beer, S. V., Zaid, A. M., and Bonasera, J. M. 2011. Studies of bacterial problems of onion in New York  2010. Onion World 27:(3) 12-15.<br /> <br /> <br /> Boateng, C.O., and Schwartz, H.F. 2010. Relationships of Iris yellow spot virus and onion thrips (Thrips tabaci) to onion production and yield. Allium and Umbelliferae Improvement Newsletter Vol. 20:16-20.<br /> <br /> <br /> Buckland, K. 2011. Evaluating Fertilizer Rate, Crop Rotation, and Trap Crops for Effects on Onion Growth and Yield, Soil Health, Thrips Densities, and Iris Yellow Spot Virus Incidences. M.S. Thesis. Utah State University.<br /> <br /> <br /> Cramer, C.S., Bag, S., Schwartz, H.F., and Pappu, HR. 2011. Susceptibility of onion relatives (Allium spp) to Iris yellow spot virus. Plant Disease 95:1319.<br /> <br /> <br /> Diaz-Montano, J., Fuchs, M., Nault, B.A., Fail, J., and Shelton, A.M. 2011. Onion thrips (Thysanoptera: Thripidae): A global pest of increasing concern in onion. J. Econ. Entomol. 104(1): 1-13.<br /> <br /> <br /> Hsu, C., Hoepting, C.A., Fuchs, M., Smith, E., and Nault, B.A. 2011. Sources of Iris yellow spot virus in New York. Plant Disease 95: 735-743.<br /> <br /> <br /> Hsu, C. L., Reiners, S., Hoepting, C.A., and Nault, B.A. 2011. Relationship between nitrogen rate, thrips and yield in New York, 3 pp. In: Proceedings of the 2011 Empire State Fruit and Vegetable Expo. January 25-27, 2011. Syracuse, NY. Cornell Cooperative Extension and New York State Vegetable Growers Association.<br /> <br /> <br /> Jensen, L.B., Shock, C.C., and Saunders, M. 2011. Insecticide rotation trial for maximum efficacy against thrips in dry bulb onions, 2010, pp. 92-97. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2010, Department of Crop and Soil Science Ext/CrS 132.<br /> <br /> <br /> Jensen, L.B., Shock, C.C., and Saunders, M. 2011. Maximizing the economic value of insecticide applications for thrips control  A two-year study, pp. 104-116. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2010, Department of Crop and Soil Science Ext/CrS 132.<br /> <br /> <br /> Mohseni-Moghadam, M., Cramer, C.S., Steiner, R.L., and Creamer, R. 2011. Evaluating winter-sown onion entries for Iris yellow spot virus susceptibility. HortScience 46:1224-1229.<br /> <br /> <br /> Nault, B. A., and Hessney, M.L. 2011. Onion thrips control in onion  Trial I, 2010. Arthropod Management Tests, 2010. 36: E51.<br /> <br /> <br /> Nault, B. A., and Hessney, M.L. 2011. Onion thrips control in onion  Trial II, 2010. Arthropod Management Tests, 2010. 36: E52.<br /> <br /> <br /> Nault, B. A., and Shelton, A. M. 2011. Onion thrips management in onions: Consider before you spray. Cornell Cooperative Extension, Cornell Vegetable Program. Veg Edge (5): 6-9.<br /> <br /> <br /> Nault, B., Cranshaw, W., and Alston, D. 2011. Onion Insect Pests. Onion ipmPIPE Diagnostic Pocket Series - 2 page diagnostic card, distributed nationally): http://www.alliumnet.com/IPMPipe.html <br /> <br /> <br /> Nault, B.A., Hsu, C.L., and Hoepting, C. 2011. Maximizing performance of new insecticides for managing onion thrips in onion, 4 pp. In: Proceedings of the 2011 Wisconsin Potato and Onion Meeting. February 1-2, 2011. Stevens Point, WI. Wisconsin Potato and Vegetable Growers Association.<br /> <br /> <br /> Nault, B.A., Hsu, C.L., and Hoepting, C. 2011. Maximizing the level of onion thrips control using insecticides, 4 pp. In: Proceedings of the 2011 Mid-Atlantic Fruit and Vegetable Convention. February 1-3, 2011. Hershey, PA. Pennsylvania Vegetable Growers Association.<br /> <br /> <br /> Pappu, H. R. 2011. Virus Diseases. Onion ipmPIPE Diagnostic Pocket Series - 2 page diagnostic card, distributed nationally): http://www.alliumnet.com/IPMPipe.html <br /> <br /> <br /> Shock, C.C., and Wang, F.-X. 2011. Soil water tension, a powerful measurement for productivity and stewardship. HortScience 46: 178-185.<br /> <br /> <br /> Shock, C.C., Feibert, E.B.G., and Taberna, J. 2011. Effect of timing of harvest on onion yield and storability, pp. 70-76. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2010, Department of Crop and Soil Science Ext/CrS 132. http://www.cropinfo.net/AnnualReports/2010/OnionTiming.html.<br /> <br /> <br /> Shock, C.C., Feibert, E.B.G., Saunders, L.D., Jensen, L.B., Mohan, S.K., Sampangi, R.S., and Pappu, H.R. 2011. Management of onion cultural practices to control the expression of Iris Yellow Spot Virus, pp. 23-41. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2010, Department of Crop and Soil Science Ext/CrS 132. http://www.cropinfo.net/AnnualReports/2010/OnionIYSV.html.<br /> <br /> <br /> Shock, C.C., Feibert, E.B.G., Saunders, L.D., Jensen, L.B., Mohan, S.K., Sampangi, R.S., and Pappu, H.R. 2011. 2010 onion variety trials, pp. 14-22. In Shock C.C. (Ed.) Oregon State University Agricultural Experiment Station, Malheur Experiment Station Annual Report 2010, Department of Crop and Soil Science Ext/CrS 132. http://www.cropinfo.net/AnnualReports/2010/OnionVariety.html.<br /> <br /> <br /> Smith, E. A., DiTommaso, A., Fuchs, M., Shelton, A.M., and Nault, B.A. 2011. Weed hosts for onion thrips (Thysanoptera: Thripidae) and their potential role in the epidemiology of Iris yellow spot virus in an onion ecosystem. Environ. Entomol. 40(2): 194-203.<br /> <br /> <br /> Srinivasan, R., Diffie, S., Sundaraj, S., Mullis, S. W., Riley, D., Gitaitis, R., and Pappu, H. R. 2011. Evaluation of Lisianthus as an indicator host for Iris yellow spot virus. Plant Dis. 95:1520-1527.<br /> <br /> <br /> Srinivasan, R., Guo, F., Riley, D., Diffie, S., Gitaitis, R., Sparks, A., Jr., and Jeyaprakash, A. 2011. Assessment of variation among Thrips tabaci populations from Georgia and Peru based on polymorphisms in mitochondrial cytochrome oxidase 1 and ribosomal ITS2 sequences. J. Entomol. Sci. 46:191-203.<br /> <br /> <br /> Szostek, S. A., and Schwartz, H. F. 2011. A new research technique for thrips and IYSV. Onion World, Vol. 27:14-15.<br /> <br /> Waters, T., and Walsh, D. 2011. Thrips control in onion, pp. 10-11. Washington State University Onion Cultivar Field Day, 26 August 2011, Skone & Connors Produce, Frenchman Hills, WA. <br /> <br /> Waters, T. 2011. Thrips control in onion. Presentation at 25th Pacific Northwest Vegetable Association Annual Convention & Trade Show, 16-17 November 2011, Kennewick, WA. http://www.pnva.org/files/files/ThripsControlinOnion-Tim.pdf <br /> <br /> <br /> Zaid, A. M., Bonasera, J. M. and Beer, S. V. 2011. First Report of Enterobacter Bulb Decay of Onions Caused by Enterobacter cloacae in New York. Plant Disease 95:1581.<br /> <br /> <br /> <br /> <br /> Other Activities<br /> <br /> 1. Research Reports: Abstracts and Papers at International Professional Meetings <br /> <br /> None reported.<br /> <br /> <br /> <br /> <br /> 2. Research Reports: Abstracts and Papers at National Professional Meetings <br /> <br /> Boateng, C.O., and Schwartz, H.F. 2011. Effects of Iris yellow spot virus and Onion Thrips on onion physiology, growth and productivity. Proc. National Meeting of the American Phytopathological Society, Honolulu, HI, August 6-10, 2011. Poster Presentation.<br /> <br /> <br /> Boateng, C.O., Schwartz, H.F., and Otto, K. 2011. Onion cultivar resistance to Iris yellow spot virus and Onion Thrips in Colorado. Proc. National Meeting of the American Phytopathological Society, Honolulu, HI, August 6-10, 2011. Poster Presentation. <br /> <br /> <br /> Cramer, C.S. 2011. Evaluation of onion plant introduction accessions for leaf characteristics, onion thrips number per plant, and Iris yellow spot disease severity. HortScience 46:S280. (Abstr.).<br /> <br /> <br /> Cramer, C.S. 2011. In search of onion germplasm tolerant to Iris yellow spot virus. HortScience 46:S281. (Abstr.).<br /> <br /> <br /> Cramer, C.S. 2011. (SCRI-3) Evaluation of onion plant introduction accessions for leaf characteristics, onion thrips number per plant, and Iris yellow spot disease severity. HortScience 46:S294. (Abstr.).<br /> <br /> <br /> Cramer, C.S. 2011. In search of onion germplasm tolerant to Iris yellow spot virus. 5th Annual Plant Breeding Workshop. Annual Meetings of the Plant Breeding Coordinating Committee and National Association of Plant Breeders. May 23-25, 2011. College Station, TX. p. 13.<br /> <br /> <br /> Cramer, C.S. 2011. Screening winter-sown onion entries for Iris yellow spot virus resistance. W1008: Biology and management of Iris yellow spot virus (IYSV) and thrips in onions. Regional research project annual meeting. Las Cruces, NM. Dec. 8-9, 2011.<br /> <br /> <br /> Feibert, E.B.G., Shock, C.C., Saunders, L.D., and Simerly, B. 2011. Early Onion Harvest Options in the Pacific Northwest. Annual Conference of the American Society for Horticultural Science, 25-28 September 2011. Waikoloa, HI.<br /> <br /> <br /> Hsu, C., Hoepting, C., Fuchs, M., Shelton, A.M., and Nault, B.A. 2011. Changes in the spatial distribution of onion thrips (Thrips tabaci) and Iris yellow spot virus in onion fields over time. Entomological Society of America Annual Meeting, November 13, 2011. Reno, NV. Invited workshop presentation.<br /> <br /> <br /> Hsu, C., Hoepting, C., Fuchs, M., Shelton, A.M., and Nault, B.A. 2011. Changes in the spatial distribution of onion thrips (Thrips tabaci) and Iris yellow spot virus in onion fields over time. Entomological Society of America Annual Meeting, November 15, 2011. Reno, NV. Poster presentation.<br /> <br /> <br /> Nault, B. A. 2011. Thrips IRM in onions. Entomological Society of America Annual Meeting, November 15, 2011, Reno, NV. Invited symposium presentation.<br /> <br /> <br /> Nault, B.A., and Shelton, A.M. 2011. IPM for onion thrips (Thrips tabaci) in onion. Entomological Society of America Annual Meeting, November 13, 2011. Reno, NV. Invited workshop presentation.<br /> <br /> <br /> Shelton, A.M., and Nault, B.A. 2011. Spatial and temporal insecticide resistance in onion thrips (Thrips tabaci) populations in onions. Entomological Society of America Annual Meeting, November 13, 2011. Reno, NV. Invited workshop presentation.<br /> <br /> <br /> Shock, C.C., Feibert, E.B.G., Saunders, L.D., Jensen, Pappu, H., L.B., Mohan, S.K. and Sampangi, R.S. 2011. Influence of Selected Cultural Practices on the Expression of Iris yellow spot virus in Onion. Annual Conference of the American Society for Horticultural Science, 25-28 September 2011. Waikoloa, HI.<br /> <br /> <br /> Smith, E. A., DiTomasso, A., Fuchs, M., Shelton, A.M., and Nault, B.A. 2011. Weed hosts of onion thrips (Thrips tabaci) and implications for Iris yellow spot virus epidemiology in onion, Entomological Society of America  Eastern Branch Meeting, March 20, 2011, Harrisburg, PA. Asa Fitch Award Winner Presentation.<br /> <br /> <br /> <br /> <br /> 3. Reports at Grower meetings and field days<br /> <br /> Alston, D. 2011. Insecticide rotations for onion thrips suppression. Utah Onion Association winter meeting, Brigham City, Utah. February 15, 2011.<br /> <br /> <br /> Cramer, C.S. Screening winter-sown onion entries for Iris yellow spot virus resistance. New Mexico Dry Onion Commission meeting. Las Cruces, NM. March 10, 2011.<br /> <br /> <br /> Cramer, C.S. Screening onion entries for tolerance/resistance to Iris yellow spot virus. NM Onion Field Day. Las Cruces, NM. July 20, 2011.<br /> <br /> <br /> Drost, D. 2011. Growing Onions in a Reduced Nitrogen System: Effects on Productivity and Thrips. Empire State Fruit and Vegetable EXPO. Syracuse, NY. January 27, 2011.<br /> <br /> <br /> Drost, D. 2011. Nitrogen and a Whole Farm Approach to Iris Yellow Spot Virus Management. Utah Onion Association winter meeting, Brigham City, Utah. February 15, 2011.<br /> <br /> <br /> Feibert, E.B.G. and Shock, C.C. 2011. Effect of timing of harvest on onion yield and storability. Malheur County, Oregon and Idaho Onion Growers Annual Meeting. Ontario, OR. February 1, 2011.<br /> <br /> <br /> Hsu, C. L., Nault, B. A., Reiners, S., and Hoepting, C.A. 2011. Reduced inputs workshop: Relationship between nitrogen fertilizer rate, onion thrips and yield in NY. Empire State Fruit and Vegetable EXPO. Syracuse, NY. January 27, 2011.<br /> <br /> <br /> Jensen, L.B., E.B.G. Feibert, and C.C. Shock. 2011. Onion thrips research. Malheur County, Oregon / Idaho Onion Growers 51st Annual Meeting. Ontario, OR. February 1, 2011.<br /> <br /> <br /> Nault, B.A., Hsu, C.L. and Hoepting, C.A. 2011. Do tank mixes of insecticides and fungicides affect thrips control? Empire State Fruit and Vegetable EXPO. Syracuse, NY. January 27, 2011. <br /> <br /> <br /> Nault, B.A., Hsu, C.L. and Hoepting, C.A. 2011. Maximizing the level of onion thrips control using insecticides. Mid-Atlantic Fruit and Vegetable Convention. Hershey, PA. February 1, 2011. <br /> <br /> <br /> Nault, B.A., Hsu, C.L. and Hoepting, C.A. 2011. Maximizing insecticide use to manage onion thrips on onion. University of Wisconsin Extension and Wisconsin Potato and Vegetable Growers Association Grower Conference. Stevens Point, WI. February 2, 2011. <br /> <br /> <br /> Nault, B.A., Hsu, C.L., and Hoepting, C.A. 2011. Onion thrips management: Preserving insecticides as an effective strategy. Orange County Onion School. Middletown, NY. March 2, 2011. <br /> <br /> <br /> Nault, B.A., Hsu, C.L., and Hoepting, C.A. 2011. Impact of co-applications of insecticides and fungicides on thrips control in onion. Disease and insect update meeting sponsored by Syngenta Crop Protection. Dundee, NY. March 23, 2011.<br /> <br /> <br /> Nault, B.A. 2011. Update on onion insect pests. Oswego County Onion Growers Twilight Meeting. Cornell Cooperative Extension of Oswego County. Oswego, NY. June 22, 2011.<br /> <br /> <br /> Nault. B.A., Hsu, C.L., and Fok, E. 2011. Latest developments in management of onion thrips management. 2011 Elba Muck Onion Twilight Meeting. Cornell Cooperative Extension and Cornell Vegetable Program. Elba, NY. August 2, 2011.<br /> <br /> Nischwitz, C. 2011. Management of IYSV: Targeting Thrips Reproductive Hosts and IYSV Reservoirs in the Farmscape - New Research Project. Utah Onion Association winter meeting. Brigham City, Utah. February 15, 2011.<br /> <br /> <br /> Reeve, J. 2011. Cultural Management of Onion Thrips and Iris Yellow Spot Virus. Utah Onion Association winter meeting. Brigham City, Utah. February 15, 2011.<br /> <br /> <br /> Reitz, S. R. 2010. New pest management concerns in vegetable production. Gadsden County Tomato Forum, Quincy, FL. December 2010.<br /> <br /> <br /> Schwartz, H. F. 2011 Onion virus management and updates. Annual Education Meeting of the Colorado Onion Association. Eaton, CO. January 27, 2011.<br /> <br /> <br /> Schwartz, H. F. 2011. Onion virus management and updates. Annual Field Day of the Colorado Onion Association. Brighton, CO. September 8, 2011.<br /> <br /> <br /> Schwartz, H. F. 2011 Onion virus and other disease/insect pest management and updates. Summer Meeting of the National Onion Association. Reno, NV. July 21, 2011.<br /> <br /> <br /> Shock, C.C., Feibert, E.B.G., Saunders, L.D., Jensen, L.B., Mohan, S.K., Sampangi, R.S., and Pappu, H.R. 2011. Irrigation, N fertilization and varietal effects on the expression of Iris Yellow Spot Virus in onion. Malheur County, Oregon and Idaho Onion Growers Annual Meeting. Ontario, OR. February 1, 2011.<br /> <br /> <br /> Shock, C.C., Feibert, E.B.G., Saunders, L.D., Jensen, L.B., Mohan, S.K., Sampangi, R.S., and Pappu, H.R. 2011. Onion variety trial report, 2010. Malheur County, Oregon and Idaho Onion Growers Annual Meeting. Ontario, OR. February 1, 2011.<br /> <br /> <br /> Shock, C.C., Feibert, E.B.G., Saunders, L.D., Jensen, L.B., Mohan, S.K., Sampangi, R.S., and Pappu, H.R. 2011. Irrigation, N fertilization and varietal effects on the expression of Iris Yellow Spot Virus in onion. Malheur County, Oregon and Idaho Onion Growers Annual Meeting. February 1, 2011. Ontario, OR.<br /> <br /> <br /> Shock, C.C., Feibert, E.B.G., Saunders, L.D., Jensen, L.B., Mohan, S.K., Sampangi, R.S., and Pappu, H.R. 2011. Onion variety trial report, 2010. Malheur County, Oregon and Idaho Onion Growers Annual Meeting. February 1, 2011. Ontario, OR.<br /> <br /> <br /> Shock, C.C., Feibert, E.B.G., Saunders, L.D., Mohan, S.K., Sampangi, R.S., and Pappu, H.R. 2011. Management of IYSV. Summer Farm Festival and Annual Field Day, OSU Malheur Experiment Station. 13 July 2011. Ontario, OR. <br /> <br /> <br /> Waters, T.D. 2011. Insect Management of Onions in Washington. Pacific Northwest Insect Management Conference. Portland, OR. January 10, 2011.<br /> <br /> <br /> Waters, T.D. 2011. Thrips Control in Dry Bulb Onion. Columbia Basin Crop Consultants Association Short-Course. Moses Lake, WA. January 20, 2011.<br /> <br /> <br /> Waters, T.D. 2011. Insect Pest Management of Onion. Walla Walla Sweet Onion Growers Meeting. Walla Walla, WA. January 24, 2011.<br /> <br /> <br /> Waters, T.D. 2011. Onion Research Project Update and Review. Clearwater Supply Growers Meeting. Othello, WA. February 24, 2011.<br /> <br /> <br /> Waters, T.D. 2011. Thrips Control in Dry Bulb Onions in Washington State.<br /> Western Region County Agricultural Agents Meeting. Kennewick, WA. October 12, 2011.<br /> <br /> <br /> Waters, T.D. 2011. Insect Management of Onions in the Pacific Northwest.<br /> Hermiston Area Farm Fair. Hermiston, OR. December 2, 2011.<br /> <br /> <br /> <br /> <br /> Internet Resources<br /> <br /> Onion Disease Management strategies, reports and publications, including those on IYSV and thrips. http://www.colostate.edu/Orgs/VegNet/vegnet/onions.html<br /> <br /> <br /> Onion ipmPIPE and Disease Diagnostics, including those on IYSV and thrips, in addition to other resources such as weather, forecasts, markets: http://apps.planalytics.com/aginsights/pipehome.jsp <br /> <br /> <br /> Schwartz, H. F. 2011. Web site dedicated to information and resources on onion pest management and/or thrips and IYSV. http://www.alliumnet.com/index.htm<br /> <br /> <br /> <br /> <br /> Other Related Activities<br /> <br /> New York (B. Nault) - Submitted a package to the New York State Department of Environmental Conservation (NYSDEC) for their consideration of a Specific Emergency Exemption (FIFRA Section 18) for the use of spirotetramat (Movento) on onion for onion thrips control for the 2011 season. The Crisis Exemption request was granted by NYSDEC from June- September 2011. Additionally, a second package was submitted to the NYDEC for their consideration of a Section 18 for the use of abamectin (Agri-Mek 0.15EC) on onion for onion thrips control for the 2011 season. The Crisis Exemption request was granted by NYSDEC from June- September 2011.<br />

Impact Statements

1. A conservative estimate of 10% yield loss to the U.S. onion industry due to the combined effects of thrips and IYSV damage, as well as the cost of mitigation (insecticides) was valued at more than 75 million dollars during 2011. The following activities and accomplishments of the W1008 project participants have individually and collectively contributed to reducing these negative impacts on U.S. onion growers and the industry at large.
2. As a result of this project, onion breeders, plant pathologists, entomologists, virologists and integrated pest management specialists are providing research-based information to onion growers that have helped them more effectively manage thrips and IYSV.
3. Advancements in identifying onion lines that are less susceptible to thrips and IYSV damage are being used in onion breeding programs for developing new onion cultivars that will be more effective than existing tolerant cultivars for mitigating yield losses caused by thrips and IYSV.
4. Growers are adopting onion varieties that have greater tolerance to thrips and IYSV.
5. New and selective insecticides and application strategies identified from this project were adopted by growers that kept onion thrips populations under control, decreasing the frequency of sprays applied per season and reducing control costs and the threat of insecticide resistance. More growers are using selective insecticides to control thrips, especially early in the season, and this change in insecticide use might be allowing natural predators to help control thrips.
6. Due to better knowledge of the transmission of IYSV, fewer growers are planting over-wintering onions. With fewer overwintering onions and better cull onion disposal, growers are breaking the natural green bridge keeping IYSV pressure high from one production year to the next. Some growers continued to suffer IYSV related yield losses due to over-wintering onion bulb or seed fields close to their summer production fields.
7. In Utah, growers using low nitrogen input system (130-150 lb. N/A) reported they applied 0-1 insecticide sprays in 2010 which saved them nearly $200/A compared to growers using the normal N input amounts of 250 lb. N/A.
8. In the Idaho-Oregon Treasure Valley, IYSV has declined from 2005/2006 levels as growers practice greater vigilance in destroying onion culls and planting over-wintering fields further from summer production fields, actions that help to break the natural bridge that can perpetuate IYSV infestations.

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