Brief Summary of Minutes of Annual Meeting

Objective 1. Evaluate onion germplasm for greater levels of tolerance to Iris yellow spot virus (IYSV), other pathogens and thrips. Colorado (H. Schwartz, S. Szostek, W. Cranshaw, M. Bartolo, T. Gourd, B. Hammon) – During 2014 the Colorado team confirmed that the following germplasm expressed significantly greater plant vigor after season-long exposure to thrips at Fort Collins; and include PI 264320, 264648, 288903, 546106, and 546192. These PIs have shown tolerance to thrips and IYSV in previous tests in Colorado; and have performed equal to or better than the cultivar Advantage. In 2013, several widely-grown onion varieties were evaluated for their total phenolic content. Samples were taken from University-sponsored trials conducted in northern Colorado, southern Colorado, and the Columbia Basin of central Washington. Samples encompassed popular yellow, white, and red-skinned varieties. Across the geographical locations, the yellow-skinned variety “Granero” had the highest total phenolic content and the white-skinned variety “Cometa” had the lowest content. Two onion cultivars, the yellow-skinned variety “Vaquero” and the red-skinned variety “Redwing” were evaluated in an anticancer assay by altering the diet of laboratory rodents. In an aggressive in vivo model for breast cancer, “Vaquero” had protective activity and “Redwing” had some, but significantly less activity. Georgia (R. Gitaitis, B. Dutta, and B. Srinivasan) – No efforts have been made in this area in Georgia as our annual germplasm trial is conducted using short day onions that are grown throughout the fall and winter. In general temperatures are too low for expression of IYSV thus ratings typically cannot be made. New Mexico (C. Cramer) – Sixty-nine onion breeding lines selected for reduced Iris yellow spot (IYS) disease symptom expression, 7 plant introduction (PI) accessions from the U.S. germplasm collection, 7 experimental breeding lines from the New Mexico State University (NMSU) breeding program, and 2 commercial cultivars were evaluated for the number of thrips per plant and IYS disease symptoms. Fourteen selected lines exhibited a lower IYS disease incidence than ‘Rumba’ at 13 weeks after transplanting. At 16 weeks, six selected lines exhibited a lower disease incidence than their parental line, NMSU 07-53-1. Five selections of different lines were made this year from this material. Seeds of 72 different lines were produced in this year. New York (B. Nault, S. Beer and C. Hoepting) – A combination of a thrips-resistant cultivar (cv. ‘Advantage’) and insecticide applications timed using action thresholds was evaluated in a commercial onion field in 2014. The onion thrips infestation occurred later in the season and was lower than typical. Thrips were controlled effectively in small-field plots of ‘Advantage’ and in the thrips-susceptible cultivar, ‘Santana’, following either a weekly insecticide spray program or an action threshold program. However, fewer insecticide applications were applied in the action threshold program compared with the weekly spray program, especially for ‘Advantage’. Season total densities of onion thrips in untreated plots were similar between ‘Advantage’ and the ‘Santana’. Despite the similar densities of thrips in the two cultivars, damage levels were much lower in ‘Advantage’ than in ‘Santana’. The reason for this difference is not understood, but may be explained by differences where thrips feed on the two cultivars and/or the larger canopy of ‘Advantage’ compared with ‘Santana’, which would result in a smaller proportion of the ‘Advantage’ canopy being damaged by thrips. Marketable bulb yield for ‘Advantage’ was similar between the insecticide treatments and untreated control, indicating that the low levels of thrips damage to ‘Advantage’ was not enough to reduce bulb yields. Unlike previous years, marketable yield of ‘Santana’ in untreated plots also did not differ from insecticide-treated plots; thrips damage occurred very late in the season and apparently did not reduce bulb yield. Oregon (S. Reitz, C. Shock, E. Feibert, and M. Saunders) – Early maturity and full season onion variety trials were conducted in 2014 with support of Idaho-Eastern Oregon Onion Committee and various seed companies. The full season varieties were grown under both furrow and drip irrigation. All varieties were evaluated for their yield, maturity and susceptibility to thrips damage and IYSV. Varieties had significant differences in IYSV in 2014. Utah (D. Drost) - Thirty-six commercially available Spanish onion cultivars from seven companies were assessed for growth, productivity, maturity and rated for IYSV. Symptom expression of IYSV in 2014 was low; however, all varieties evaluated showed visual evidence of IYSV under field conditions. IYSV did not appear to impact bulb yield. Further evaluation of materials will occur in late January 2015 to assess rots and weight losses in storage. Work on correlations between IYSV incidence and storage losses needs additional evaluation when resources become available. Findings will be posted on USU website and preliminary findings were distributed to local growers and industry representatives in late December 2014. Objective 2. Investigate thrips biology and IYSV epidemiology to improve management strategies. Colorado (H. Schwartz, S. Szostek, W. Cranshaw, M. Bartolo, T. Gourd, B. Hammon) – There is no evidence that IYSV is seed transmitted. Onion seed included in double antibody sandwich enzyme linked immunosorbent assays (DAS-ELISA) to detect IYSV occasionally yielded a positive result. IYSV was detected in the pedicels, petals, anthers, and fruits of onion flowers by reverse transcriptase polymerase chain reaction (RT-PCR). Onion seed collected from several cultivars of IYSV symptomatic plants was grown out under greenhouse and growth chamber conditions. IYSV was not detected in the six week old seedlings. Further investigation of onion seeds revealed IYSV could be detected in the seed coat, but not the emerging radicle. It is highly unlikely that IYSV can pass from the seed coat to the new plant during germination, and seeds remain an unlikely source of IYSV inoculum. IYSV distribution throughout onion leaves is uneven and patchy. A reverse transcription quantitative real time PCR was developed to compare relative amounts of IYSV within leaves and between cultivars. The amount of IYSV was greatest at the lesion site itself and decreased as distance from the lesion increased. No statistically significant differences were found in the amount of IYSV between susceptible cultivar Granero and tolerant cultivar Advantage. Georgia (R. Gitaitis, B. Dutta, and B. Srinivasan) – It was shown previously that tobacco thrips, Frankliniella fusca, could transmit Pantoea ananatis, causal agent of center rot of onion. Further investigations on the transmission of Pantoea agglomerans and Pantoea ananatis, both part of a group of organisms that cause the center rot complex, were conducted using onion thrips, Thrips tabaci, as the vector. This species of thrips acquired either bacterium in a similar manner. A small proportion of thrips (15-20%) acquired the bacteria after 1 hr of feeding and nearly 100% of the thrips acquired the bacteria after 48 hr of feeding. Additional experiments demonstrated that the bacteria could pass through the different developmental stages of thrips, including the pupal phase. Using fluorescent-labelled antibodies, we demonstrated that the bacteria remain localized in the thrips' gut and was not detected elsewhere in thrips' bodies and most importantly was not detected in the salivary glands or mouth. After feeding and acquisition, thrips' saliva and feces were collected and inoculated onto healthy onion seedlings. No transmission was observed with any of the saliva samples but transmission did occur with just using feces. It was speculated that the mode of transmission was contamination of feeding and other wounds via thrips' feces. Finally, it was demonstrated that if thrips were continually provided with a clean food source, their gut could be flushed clean of the contaminating bacteria within 5 days. New York (B. Nault, S. Beer and C. Hoepting) – During a week-long examination of thrips flight activity in August, we observed thrips dispersal occurring when temperatures were relatively warm (upper 70s) either at crepuscular morning or evening. Onion thrips populations collected from onion fields early in the season were genetically similar to those late in the season, suggesting that little mixing occurs from populations outside of onion. Additionally, the genetic population structure of onion thrips populations collected from onion and potato were completely different, despite the proximity of these crops to each other. Co-applications of insecticides (Agri-Mek, Movento and Radiant) with a non-ionic surfactant (Induce), a methylated seed oil (MSO), and mineral oils (PureSpray Green and JMS Stylet oil) were more effective for managing onion thrips than when these insecticides were used alone. Season-long management of onion thrips continues to be most effective using a series of products beginning with Movento (2 applications) followed by Agri-Mek (2 applications), and then Radiant (2 applications). The position of Exirel was examined in the middle and end of the sequence and both performed as well as the standard sequence shown above. An attempt was made to examine IYSV prevalence near potential sources for this virus: transplanted onion fields, weedy areas adjacent to onion fields, and onion cull piles (direct-seeded onion fields was the negative control). Lisianthus sp. was used as an indicator plant and these potted-plants were placed near these potential sources (n=5 locations per source; 20 plants per location). Lisianthus sp. plants were placed at sources for one week and then moved to a greenhouse for an additional week before determining whether it was infected with IYSV (June-Sept). No symptoms developed on plants and only a few tested positive for IYSV over the entire season. Oregon (S. Reitz, C. Shock, E. Feibert, and M. Saunders) – Two insecticide rotation trials were conducted to evaluate the effectiveness of various insecticides in managing thrips and IYSV. One trial included all foliar applied treatments and the other featured insecticides applied through drip irrigation and by ground. Thrips populations and onion bulb yield varied significantly between treatments, suggesting that thrips and IYSV are significant limiting factors for onion production. Movento and Agri-mek were effective in early season thrips management. The timing of Movento applications is critical so that sufficient levels are in the plant before large thrips populations have developed. Radiant remains the most effective insecticide for mid to late season thrips management. Other materials (e.g., Aza-direct and M-Pede tank mixes) do not always reduce thrips abundance but do contribute to higher yields. Drip applied products did not outperform foliar applied products, but these applications may reduce grower expenses but reducing overall application costs. Insecticide susceptibility trials were conducted by collecting onion thrips from commercial fields throughout the area and exposing them to one of four commonly used insecticides (Agri-mek, Lannate, Movento, Radiant), and demonstrate that populations remain susceptible to these chemicals. Utah (D. Alston, D. Drost and C. Nischwitz) - Thirty one (31) field sites surveyed in 2014 in the onion production areas of Davis, Weber, and Box Elder Counties, Utah. Fields were evaluated from June until September for thrips, other insects, and IYSV. Soils sampled and plant growth determined. Field productivity measured and details on production practices gathered from growers. Crop rotations (alfalfa, corn, wheat) and nitrogen management (lo-hi N) influences on onion growth and productivity, onion thrips pressure and IYSV incidence evaluated in research trials during 2014. Finding show that onions grown with reduced N had fewer thrips than when grown at average grower applied N levels. Onion growth (leaf number, weight, and yield) was not influence by nitrogen. IYSV was found in all treatments. Research will continue through 2017. Washington (H. R. Pappu, T. Waters, C. Wohleb, and L. J. du Toit) - Field plots of onion (var. ‘Sabroso’ Bayer Vegetable CropScience, Parma, ID) were established at the WSU Research Farm in Pasco, WA and grown using drip irrigation and standard grower practices for agronomic and pest management inputs excluding thrips treatments. Plots were established in a random complete block design with four replications. In each instance, plots were 7.5 feet wide and 30 feet long. Applications (except where specified) were made with a CO2 pressurized back pack sprayer applying 30 gallons of water carrier per acre at 35 psi. Efficacy was evaluated four or five days after applications by counting the number immature and adult thrips per plant on 10 individual plants per plot in the field. All data for each sample date were analyzed by ANOVA and treatments means were compared to thrips population means from non-treated control plots in pairwise t-tests. At the end of the growing season onion yield and size were evaluated for comparison among treatments. Trials were conducted to determine insecticide efficacy and determine the treatment threshold for thrips on onions in Washington. A global genetic analysis of known IYSV nucleocapsid gene (N gene) sequences was carried out to determine the comparative population structure, spatial and temporal dynamics with reference to its genetic diversity and evolution. A total of 98 complete N gene sequences available in GenBank and reported from 23 countries were characterized by in silico RFLP analysis. Based on RFLP, 94% of the isolates could be grouped into NL or BR types while the rest belonged to neither group. The relative proportion of NL and BR types was 46% and 48%, respectively. A temporal shift in the IYSV genotypes with a greater incremental incidence of IYSVBR was found over IYSVNL before 2005 compared to after 2005. The virus population had at least one evolutionarily significant recombination event, involving IYSVBR and IYSVNL. Genetic differentiation studies showed inherent differentiation and infrequent gene flow between IYSVBR and IYSVNL genotypes corroborating the geographical confinement of these genotypes. Taken together the study suggests that the observed diversity in IYSV population and temporal shift in IYSVBR genotype is attributable to genetic recombination, abundance of purifying selection, insignificant positive selection and population expansion. Objective 3. Investigate the biology, ecology and epidemiology of other pathogens to improve management strategies. Colorado (H. Schwartz, S. Szostek, W. Cranshaw, M. Bartolo, T. Gourd, B. Hammon) – Disease incidence of Pink Root was too light to separate out effects of any treatment with Quadris or Serenade. There were no effects of treatments on leaf number, plant weight or root weight measurements 60 days after planting. Xanthomonas leaf blight infection (incidence and severity) was reduced by timely applications of bactericides such as Kocide 3000, Badge and experimentals when compared to the untreated control which sustained 40 percent canopy damage by the end of the season. A field trial comparison of Fusarium oxysporum tolerance among forty onion varieties under field growing conditions was located in Brighton, Colorado.This field has a long history of Fusarium issues. The soil type was a sandy loam. Onions were last planted in this field in 2008, followed by field corn in 2009, cabbage in 2010, sweet corn in 2011, field corn in 2012, and cabbage in 2013. Forty onion varieties were planted in a randomized complete block with four replicates. Onion varieties showed significant differences in infection rates and overall plant health during the growing season. Final yield analysis of all 40 onion varieties showed significant differences among varieties, but the differences could not be solely attributed to Fusarium infection. This study also showed that visual infection assessments of Fusarium basal rot did not always give a clear picture of how market yield could be impacted under high disease pressure. One onion variety had a high Fusarium infection rate based on visual symptoms yet produced a higher yield, possibly indicating a higher tolerance to Fusarium. Georgia (R. Gitaitis, B. Dutta, and B. Srinivasan) – Management strategies for sour skin were studied. In particular predictive models using concentrations of the cations of copper, iron, manganese and zinc were correlated with sour skin severity. It was speculated that the cations are affecting superoxide dismutase enzymes which in turn detoxify reactive oxygen species. This begins a cascade of reactions resulting in the production of salicylic acid and up-regulation of NPR1 gene leading to systemic acquired resistance products. The predictive models may have use in identifying fields of potentially high risk for sour skin. In time, it is hoped that prescribed fertility "cocktails" could be formulated and applied to onions in the field to enhance innate resistance mechanisms. Idaho (B. Shroeder) - The development of the DNA macroarray for the detection of onion bulb rots specifically applies to W2008: 1) Develop a DNA macroarray for detecting and differentiating pathogens that can cause onion bulb rots in storage: It became clear quite early in the project that the DNA macroarray could not encompass both the fungal and the bacterial pathogens in a single test. Therefore the development of a fungal DNA macroarray to detect 14 fungi and a bacterial DNA macroarray to detect 12 bacteria capable of causing onion bulb rot will be discussed below. A DNA macroarray was developed to detect the onion bulb rot fungi, Aspergillus niger, Botrytis aclada, Botrytis allii, Botrytis byssoidea, Botrytis cinerea, Fusarium oxysporum, Fusarium proliferatum, Kluyveromyces marxianus var. marxianus as well as several species of Penicillium. Efforts have focused on optimizing the detection conditions to eliminate cross reaction among the target bacteria listed above as well as non-target organisms associated with onion bulbs. Currently, there is some cross reaction among the Pseudomonas strains on the bacterial DNA macroarray. It is not clear why this is occurring and it is being investigated. The sensitivity of the bacterial DNA macroarray has not been determined. 2) Evaluate and optimize the DNA macroarray for testing onion bulbs: The fungal DNA macroarray was able to detect the presence of fungal pathogens present in non-symptomatic onion bulbs, suggesting that it could be used to predict the risk of storage rots. It has not been determined if the bacterial DNA macroarray can detect bacterial plant pathogens present in non-symptomatic onion bulbs as latent infections. A manuscript describing this work is in preparation. New York (B. Nault, S. Beer and C. Hoepting) – Bacterial Diseases of Onion Progress was made in developing techniques to accurately and efficiently identify bacterial pathogens. Two approaches were addressed. In the first, the diversity among bacteria in the nucleotide sequence of the gyraseB gene was utilized to identify bacterial pathogens. This approach was fully described in a recent publication (J. Microbiological Techniques (2014) 103: 1387-143. In the second, pairs of highly specific primers for use in PCR were designed to produce amplicons useful for the identification of Pantoea ananatis, Burkholderia species and Enterobacter cloacae, the three major pathogens of onion in New York State. This approach has been thoroughly tested and a publication describing the technique is currently in draft form. We anticipate submitting it for publication in the coming months. A new approach to define the etiology of disease development by the three important bacterial pathogens of onion in New York was conceived and implemented on a trial basis during the 2014 growing season. The goals are to determine when during the growing season onions become infested and infected by the three bacteria and when they are susceptible to infection by artificial inoculation. The point of this approach is to provide specific bases to thwart the development of disease at the most opportune times during the growing season. OxiDate®, a pesticidal product of Biosafe Systems LLC, that is registered for use against bacterial diseases on onions in New York was evaluated in collaboration with a New York grower. Replicates stripes of onion plantings were sprayed with OxiDate® in a tank mix of fungicides and insecticides every week or 10 days beginning in late June until a few weeks before harvest in September. Strips in the same field were treated similarly except they were not sprayed with OxiDate® . The hypothesis was that the material would reduce the populations of Enterobacter cloacae sufficiently to reduce rot caused by the pathogen, which is harbored in the soil in which the onions are grown. No substantial differences were found in the population of Enterobacter cloacae in the strips treated with OxiDate® and those not treated with OxiDate® Fungal Diseases of Onion Stemphylium leaf blight (SLB) emerged as a very serious leaf disease of onion in New York during the 2012-2013 growing seasons. Although it is not understood why this endemic disease of onion has moved from its usual backseat position as a secondary pathogen into the front seat as an aggressive pathogen, it appears that SLB is now a serious contender in the onion leaf disease complex in New York. Starting in July, SLB lesions form on the oldest leaves and leaf dieback progresses quickly often resulting in the onions “dying standing up” before they are fully mature. When onions die standing up the neck tissue does not seal and the bulbs tend to be of poorer quality. Downy mildew (DM) is a sporadic disease of onion in New York, which is favored by cooler temperatures and long periods of dew, and typically does not occur until late August. When it occurs in July, it has plenty of time to progress and spread causing excessive leaf dieback and the onions to die standing up. Occurrence of DM in July has increased in recent years. In general, in commercial onion production in New York, SLB pressure was lower in 2014 than it had been in the previous years. Although growers adjusted their fungicide programs to include fungicides with good activity against SLB, the relatively stress-free growing conditions likely played a role in preventing SLB from getting a good foothold. Oregon (S. Reitz, C. Shock, E. Feibert, and M. Saunders) – The United States Food and Drug Administration (FDA) has proposed draft rules to implement the Food Safety Modernization Act (FSMA). As part of FSMA, the FDA has proposed that plastic totes be substituted for wooden bins for the storage of onion bulbs as a means to reduce the risk of contamination of onions with potential human pathogens. The project started as a way to address the Food safety Modernization Act (FSMA) agricultural water quality rules. The FDA published proposed revisions to the rules at the end of September 2014. Because we will not know what the final rules are until late in 2015, we felt it was important to continue with research on ways to reduce E. coli levels in case that would be needed under the final rules. Although the final FSMA rules have not been published, we wished to determine if certain crop management and maintenance methods growers already use could be adapted for managing E. coli. The three different options for managing E. coli that we examined were: 1) Chlorine dioxide in drip irrigation systems. Injections of chlorine dioxide are used to control the growth of algae in drip irrigation lines. We found that current rates of chlorine dioxide virtually eliminate E. coli. Lower rates also significantly reduce E. coli levels far below proposed FDA standards of 126 CFU / 100 ml. 2) Copper Sulfate added to irrigation ditches. Copper sulfate can also be used to help control algae growing in irrigation ditches. We found that copper sulfate almost completely eliminates E. coli (we measured E. coli at several points along the irrigation ditch and at the end of furrows in a field). 3) Copper based fungicides and bactericides are used to manage onion diseases and improve onion storage quality. We examined the use of a late season application of a copper based fungicide to treat E. coli that may be on the onion bulbs in the field. We could not judge the effectiveness of this treatment because onions had no E. coli before the treatment was made, suggesting that onions are not likely to acquire E. coli. Pennsylvania (B. Gugino) – During the past 5 to 10 years, bacterial bulb decay, caused by a number of different bacterial pathogens, has assumed much greater importance in the Northeast region. In PA and NY, annual losses range from 5 to 40%. However, these losses are variable, between fields and within the same field; in many cases the full extent of disease losses is not evident until harvest or after post-harvest storage. In part this is because bacterial bulb decay often affects only a single internal scale while outer scales remain firm, such infected bulbs are virtually impossible to detect. Such onions are shipped and consequently rejected, which often results in entire loads being dumped, despite only a small percentage of bulbs being infected. In order to develop an integrated pest management plan it is important to understand what factors are associated with increased bacterial disease. One key factor is identifying where the bacterial pathogens are coming from (transplants, weeds, soil, etc.) so that management efforts can be directed towards excluding or reducing the pathogen from the field. The analysis of data collected from a large scale on-farm replicated plot survey conducted in 2011 and 2012 was completed in 2014 as part of a PhD dissertation in Plant Pathology by Emily Pfeufer. Results from this research have demonstrated that in PA, transplants and weeds can be potential sources of bacterial pathogen inoculum. In PA, the predominant bacterial pathogens were Pectobacterium carotovorum subsp. carotovorum, Pantoea agglomerans, and Pseudomonas marginalis pv. marginalis. In NY, Burkholderia cepacia was most commonly identified from symptomatic bulbs at harvest, followed by Enterobacter cloacae and Pantoea ananatis. Transplants and weeds were not surveyed for bacteria pathogenic to onion in NY. However, B. cepacia was identified in 83% of the soil samples collected in the NY survey. Texas (O. Alabi) – During the 2013/2014 cropping season, a total of 25 onion fields spread across the Lower Rio Grande Valley (LRGV) of South Texas were surveyed for foliar pathogens of onions. At each location, overall visual assessment of disease was determined and four representative plants selected across the field for more detailed assessment and laboratory analysis. Pink root (Phoma terrestris) and stemphylium leaf blight (Stemphylium vesicarium) were recorded in 100 and 96 plants, respectively from all 25 fields indicating that both were the most predominant diseases of onions during the 2013/2014 growing season in the LRGV. They were followed by downy mildew (Peronospora destructor) in 38 plants from 13 fields, gray mold (Botrytis spp.) in 37 plants from 17 fields, purple blotch (Alternaria porri) in 30 plants from 14 fields, powdery mildew (Leveillula taurica) in 22 plants from 10 fields and iris yellow spot disease (Iris yellow spot virus) in 15 plants from 7 fields. Given that favorable environmental conditions for these diseases exist in the LRGV at different times during the onion growing season, the results point to the need for an integrated management strategy that takes into account avoidance of inoculum sources and timely applications of recommended fungicides to reduce initial infection and secondary development by fungal pathogens. Objective 4. Facilitate interaction and information transfer between W2008 participants, the onion industry and other stakeholders. Georgia (R. Gitaitis, B. Dutta, and B. Srinivasan) – The information in categories 2 & 3 was presented at the National Alliums Research Conference in Scottsdale, AZ in December, 2014. It also has been presented to the Vidalia Onion Growers at their annual spring field day. And finally, the information on transmission Pantoea spp. by thrips has been published in a peer review journal (Phytopathology 104:812-819). Oregon (S. Reitz, C. Shock, E. Feibert, and M. Saunders) – The Oregon 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, workshops, 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 9, 2014 and August 26, 2014, an irrigation workshops on December 18, 2014, a pesticide short course, grower meetings on February 4, 2014, internet web sites (cropinfo.net), and results being reported in Onion World and other industry publications, such as the Capital Press. Pennsylvania (B. Gugino) – In Pennsylvania the research results were disseminated at several vegetable grower meetings/conferences including the Lancaster Onion Co-op meeting. On a national level, results were presented at the 2014 National American Phytopathological Society Meeting in Minneapolis, MN as part of a symposium titled “A Systems Approach for Microbe Management: From Food Safety to Plant Health” as well as a poster titled “Visual rating of bacterial disease severity as a threshold to time sweet onion harvest. In addition, Ph.D. candidate Emily E. Pfeufer, presented this research at Ohio State as part of the graduate student seminar exchange program. Results were also disseminated throughout the season through one-on-one with the growers collaborating in the intensive field survey project. We continued to disseminate the Diagnostic Pocket Series as well as the Onion Health Management and Production bulletin to interested growers and other stakeholders. Utah (D. Alston, D. Drost and C. Nischwitz) – Utah onion growers participated with Utah State University researchers and allowed them to survey 31 field sites (12 grower farms) in the Davis, Weber, and Box Elder County production onion areas in 2014. Fields were evaluated from early June through September for thrips, other insects, IYSV, plant growth and productivity. Variety research provided to and discussed with Utah growers (48 attendees) at the February 2014 winter onion meetings. USU research on weeds, crop rotations, crop nutrition, and IYSV provided to local growers as well (see presentations list below). Growers (38) attending the summer onion field tour (Aug 2014) learned about sustainable onion production, farm-scale thrips sampling and weed hosts, crop rotations and pest management, and onion varieties. Utah Onion Association board met twice (Apr, Nov) where they were provided with national updates on a variety of activities as well as information specifically needed by the local industry. Drost was an invited speaker at the NOA’s summer meetings where he outlined research and outreach efforts going on in Utah and how these can be applied to other production areas in the US. Details of Utah’s research presented in talks (Nischwitz) or poster (Drost et al) at the Dec NOA/NARC meetings in Phoenix, AZ. Washington (H. R. Pappu, T. Waters, C. Wohleb, and L. J. du Toit) - An onion pink root trial was completed near Connell, WA in a certified organic onion bulb crop to evaluate the potential for Serenade Soil to reduce the impact of this disease. The trial was carried out in both the south half and the north half of the field (repeats of the trial). The north half of the field had been rotated out of onions for only 2 years, and the south half for 4 years. As a result, pink root was much more severe in the north half of the field (average 66% of the roots with pink root symptoms/bulb) compared to the south half (an average 42% of the roots had pink root symptoms/bulb). A single application (banded over the bed) of Serenade Soil at planting at 4 qt/acre, or three applications at 2 qt/acre (at planting, 3 weeks and 6 weeks after planting) using a CO2-pressurized backpack sprayer, followed by 3-4 applications of water with the same applicator to incorporate the product into the soil, did not affect severity of pink root compared to the control plots. The results were similar for a trial completed in 2013 near Pasco, WA in a conventional onion bulb crop using this trial protocol. The trials indicate Serenade Soil may not reduce the impact of pink root in onion bulb crops, at least if applied as done in these trials. Symbiotic arbuscular mycorrhizal fungi (AMF) colonize roots of many plant species and help the plants mine soils for immobile nutrients, particularly phosphorus (P). AMF can also help defend plants against some root pathogens. Onions depend significantly on AMF since the symbiotic association compensates for the relatively sparse, unbranched roots with few root hairs. However, widespread use of soil fumigation and high rates of P fertilizer applications in onion crops in the Columbia Basin may negate or reduce significantly this symbiotic association with AMF. The inoculation protocol will need to be modified to facilitate detection of potential suppressive effects of AMF on pink root. Onion fungicide seed treatments commonly used in conventional onion crops in the Basin (Apron + Thiram, Farmore D300, and Farmore I500) all negated the beneficial effect of AMF on onion growth in growth chamber trials (including the repeated trial). However, soil application of the fungicide Quadris was either partially inhibitory (in one trial) or not inhibitory to AMF (in the repeat trial), and soil application of the fungicide Fontelis did not inhibit AMF (in either trial). These results have important ramifications for growers who routinely use fungicide seed and/or soil treatments for control of soilborne onion diseases. Attempts to evaluate AMF products in 3 grower-cooperator field trials in 2014 were complicated by incompatibility issues with product formulations and growers’ planting equipment. One or two AMF products were evaluated in each of three growers’ fields, but difficulties with application did not result in a reasonable evaluation of the potential value of these AMF inoculants in onion bulb crops. Additional research is needed to address these issues in order to obtain effective, robust evaluation of the potential value and cost-benefit of onion growers in the Columbia Basin using AMF products.