WERA_OLD66: Integrated Management of Russian Wheat Aphid and Other Cereal Arthropod Pests

(Multistate Research Coordinating Committee and Information Exchange Group)

Status: Inactive/Terminating

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SAES-422 Reports

Annual/Termination Reports:

[06/24/2008] [05/08/2009] [12/10/2010]

Date of Annual Report: 06/24/2008

Report Information

Annual Meeting Dates: 02/13/2008 - 02/13/2008
Period the Report Covers: 10/01/2006 - 09/01/2007

Participants

Cheryl Baker, USDA - ARS, Stillwater, OK
Do Mornhinweg, USDA - ARS, Stillwater, OK
Frank Peairs, Colorado State University
Gary Hein, University of Nebraska
Gary Puterka, USDA-ARS, Stillwater
Jack C. McCarty, USDA-ARS
John Burd, USDA - ARS, Stillwater, OK
John Reese, Kansas State University
Johnnie N. Jenkins, USDA-ARS
Kirk Anderson, North Dakota State University
Louis Hesler, USDA-ARS, Brookings, SD
Phil Sloderbeck Kansas State University Garden City
Tom Royer, Oklahoma State University
W. Rodney Cooper, Oklahoma State University

Brief Summary of Minutes

February 13, 2008

The 2007 WERA-066 meeting was held in conjunction with the International Plant Resistance to Insects conference (February 10-13) at the Hilton Ft. Collins (See attached agenda). Therefore, the annual meeting consisted of a brief business meeting that was scheduled from 1:00-4:00 pm, February 13, 2008. Chair Phil Sloderbeck, called the meeting to order at 1:00 pm and began the meeting with a round of introductions by those in attendance. Phil then introduced administrative co-advisor Tom Holtzer to address the group.

Tom Holtzer, Colorado State University, Administrative Advisor, provided a charge for the group and encouraged all to enroll into the NIMSS system http://www.lgu.umd.edu/lgumanual/toc.html.
This meeting worked well as a partner meeting with IPRI meeting. Accountability is important, shows accomplishments and impacts of research and educational programs. John Reese led discussion about developing collaborations with IPRI as Gary Thompson discussed.

1:15 PM State Reports -- Verbal reports were given by representatives from each state (Name in Parentheses) summarizing their written reports of recent insect activity and research results:

Colorado (Frank Peairs): Discussed the importance of spiders in system. Need for RWA-1 and RWA-2 resistant differentials to evaluate RWA biotypes.

Kansas (John Reese) Evaluating resistance to RWA-2 in wheat and barley. Looking at soybean aphid resistance

Nebraska- (Gary Hein) Barley, relationships to barley natural enemies. Areawide project in winter wheat completed. RWA research that is being conducted by Tiffany Heng-Moss is looking at gene expression profiling. Cereal arthropod research includes wheat curl mite, characterizing genetic diversity, virus transmission and mite movement potential. RWA populations were down from a year ago but other cereal aphids were present. BCO, English grain aphids, Greenbug. Barley Yellow Dwarf Virus were more prevalent than usual.

North Dakota (Kirk Anderson for Marion Harris) 2007 IPM Survey. 1000 wheat fields in 53 counties, for diseases and insects. Grasshopper populations were low, wheat stem maggot numbers are higher. Hessian fly: an independent survey showed that it is at an economic level in some fields. Orange wheat blossom midge survey: the trend is lower levels of wheat midge, but a few areas had treatable numbers.

Oklahoma ARS (Do Mornhinweg) Released 7 winter barley resistant lines. Many spring barley resistant lines for RWA. Are developing (developed) a seedling screen for BCOA. (Cheryl Baker): Resistance lines for RWA1 and RWA1 are being identified. (Gary Purterka) Collaborative agreement with Dr. Dillwith, looking at salivary gland constituents.

Oklahoma (Tom Royer) Hessian fly is prevalent, we are finding some wheat stem maggot in our plots, and dont know what impact that would have for this spring. We are validating the Glance n Go sampling system for greenbugs in Kansas, Oklahoma and Texas with growers (8 per state).

South Dakota (Louis Hesler) BCOA fall with BYDV. High populations in spring, mostly English Grain Aphid, some BCOA and greenbug. Looking for HPR for BCOA, found some in triticale, but breeders are not interested in crossing.

Following reports, discussion was initiated to determine the location and date of the next meeting. After a discussion with Dr. Holtzer about the time span needed for each meeting, the group agreed to explore the possibility of holding the meeting on September 22 or September 29, 2009 in Ardmore, OK, or Stillwater, OK. John Burd will make contacts with personnel at the Noble Research Center to see if they would host this meeting.

The next item of business was to identify the next secretary for WERA-66. Christie Williams, Purdue University, was identified by the nominations committee as a willing candidate, so Do Mornhinweg moved that she be nominated, seconded by Frank Peairs, and passed unanimously. Meeting was adjourned at 4:00 pm.

Minutes Attachment:

Attachment

Accomplishments

(Selected brief statements from State Reports. Full State Reports are in the file attached under Summary of Minutes.) COLORADO Pitfall traps have been established at three cropping systems sites. Spiders are being collected and identified. A manuscript on carabid results is in press. Uniform aphid natural enemy observations are taken at all three locations Russian wheat aphid biotype 1-resistant wheat cultivars are now planted on more than 25% of Colorados wheat acreage. The level of use has remained constant even though RWA-1 seems to have been largely replaced by RWA-2. Winter wheat lines with the 2414-11 resistance source continue to be advanced. Two will be evaluated for yield loss to Biotype 2 in the spring of 2008. Resistant feed barley varieties were tested on-farm in 2006 and 2007. Stoneham and Sidney are resistant to known RWA biotypes and performed better than Otis, their recurrent parent, under very dry conditions and in the presence of Russian wheat aphid. Surveys were conducted to determine the presence of Dn4-virulent Russian wheat aphids. Russian wheat aphid was scarce in 2007, but the percentage of samples containing Dn-4 virulent aphids has continued to increase since the initial survey in 2004 (96% in 2007). No virulence to 2414-11 was detected. An additional 2300 lines from the national wheat germplasm collection, 600 other breeding lines and 4500 individual progeny were screened for resistance to Biotype 2. Additional potential resistance sources were identified for bothRWA-1 and RWA-2. Dryland cropping systems studies are ongoing at three locations in eastern Colorado. Stoneham, a RWA-resistant feed barley, has been added to some rotations. Generally, rotations have been modified to incorporate more forages, and sunflower has been eliminated. Aphid flights were monitored at four locations by means of suction traps. For the first time, zero Russian wheat aphids were collected in the Akron trap, and only one was collected from the Briggsdale trap. Nine foliar insecticide treatments were compared to commercial standard insecticide treatments for control of Russian wheat aphid in winter wheat. Cobalt (chlorpyrifos + gamma cyhalothrin) was similar in performance to the standard chlorpyrifos treatment, which currently is the product of choice for Colorado wheat producers. Methomyl was compared to chlorpyrifos and several pyrethroids for control of Russian wheat aphid in spring barley. Two applications of methomyl performed nearly as well as the chlorpyrifos treatment, providing barley producers with another potential control option. INDIANA Insect feeding disrupted by wheat lectin. Production of the HFR-1 wheat lectin is triggered by avirulent Hessian fly larvae. Because these larvae are obligate parasites and cannot be cultured in vitro, the effect of this lectin was tested on Drosophila melanogaster larvae as they consumed an artificial diet. At low to intermediate concentrations, this lectin prolonged larval development. But at high concentrations it deterred feeding and repelled the larvae, causing them to leave the diet medium and reside on the sides of the glass vial until death, 4 days later. This lectin may be useful as a feeding deterrent in transgenic plants. Amino acid content of susceptible plants is manipulated by virulent Hessian fly larvae. Virulent Hessian fly larvae alter the production of certain amino acids in their host wheat plants. Essential amino acids that the larvae must obtain from their diet increase in abundance in susceptible wheat. This includes methionine, histidine and phenylalanine. The increased production of phenylalanine and tyrosine by the host wheat plant may be important for cuticle production in the immature insects. Molecular interaction between Hessian fly and wheat Previous research directed toward transcriptional profiling of genes expressed in Hessian fly larvae during interactions with wheat has revealed the following: 1. On susceptible plants genes involved in establishing a sustained feeding site, manipulation of host-plant cells, feeding and growth/development are up-regulated; 2. On resistant plants genes involved in responding to stress and disruption of homeostasis (DAD defender against apoptotic cell death, heat shock, detoxification, antioxidant defense, excretion, etc) are up-regulated; 3. On resistant plants larvae encounter toxic plant compounds, feeding deterrents, or cannot manipulate host-plant cells to develop a nutritive tissue. Current research is focused toward: 1. RNAi as a function genomics tool for genes expressed during Hessian fly/wheat interactions; 2. comparative salivary gland transcriptomics; 3. electron microscopy studies of the larval midgut during compatible and incompatible interactions with wheat. Progress toward understanding Hessian fly biotypes. A bacterial artificial chromosome (BAC) based physical genetic map has been constructed of the Hessian fly genome. This map consists of 270 BAC fingerprint derived contigs (FPC) positioned in the genome by fluorescence in situ hybridization (FISH). The ends of the BACs in these contigs have been end-sequenced and an additional 100 simple sequence repeat (SSR) markers have been identified on BACs in the map. The BACs and the contigs can be identified using Hessian fly Web FPC: http://genome.purdue.edu/WebAGCoL/Hfly/WebFPC/. Three genes that determine the biotype status of Hessian fly larvae have been positioned on the physical genetic map. These genes determine the ability of the larvae to survive and stunt wheat carrying the specific resistance genes H6, H9, and H13. Generally referred to as Avriulence (Avr) genes, they have been named according to their corresponding resistance gene as vH6, vH9, and vH13. vH6 has been positioned between two adjacent contigs on the long arm of Hessian fly chromosome X2. Three genetic map units separate the contigs. vH9 has been positioned within a single contig on the short arm of Hessian fly chromosome X1. vH13 has been positioned within a single BAC clone within a contig on the short arm of Hessian fly chromosome X2. Results clearly indicate that Hessian fly virulence and avirulence to specific resistance genes in wheat results from mutations in single genes. Thus, the wheat-Hessian fly interaction clearly appears to have a gene-for-gene basis. KANSAS Comparisons of Wheat and Barley Resistance to Russian Wheat Aphid Biotype 2. This research project reports the categories of resistance (antibiosis, antixenosis, tolerance) to Russian wheat aphid, Diuraphis noxia (Kurdjumov), biotype 2 present in a cereal introduction Triticeae (CItr) 2401, and a barley breeding line (IBRWAGP04-7), when compared to control resistant and susceptible wheat and barley genotypes. CItr2401 and IBRWAGP04-7 exhibit no antixenosis to D. noxia biotype 2, but both lines demonstrate antibiosis to D. noxia in the form of reduced aphid populations in comparison to susceptible controls. Leaf and root dry weight changes exhibited by infested CItr2401 and IBRWAGP04-7 plants were significantly less than those of infested plants of the susceptible control varieties. However, when a tolerance index was calculated to correct for differences in aphid populations, these differences in D. noxia tolerance to were negated. Categories of Resistance to the Russian Wheat Aphid Biotype 2 Operating in Parents of Aphid-Resistant CIMMYT Synthetic Wheat Lines. To identify and characterize sources of North American to D. noxia biotype 2 resistance, synthetic hexaploid wheat lines created at the International Maize and Wheat Improvement Center (CIMMYT) were evaluated for potential resistance. Several CIMMYT genotypes and their parents were resistant to aphid induced - leaf rolling and chlorosis, and sustained significantly less damage than plants of the susceptible control Jagger. In general, fewer biotype 2 aphids were produced on genotypes with reduced chlorosis and leaf rolling, and aphid numbers were highly correlated with chlorosis and with leaf rolling. However, large biotype 2 populations developed on the parent line Ae. tauschii 518, although this genotype was highly resistant to leaf rolling and chlorosis. These biotype 2 resistant lines, which are also resistant to D. noxia populations in Mexico and to greenbug, Schizaphis graminum Rondani, biotype G, are strong candidates for use in improving the genetic diversity in bread wheat for resistance to different biotypes of both S. graminum and D. noxia. Categories of Resistance to Russian Wheat Aphid Biotype 2 in Bread Wheat Genotypes. Diuraphis noxia North American biotype 2 is virulent to the D. noxia resistance genes Dn1, Dn2, Dn4, Dn5 and Dn6. Thus, a need exists for an improved understanding of the categories of resistance in all sources of biotype 2 resistance. In this study, wheat genotypes containing the resistance genes Dn4, Dn6, Dn7, Dnx, and a susceptible control (Dn0) were infested with D. noxia biotype 2 to determine the extent of the antibiosis and tolerance categories of resistance operating in each genotype. All infested resistant genotypes expressed some chlorosis and leaf rolling. Tolerance indices (TI) for shoots, roots and plant height of Dn6 were significantly lower (more tolerant) than those of Dn0. Plant height TI of Dnx plants was also significantly less than that of Dn0. Thus, both Dn6 and Dnx plants are tolerant to D. noxia biotype 2 infestation. Both Dn7 and Dnx plants exert antibiosis effects and significantly reduce D. noxia populations compared to Dn0. Despite the strong resistance of the Dn7 genotype from rye, Dn7 has deleterious effects on bread wheat baking quality. Dnx, from bread wheat, carries no negative quality traits and offers a suitable genotype for ready adaptation into Kansas wheat cultivars. Interactions Among Biological Control, Cultural Control and Barley Resistance to the Russian Wheat Aphid in Colorado, Kansas and Nebraska. This research is being conducted to determine the interaction among biological control, cultural control and barley resistance to the Russian wheat aphid resistance in fields located in Colorado, Kansas, and Nebraska. The experimental design is a split-plot design with two main plot treatments (early, and delayed planting dates). Within each main treatment plot, four split-plot treatments (varieties) are randomized. In 2007, these treatments included two new D. noxia biotype 1 and 2 resistant barley cultivars, Stoneham and Sydney, and the susceptible cultivar Otis under triamethoxam-protected and unprotected regimes. Aphid, natural enemy and incidence sampling was conducted at four dates from late May through early July in 2007. Differences in the mean number of aphids were detected by location and variety during the second sampling, when unprotected Otis plants contained the highest numbers of aphids in Colorado and Kansas. On the third sampling date, unprotected Otis plants in Nebraska contained the highest numbers of aphids. There were complex interactions between the natural enemies observed in the three fields and these are being subjected to further analyses. NEBRASKA Demonstration Trials of New Resistant Barely Varieties This project was done cooperatively with Frank Peairs (CSU) to test the new RWA resistant barley varieties (Sidney, Stoneham) in larger strip trials in various environments for yield and aphid response. Through the Nebraska panhandle and Colorado we had twelve trial sites out. The four sites in Nebraska varied a great deal due to moisture stress. Two of the locations had severe stress were not carried to harvest. The other two locations had moderate yields. Growers were pleased with the performance of the barley and remain interested in growing resistant barley; however drought conditions over the last several years have reduced the interest level in all spring/summer crop alternatives. Improved Management of Russian Wheat Aphid in Barley by Integration of Biological-Cultural Controls with Aphid-Resistant Cultivars The research objective of the project is to determine the cost and benefits of two new RWA resistant barley varieties (Stoneham and Sidney) compared to existing production varieties and aphid management strategies. We also have an educational component to the project with the objective to develop educational programming to promote the adoption of RWA-resistant barley and appropriate biologically intensive pest management practices as viable components of diversified cropping systems in the western High Plains. Data collection from the first growing season was completed with barley yields at Sidney in the mid 30s (bu/A). Biology of the Wheat Curl Mite and its Relation to the Epidemiology of Wheat Streak Mosaic Virus A significant effort is underway to determine the biological and ecological factors that are important to the management of the wheat curl mite and its vectored viruses, wheat streak mosaic virus and high plains virus. The major objectives of this work include: 1) Characterization and identification of the wheat curl mite biotypes. 2) Predicting wheat curl mite movement and wheat streak mosaic virus spread. 3) Using wheat curl mite populations for screening wheat lines for resistance to wheat streak mosaic virus. This project has resulted in testing and verification of the high level of virus resistance in a soon to be released variety, Mace. NORTH DAKOTA 2007 IPM Survey Maps from the 2007 IPM survey in North Dakota were uploaded onto the NDSU IPM website at the following address: (http://www.ag.ndsu.nodak.edu/aginfo/ndipm/) A state-wide survey of small grain diseases and insects continued during the 2007 growing season. Types of insects monitored include: aphids (species not distinguished), grasshoppers, wheat stem maggot and cereal leaf beetle. A total of 1,100 wheat fields were surveyed covering all 53 counties of ND during 2007. This approximately represents one field surveyed per 6,700 acres of wheat. The survey was initiated on May 29 and continued through August 9, 2007. Crops were surveyed from the 1-leaf stage through hard kernel (ripening) stage. Field scouts surveyed for insect pests of winter wheat, hard red spring wheat, and durum wheat. All other judgments of pest problems encountered in 2007 are based on reports from County Extension Agents and farmers. Background on North Dakota Survey for Diseases and Pests For the last ten field seasons, aphid monitoring has been carried out as part of a larger effort to survey diseases and insect pests in North Dakota cereals. The state is covered by 5-6 scouts who monitor fields within a county every 1-2 weeks from May through August. The insects that are monitored in cereals include: aphids, grasshoppers, and cereal leaf beetle. Results of these surveys can be found at: www.ag.ndsu.nodak.edu/aginfo/ndipm/05IPMSur/HTML/WheatIPMsurvey.htm. Background on North Dakota Autumn Survey for Wheat Midge In the mid 1980s, a major wheat midge outbreak began in northern Canada and subsequently spread in the 1990s to large areas of Manitoba, Saskatchewan, North Dakota, and northwestern Minnesota. Although wheat midge numbers have declined in recent years the North Dakota Wheat Commission is still concerned enough about wheat midge to pay for an annual soil survey that provides estimates of overwintering wheat midge populations. For this survey county agents send in soil samples in September and October from the current years wheat fields. In our lab, we examine these soil samples for wheat midge cocoons. Cocoons contain overwintering third instar larvae. When wheat midge cocoons are found, larvae are dissected to estimate parasitism levels. A map of wheat midge larval numbers, which takes into account expected mortality from parasitism, is made available to wheat farmers in February/March each year. OKLAHOMA Overview of Current Research and Accomplishments Barley Breeding Program RWA-resistant, 6-rowed, spring malting barley germplasm lines STARS 0601B - STARS 0619B, 2-rowed spring malting barley germplasm lines STARS 0620B - STARS 0636B, and 2-rowed spring feed barley germplasm lines STARS 0637B- STARS 0643B were released. These lines were developed by backcrossing 31 different sources of resistance into spring barley cultivars of each barley type, 6- rowed malt, 2-rowed malt, and 2-rowed feed. These lines were developed by USDA-ARS in Stillwater, and evaluated and selected in Idaho, Colorado and/or Nebraska with assistance of. Phil Bregitzer, USDA-ARS, Aberdeen, ID, Frank Piears, Colorado State University, and Gary Hein, University of Nebraska. Increases have been made prior to release of 10, RWA-resistant, 6-rowed, winter, feed barley germplasm lines resistant to both Greenbug and RWA. Barley cultivar was released by USDA-ARS in 2007. This cultivar was developed by USDA-ARS, Stillwater, OK and selected and evaluated by USDA-ARS, Aberdeen, ID. The main component of resistance in RWA 1758 is tolerance and is derived from STARS 9577B. A breeding program has been initiated to develop winter, hulless, feed barleys resistant to both RWA and Greenbug, adapted to Oklahoma, and suitable for ethanol production. Hulless winter barleys, selected for adaptation to OK as well as percent starch, were crossed as males to RWA and greenbug resistant lines developed by USDA-ARS in Stillwater. Evaluation of female parents is ongoing as well as crossing and backcrossing of hulless lines to selected females. 615 F2 head rows were grown in Woodward, OK in the summer of 2007. Thousands of heads were selected and hulless heads were screened to RWA and greenbug in the fall of 2007. Resistant segregates will be increased in the greenhouse in the spring of 2008. 104 hulless F3 bulks were planted in Woodward in the fall of 2008. A seedling screening test for BCOA resistance has been developed and tested for repeatability. Two replications of the Barley Core Collection (960 accessions) were screened with this new technique in the summer of 2006. Survivors were grown in pots in the greenhouse and data collected for plant height, grain yield, and yield components. Five seed each of 364 survivors were screened with BCOA in the summer of 2007. An aphid free set of identical flats was also grown. Selected survivors from the screening were rescued and, along with their matching non-infested checks, transplanted into pots in the greenhouse. Infested and non-infested pots for each line were placed side by side on greenhouse benches for increase. Plant height, grain yield, and yield components will be measured. Wheat Breeding Program Included in the guidelines in the WERA 2006 report were recommendations for establishing set plant differentials for use as screening tools, thereby eliminating one of the obvious sources of variability in our screening techniques. In order to standardize the seed source for researchers, it was determined that these plant differentials would be available to RWA researchers via Stillwater USDA-ARS, as sufficient seed is available. Seed is now available for small screening tests, and if larger amounts of seed are required for an individual program, then starter seed can be obtained from Stillwater, and seed can then be increased as needed at the various locations. In order to establish this uniform set of differentials, the suggested differential lines were screened for homogeneity for RWA1 resistance, and plants were then grown and harvested with an eye for uniform maturity, height, and other observable characteristics. Off-types were discarded. Progeny screening is being done prior to further increases. We have continued with the development of our breeding lines that are resistant to RWA1. Even though they may not be useful as germplasm or variety releases in the near future with the current prevalence of RWA2, different sources of RWA1 resistance that are due to different genes may provide additional differentials for screening against new RWA biotypes that may develop. In addition, several possible differentials resistant to RWA2, yet susceptible to RWA1, have been identified and increased. The screening of current breeding lines for resistance to RWA2 is also underway, as space and conditions allow. Several of our winter breeding lines containing Dn7 appear to be resistant to all RWA biotypes against which they have been tested. Our germplasm release STARS-0601 has also been resistant to all RWA biotypes against which it has been tested. Sorghum Breeding Program Greenbug is an important insect pest, limiting crop production throughout the world. Since 1968, the greenbug has become the predominant pest of sorghum in the Great Plains. A few sources of sorghum germplasm were identified as resistance to greenbugs at various times; however new and virulent biotypes have been able to overcome most existing sources of genetic resistance. In order to exploit new sources of greenbug resistance, we initiated a project toward a systematic evaluation of the entire U.S. collection of sorghum germplasm (over 40,000 accessions). Now screening sorghum germplasm against greenbug biotype I has been done, and the evaluation results indicate that more than 40 germplasm accessions have some degrees of resistance to greenbug biotype I. These sources of greenbug resistance in sorghum germplasm, particularly those newly identified resistant lines, should be valuable for the development of new greenbug-resistant sorghum cultivars or hybrids. Host-plant resistance has been used in many sorghum breeding programs for controlling the pest in the past. Molecular tools such as DNA markers can be used to identify and monitor the genetic components responsible for pest resistance, facilitating the breeding process. We have recently constructed a genetic linkage map for sorghum using SSR markers. With this genetic map, we have been able to identify several DNA (SSR) markers closely associated with a major QTL which conditions resistance to the greenbug. These DNA markers proved a useful tool for marker-assisted selection. The major QTL detected in this study and the tightly linked SSR markers will facilitate efficient development of resistant lines or hybrids in sorghum. RWA Biotype Diversity and Ecology Studies have been ongoing since 2006 on the ecology of overwintering RWA in diverse environments to determine if and how sexual reproduction (holocycle) occurs and its role in biotype development. This research is further supported by studying the effects of photoperiod, temperature and host on sexual form induction in the laboratory. In 2007, This research was further expanded to include the overwintering ecology of three other Diuraphis spp. endemic to the U.S.A., D. tritici, D. nodulus, and D. frequens. These species are known to go sexual in the fall and serve as positive controls in field and lab studies. Data is still being collected and conclusions not yet firm. However, it is obvious that D. noxia does not respond to environmental stimuli in the same manner as the three other Diuraphis spp. A study was conducted in collaboration with Frank Peairs and Terri Randolph to determine if there was a uniform response of RWA biotypes RWA1 RWA7 to 24 plant differentials under differing environmental conditions and locations. This study concluded that results were uniform between locations and researchers that used the same seed sources and RWA biotype sources. Future plans are to arrange collaborations with State researchers to sample sites for monitoring RWA biotypic diversity. Molecular Ecology of Cereal Aphids and their Natural Enemies To date, all results support the hypothesis that RWA was introduced once into North America, and the path of the introduction was from South Africa to Mexico, then a natural spreading of populations north into the US. The occurrence of biotypes in 2003 came after planting of Dn4 resistant wheat varieties, which began in about 1996. All data supports the hypothesis that Dn4 virulent biotypes were not introduced, but arose from the extant population. Although RWA in the US lacks genetic variation (measured by various molecular markers), it is phenotypically diverse, i.e. shows variation in its ability to injure hosts with and without plant resistant genes. Predicting the impact of predators and parasites In conjunction with collaborators from Oklahoma State University we continued research to develop a predictive population dynamics model for the greenbug. We are in the third year of a field study to quantify the spatially explicit population dynamics of the greenbug in relation to parasitism by L. testaceipes and predation by Coccinellidae and other predators. The research has potential to improve pest management practices for the greenbug in wheat. If successful, treatment decisions will be more accurate and based on improved knowledge of the potential for biological control. Remote sensing of cereal aphids In conjunction with collaborators from the Texas Agricultural Experiment Station and TerraVerde Technologies we are developing remote sensing technology to detect and monitor Russian wheat aphid infestations in winter wheat. During the previous year we documented that multi-spectral remote sensing differentiated stressed areas in production winter wheat fields caused by the Russian wheat aphid from non-stressed areas. We also documented that it is possible to differentiate stressed areas in wheat fields caused by Russian wheat aphids from areas stressed by other factors based on spatial pattern analysis and multivariate discriminant function analysis (see figure in attached file). The technology could improve pest management practices for the Russian wheat aphid in winter wheat because infestations in fields will be efficiently detected and delineated before treatment is required. SOUTH DAKOTA Overview of Cereal-Aphid Research Activities and Accomplishments: Rhopalosiphum padi (L.) (bird cherry-oat aphid) and Diuraphis noxia (Kurdjumov) (Russian wheat aphid) are common aphid pests of wheat and can co-occur at relatively high levels within wheat fields. Resistance to both aphids has been identified in several triticale accessions. We conducted experiments to identify and characterize antibiosis-type resistance to R. padi in additional triticale lines and to test R. padi-resistance levels in several backcrossed, triticale-derived lines of D. noxia-resistant wheat. Triticale accessions 6A-558, H85-734 and M86-6174 were identified with moderate levels of antibiosis to R. padi. All three accessions limited R. padi population growth relative to Arapahoe over 13 d. 6A-558 increased development time of R. padi compared to that on Arapahoe, and 6A-558, H85-734 and M86-6174 each decreased the number of nymphs produced by R. padi over 7 d. Additional tests confirmed N1185 triticale as a strong source of resistance to R. padi, and showed that Lamar wheat was not resistant to R. padi. Tests of wheat lines derived from crosses between N1185 and Lamar and then selected for resistance to D. noxia showed that three of 13 lines reduced the number of R. padi per plant, with resistance levels comparable to N1185 in two lines. Nymphiposition by R. padi measured over a 24-h period did not differ among any lines in no-choice tests. The results provide further support that triticale is a significant source of resistance to R. padi, but further work is needed to understand transference of R. padi-resistance from triticale to wheat. TEXAS Map-based cloning of greenbug resistance gene Gb3 in wheat This project aims to clone the Aegilops tauschii-derived greenbug resistance gene Gb3 from wheat (Largo source). Previously Gb3 was placed in the distal bin of wheat chromosome arm 7DL with several Gb3-linked microsatellite markers. We are conducting fine genetic and physical mapping of Gb3. Three complementary populations at diploid and hexaploid levels were used for high-resolution genetic mapping with SSRs, EST-, RFLP- or AFLP-derived STS markers. So far, 31 markers have been placed on the genetic map surrounding the Gb3 locus and a 2.0 cM interval of Gb3 is delimited by one AFLP-STS and one EST-STS marker. More markers are being developed by exploring the rice and Brachypodium distachyon whole genome sequences. Screening of an Ae. tauschii BAC library is also underway to initiate chromosome walking. Marker-assisted selection and development of greenbug-resistant wheat cultivars In the Texas Wheat Breeding Program, we are actively implementing the marker-assisted selection (MAS) strategy to expedite the breeding process. Priority traits for MAS include resistance to the greenbug, Russian wheat aphid, wheat streak mosaic virus and the wheat 1AL.1RS translocation. As a test case, one rye 1RS-specific marker and two Gb3-linked molecular markers are being used to screen large breeding populations. These markers seem to be highly predictable in selecting plants carrying the target genes. The wheat cultivar, TAM 112 carrying the greenbug resistance gene Gb3 and 1AL.1RS wheat-rye translocation is gaining increasing acreages in the Southern Plains since its release by the Wheat Improvement Program of Texas AgriLife Research at Amarillo in 2005. Molecular mapping of greenbug resistance genes in wheat and barley Molecular markers are being developed for the greenbug resistance genes Gb2, Gb6 in wheat, and Rsg1, Rsg2 in barley. These markers will be used in marker-assisted selection and development of wheat/barley germplasm with multiple resistances. Gb3-mediated host defense responses against greenbug feeding in wheat In a 2-genotype (bulked segregant R and S super pools), 3-time-point (0, 24 and 48 hours after infestation, hai), 3-replicate experiment, 18 Affymetrix GeneChips were used to investigate Gb3-mediated defense responses upon greenbug feeding. Of the ~61,000 transcripts surveyed, 47 showed significant differences in constitutive expression between the R and S pools (p = 0.05). Nearly 10,000 probe sets exhibited significant changes in expression level in both genotypes at 24hai and/or 48 hai, among which about 6,000 have putative functions. Of the 6,000 transcripts, 706 showed significantly altered expression in the R pool as compared with those in the S pool at either 24hai or 48hai or both. Analysis of expression patterns of the 706 probe sets suggested that Gb3-mediated host defense responses in wheat to greenbug feeding are more similar o plant pathogen attacks, but wounding responses are also obvious. Development of molecular markers in the greenbug The abundance and distribution of simple sequence repeats (SSRs) were explored in the EST and genomic sequences of the pea aphid and the green peach aphid. A total of 1112 newly developed, together with 40 published SSR markers were investigated for their cross-species transferability among 6 aphid species. Genetic diversity among 24 greenbug biotypes was further examined with 30 transferable SSRs. It was found that the pea aphid genome is abundant in SSRs with unique frequency and distribution of SSR motifs. Cross-species transferability of EST-derived SSRs is dependent upon phylogenetic closeness between SSR donor and target species, but is higher than that of genomic SSRs. Neighbor joining analysis of SSR data revealed host-adapted genetic divergence as well as regional differentiation of greenbug biotypes.

Publications

Please see attached file.

Publications Attachment:

Attachment

Impact Statements

Improve knowledge of cereal arthropods among scientists, producers and other interested clientele. Develop new or improved management practices for cereal arthropods. Monitor for newly introduced pests or the development and Improve knowledge of cereal arthropods among scientists, producers and other interested clientele.
Develop new or improved management practices for cereal arthropods.
Monitor for newly introduced pests or the development and spread of new more damaging biotypes.

Date of Annual Report: 05/08/2009

Report Information

Annual Meeting Dates: 02/25/2009 - 02/25/2009
Period the Report Covers: 10/01/2007 - 09/01/2008

Participants

Phil Sloderbeck, Kansas State University;

Bryan Fontes, New Mexico State University;

Kirk Anderson, North Dakota State University;

Tom Royer, Oklahoma State University;

Ed Bynum Texas, Agrilife Extension;

Roxanne Fegley, Agrilife Extension;

Cheryl Baker, USDA-ARS Stillwater, Oklahoma;

Barbara Driskel, USDA-ARS Stillwater, Oklahoma;

Do Mornihnweg, USDA-ARS Stillwater, Oklahoma;

Gary Puterka, USDA-ARS Stillwater, Oklahoma;

Kevin Surfran, USDA-ARS Stillwater, Oklahoma;

Jim Webster, USDA-ARS Stillwater, Oklahoma;

Christie Williams, USDA-ARS West Lafayette, Indiana;

Vicki Tolmay, ARC-SGI Bethlehem, South Africa;

Tom Holtzer, Colorado State University

Brief Summary of Minutes

WERA 066 was held in conjunction with the joint meeting of the South West Branch of the Entomological Society of America and the Society of south West Entomologists, which ran from February 23-26 in Stillwater, OK. The session took place in the Wes Watkins Center, room 101, on the campus of Oklahoma State University.

1:30 pm Business Meeting
Chair Tom Royer called the meeting to order and began with a round of introductions by those in attendance. Tom then read the minutes of the 2008 meeting that was held in Ft. Collins, CO. Phil Sloderbeck moved that the minutes be approved and Do Mornhinweg seconded the motion, which then carried.

Tom Holtzer, the WERA 066 Administrative Advisor, informed the group that a mid-term review is due this year. The report will focus on outcomes and impacts of this group. This report will be prepared by Chair Tom Royer and Secretary Christie Williams.

1:55 pm Discussion and Oral Summaries of State Reports
North Dakota - Kirk Anderson
Several surveys were conducted during the past two years. The 2007 IPM Survey focused on grain aphids, grasshoppers, cereal leaf beetle, wheat stem maggot and barley thrips. The use of insecticide was a key factor in preserving the high quality of barley so that farmers could sell the crop for malting rather than as lower quality feed barley.

In addition, 2008 surveys were done for orange wheat blossom midge, wheat stem saw fly, plus other insects and diseases. The 2008 Hessian fly Survey characterized the utility of a five-component blend of sex-pheromones to determine geographic distribution, seasonal abundance and number of generations per year. Results indicated that the Hessian fly is distributed state-wide. Populations peaked in midsummer and again in September, indicating a lack of aestivation. The fall emergence occurred after the suggested wheat planting date (fly-free date).

A general discussion about Hessian fly followed. Researchers from several states reported using or having interest in using the Hessian fly pheromones to characterize populations. Phil Sloderbeck said that, similar to North Dakota, in Kansas Hessian fly flights were later in the fall than expected, after the fly-free date for planting wheat. Some years, such as 2008, wheat must be planted late due to weather conditions. At the Colorado-Kansas border Hessian fly populations seemed high, probably due to two factors: higher than normal rainfall in August causing sprouting of volunteer wheat that serves as insect refuge and continuous no-till wheat, without rotation or fallow, that allows survival. Hessian fly hadnt been seen in that region for over 20 years. Pyrethroids were effective in controlling Hessian fly. A new flyer on Hessian fly is on Phils web site http://www.oznet.ksu.edu/library/entml2/MF2866.pdf.

Kirk Anderson mentioned that in North Dakota some durum wheat cultivars that were never intentionally bred for Hessian fly-resistance are quite resistant. Similar observations were made in Oklahoma. Christie Williams notes that durum wheats have been a strong source of resistance genes that have been introgressed into common wheat in the Purdue breeding program (added to the minutes).

It was mentioned that the fly-free dates that were first promoted in the 1920s may not be accurate today. Hessian flies have been observed to fly even in cold weather. It was mentioned that a fall infestation of Hessian fly may not necessarily lead to high spring infestations or crop damage. This is believed to be because Hessian flies damage the tiller on which they reside and tillers that form later are normal unless a secondary infestation occurs. A short discussion on Hessian fly population movement followed. It was reported that an edge effect can be observed in a field if adjacent to a no-till field with high populations. But Kirk Anderson and Christie Williams mentioned that Hessian flies are not strong flyers so dont migrate far, but could be dispersed by wind. Marion Harris has a paper published on this topic.

Oklahoma Do Mornhinweg, Cheryl Baker and Gary Puterka
Fifty Russian Wheat Aphid-resistant barley lines have been released to date. In collaborative research QTL analysis identified two major and one minor locus contributing to resistance, and mapping of resistance genes is being pursued. Differentials for biotype 1 and 2 are being pursued. Studies are ongoing to monitor RWA biotype diversity throughout the US and identify zones where RWA may become holocyclic. Parasitoids of greenbug have been identified.

A general discussion followed, concerning whether different RWA biotypes were distinct introductions or whether the same biotypes spontaneously evolved in multiple locations.

Texas Roxanne Fegley and Ed Bynum
Greenbug infestations are now at levels that warrant treatment. Also, RWA and Hessian fly have been found in Texas. A study of perennial grasses offers an opportunity to monitor movement and virus vectoring of wheat curl mite.

Indiana Christie Williams
Several molecular studies are underway. The Shukle lab is characterizing genes encoding Hessian fly secreted salivary gland proteins, believed to be effectors that induce plant susceptibility as well as avirulence proteins that induce resistance. The sequence diversity of these genes is greater in Israeli populations than in the US. These Israeli genes may be ancestral types.

The Shukle and Williams labs have done a transmission electron microscopy study showing that midgut microvilli are disrupted in avirulent Hessian fly larvae feeding for just three hours on resistant wheat plants. After six hours of feeding the microvilli are absent. The microvilli do not deteriorate in virulent larvae and larvae starved on filter paper. Thus, the resistant wheat plant quickly responds and inflicts damage to avirulent larvae.

The Williams lab has identified several genes encoding lectins that may disrupt the Hessian fly larval midgut. These lectins target high-mannose glycoproteins that are believed to be common in insect midgut. Virulent Hessian fly larvae alter the physiology of their host plants, causing them to produce aminoacids and polyamines that are beneficial to the insects. In addition their data supports findings by the Harris lab that has shown that epidermal cells of susceptible plants degrade when under attack. Virulent larvae are able to cause loss of cutin in the cuticle of wheat leaves at feeding sites and suppress production of mRNA encoding lipid transfer genes. These changes are thought to lead to loss of cell integrity and general increase in permeability that delivers nutrients to the larvae.

The Stuart lab is using a map-based approach to locate Hessian fly genes that allow them to be virulent on wheat containing resistance genes H6, H9 and H13. These genes have been mapped to 80- to120-kb segments on chromosomes X1 and X2. Associative mapping with Hessian fly populations from five southeastern states identified diagnostic markers, visualized on agarose gels, for flies virulent to these genes and supports the gene-for-gene basis of interaction with wheat.

4:40 pm - Identification of Secretary and Location for Next Meeting
Gary Puterka was nominated by Do Mornhinweg he and accepted. The current secretary, Christie Williams will become the next chair. Kevin Surfran moved that Ft. Collins Co be the location of the 2010 WERA 066 meeting and Phil Sloderbeck seconded the motion, which then carried.

4: 48 pm - Adjournment
Phil Sloderbeck moved the meeting be adjourned and Do Mornhinweg seconded the motion, which then carried.

Minutes Attachment:

Attachment

Accomplishments

ACCOMPLISHMENTS HIGHLIGHTS (SEE ATTACHMENTS UNDER MINUTES FOR FULL STATE REPORTS) Colorado State University Plant Resistance 1. Winter wheat lines with the 2414-11 resistance source continue to be advanced. Lines with other sources are in earlier stages of development. 2 Surveys were conducted to determine the presence of Dn4-virulent Russian wheat aphids. Russian wheat aphid remained scarce in 2008, but the percentage of samples containing Dn-4 virulent aphids has continued to increase since the initial survey in 2004 (98% in 2008). No virulence to 2414-11 was detected. Biology and Management 1. Dryland cropping systems studies are ongoing at three locations in eastern Colorado. Stoneham, a RWA-resistant feed barley, has been added to some rotations. Generally, rotations have been modified to incorporate more forages, and sunflower has been eliminated. 2. High elevation noncultivated grass hosts were surveyed for a fifth season. Oversummering Russian wheat aphids appear to be widespread in noncultivated grasses at higher elevations, but their relationship to wheat production is unknown. +++++++++++++++++++ USDA-ARS Crop Production and Pest Control Research Unit, at Purdue University, West Lafayette, Indiana 1 Analyzing the diversity of secreted salivary gland transcripts in Hessian fly populations from Israel and the United States The salivary glands and midgut of the larval Hessian fly are the primary interfaces with wheat. Little is known about the roles of these two organs in the interactions between larval Hessian fly and wheat. However, secreted salivary gland proteins (SSGPs) in the larval Hessian fly are hypothesized to be the effectors reprogramming host-plant tissues in compatible interactions with susceptible wheat and to be the avirulence gene products eliciting resistance in incompatible interactions with resistant wheat. Initial comparison of the transcripts encoding SSGPs in populations of Hessian fly from Israel has revealed greater diversity than is present in populations from the United States. Some of these divergent SSGPs in Israeli populations fall basal in phylogenetic analyses to clades containing families of SSGPs, suggesting these divergent SSGPs may represent ancestral types. Through comparative analyses, bioinformatics, and functional analyses we seek to gain insight into the possible evolution of these SSGP effectors and their roles in the interactions between larval Hessian fly and wheat. 2 Ultrastructural changes in the midgut of Hessian fly larvae feeding on resistant wheat The Hessian fly is present in all the wheat producing regions of the United States and is the most important insect pest in the southeastern soft-winter-wheat region. Genotypes of the pest that can overcome formerly resistant wheat continue to appear and pose a threat to wheat production. There is a need to better understand the mechanisms by which resistant plants are able to prevail over larval attack. The midgut is one of the major interfaces between the larval Hessian fly and its host plant. The goal of the present study was to determine if ultrastructural changes occur in the midguts of larvae feeding on resistant wheat compared to larvae feeding on susceptible wheat and larvae experiencing starvation while removed from the plant. Results have revealed that within three hours of initiating feeding on resistant wheat midgut microvilli were disrupted and after six hours microvilli were absent. These microvilli disruptions observed in Hessian fly larvae feeding on resistant wheat were similar to those occurring in midgut microvilli of Drosophila larvae fed on a diet containing 1% wheat germ agglutinin. These results suggest the midgut is a major target of toxic plant compounds such as lectins that may play a pivotal role in resistance. 3. Characterization of wheat plant processes manipulated by Hessian fly larvae Interactions of first-instar Hessian fly larvae with resistant wheat plants result in induction of plant defenses. One component of this defense response is the production of lectins that can function as feeding deterrents or antinutritional proteins when ingested by larvae. Wheat lectin genes that are responsive to avirulent Hessian fly larvae were cloned into expression vectors the proteins were harvested from E. coli. One of the lectins has been used in glycan binding arrays demonstrating its high affinity for high-mannose glycoproteins. This class of glycoproteins is common to larval midguts, suggesting that the lectin functions to disrupt the integrity of digestive membranes. Immunodetection indicated that the lectin increases in abundance once resistant plants are challenged with larvae and that larvae ingest the lectin. Messages encoding class III peroxidases also increased in abundance in resistant plants suggesting a role in resistance for genes involved in production of reactive oxygen species. 4. Hessian fly-resistance genes Previously published papers indicated that Hessian fly-resistance genes H26 and H32 reside in similar locations within the wheat genome. An integrated mapping approach demonstrated that H26 and H32 are either alternative alleles or tightly linked resistance genes that are effective against slightly different larval genotypes. Molecular markers were developed that will be useful in introgressing these genes into cultivars. +++++++++++++++++ Department of Entomology, Purdue University West Lafayette, Indiana 1. Progress toward understanding Hessian fly biotypes. It has long been hypothesized that single Avirulence (Avr) genes in the Hessian fly determine the virulence and avirulence of Hessian fly biotypes to specific Hessian fly resistance (R) genes in wheat. Taking a map-based approach to test this hypothesis, we have attempted to position the Avr mutations that condition virulence to R genes H6, H9, and H13 in wheat. Using backcross populations and recombinant inbred lines, we positioned Avr gene vH9, which corresponds to R gene H9, to a 120-kb segment of the genome near the telomere of the short arm of Hessian fly chromosome X1. Using the same approach, we positioned Avr gene vH13, which corresponds to R gene H13, to an 80-kb segment of the genome near the telomere of the short arm of Hessian fly chromosome X2. We then performed association mapping using Hessian fly populations collected in Georgia, Alabama, South Carolina, North Carolina, and Florida to determine if the positions of the genes could be further resolved. Results suggest that the mutations that caused virulence to both H9 and H13 can be easily observed on agarose gels and may serve as diagnostic markers for Hessian flies that are virulent to these genes. Results clearly indicate that Hessian fly virulence and avirulence to specific resistance genes in wheat results from mutations in single genes. Thus, the wheat-Hessian fly interaction clearly appears to have a gene-for-gene basis. The Hessian fly physical map is available as a Hessian fly Web FPC: http://genome.purdue.edu/WebAGCoL/Hfly/WebFPC/ +++++++++++++++++ Department of Entomology, Kansas State University Manhattan, Kansas 1. Feeding Behavior of Russian Wheat Aphid (Hemiptera: Aphididae) Biotype 2 in Response to Wheat Genotypes Exhibiting Antibiosis and Tolerance Resistance. Wheat genotypes containing the Dnx, Dn7, Dn6, and Dn4 genes for resistance to the Russian wheat aphid, Diuraphis noxia (Kurdjumov), along with Dn0, a susceptible control, were assessed to determine the categories of D. noxia biotype 2 (RWA2) resistance in each genotype and RWA2 feeding behaviors on Dnx and Dn0 plants by using the electronic penetration graph technique. At 14 d post-infestation, Dn0 plants exhibited intense chlorosis and leaf rolling, and all test genotypes expressed some degree of chlorosis and leaf rolling, except Dn7, which was not damaged. Both Dn7 and Dnx expressed antibiosis effects, significantly reducing the numbers of aphids on plants and the intrinsic rate of aphid increase. Dn6 plants appeared to contain tolerance, exhibiting tolerance index measurements for leaf and root dry weight and plant height that were significantly lower than those of the susceptible Dn0 plants. Principal component analyses indicated that antibiosis and leaf rolling data explained 80% of the variance among genotypes. Electronic penetration graph analysis demonstrated contrasting results between RWA1 and RWA2 phloem sieve element phase feeding events, but results indicated that Dnx resistance factors are present in the sieve element cells or phloem sap. Plants containing Dnx exhibit antibiosis resistance to D. noxia RWA2 similar to that in plants containing the rye-based Dn7 gene without the negative baking quality traits associated with Dn7. 2. Global Phylogenetics of an Invasive Aphid Species: Evidence for Multiple Invasions into North America. Critical to the study of an invasive species is understanding the number of invasions that have occurred, as well as the rate or potential of post-invasion adaptation and geographic range expansion. One virulent, invasive insect species that has caused much damage in the United States is the Russian wheat aphid, D. noxia. Past research on D. noxia has suggested that up to eight biotypes, defined based on their ability to damage different wheat and barley genotypes, have diverged and radiated across the western United States from a single, common ancestral invasion in 1986. The goal of our study was to address the basic question of are all biotypes of D. noxia the by-product of a single invasion or multiple invasions into North America?. We utilized the genome-wide technique of amplified fragment length polymorphisms, in combination with collections of D. noxia from around the World, to assess this question, as well as patterns of genetic divergence. We found that there were at least two invasions into North America, each resulting in subsequent post-invasion diversification that has since yielded multiple biotypes. 3. Categories of Resistance in Barley Against Russian Wheat Aphid, Diuraphis noxia Biotypes 1 and 2. The emergence of Russian wheat aphid, D. noxia, biotype 2 (RWA2) in Colorado has made all known Dn genes vulnerable except the Dn7 gene from rye, Secale cereale, and has warranted exploration for sources of resistance to RWA1 and RWA2. The mechanism of resistance with the resistant donor plants is considered important in terms of their influence to exert selection pressure over the aphid population for selection into new virulent population. We report tolerance and antibiosis categories of resistance to RWA1 and RWA2, in the barley cultivar Stoneham. The rate and degree of expression of resistance by Stoneham against RWA1 and RWA2 though not similar, is greater than Sidney, which showed partial resistance. Antixenosis was not apparent in either Sidney or Stoneham against either RWA1 or RWA2. Tolerance in Stoneham, expressed as reduced tissue dry weight loss and reduced tolerance index values, indicated that cultivation of Stoneham will delay the chances of RWA biotype selection. The reactions of Stoneham to RWA2 indicate that it is a good source of donor for future resistance breeding strategies against RWA. 4. Analysis of Transcripts and Proteins Expressed in the Salivary Glands of Hessian Fly Hessian fly (HF) (Mayetiola destructor) larvae are thought to manipulate host growth and metabolism through salivary secretions. However, the transcriptome and proteome of HF salivary glands have not been systematically analyzed. In this research, we analyzed Expressed-Sequence-Tags (EST) representing 6,106 cDNA clones randomly selected from four libraries made from dissected salivary glands. We also analyzed the protein composition of dissected salivary glands using one- and two-dimensional gel electrophoresis as well as LC-MS/MS analysis. Transcriptomic analysis revealed that approximately 60% of the total cDNA clones and 40% of assembled clusters encoded secretory proteins (SP). The SP-encoding cDNAs were grouped into superfamilies and families according to sequence similarities. In addition to the high percentage of SP-encoding transcripts, there was also a high percentage of transcripts encoding proteins that were either involved directly in protein synthesis or in house-keeping functions that provide conditions necessary for protein synthesis. Proteomic analysis also revealed a high percentage of proteins involved in protein synthesis either directly or indirectly. The high percentage of SP-encoding transcripts and high percentage of proteins related to protein synthesis suggested that the salivary glands of HF larvae are indeed specialized tissues for synthesis of proteins for host injection. However, LC-MS/MS analysis of 64 proteins did not identify any SPs corresponding to the cDNA sequences. The lack of accumulation of SPs in the salivary glands indicated the SPs were likely secreted as soon as they were synthesized. 5. Differential Responses of Wheat Inhibitor-Like Genes to Hessian Fly Attacks during Compatible and Incompatible Interactions. Four groups of inhibitor-like genes encoding proteins with diverse structures were identified from wheat. The majority of these genes were upregulated by avirulent Hessian fly, Mayetiola destructor (Diptera: Cecidomyiidae), larvae during incompatible interactions, and were downregulated by virulent larvae during compatible interactions. The upregulation during incompatible interactions and downregulation during compatible interactions resulted in 4- to 30-fold differences between the expression levels in resistant plants and those in susceptible plants. The increased expression of inhibitor-like genes during incompatible interactions suggested that these genes are part of defense mechanisms in wheat against Hessian fly attacks, whereas the downregulation of these genes during compatible interactions suggested that virulent larvae can suppress plant defenses. Both the upregulation of the inhibitor-like genes during incompatible interactions by avirulent larvae and the downregulation during compatible interactions by virulent larvae were through mechanisms that were independent of the wound response pathway. 6. Testing Hessian Fly Populations for Virulence to Known Resistance Genes. In recent years, the number of wheat fields heavily infested by Hessian fly has increased in the Great Plains of the U.S. Historically, resistance genes in wheat have been the most efficient means of controlling this insect pest. To determine which resistance genes are still effective in this area, virulence of six Hessian fly populations from Texas, Oklahoma, and Kansas was determined, using the resistance genes H3, H4, H5, H6, H7H8, H9, H10, H11, H12, H13, H16, H17, H18, H21, H22, H23, H24, H25, H26, H31, and Hdic. Five of the tested genes, H13, H21, H25, H26, and Hdic, conferred high levels of resistance (>80% of plants scored resistant) to all tested populations. Resistance levels for other genes varied depending on which Hessian fly population they were tested against. Biotype composition analysis of insects collected directly from wheat fields in Grayson county, Texas, revealed that the proportion of individuals within this population virulent to the major resistance genes was highly variable (89% for H6, 58% for H9, 28% for H5, 22% for H26, 15% for H3, 9% for H18, 4% for H21, and 0% for H13). Results also revealed that the percentages of biotypes virulent to specific resistance genes in a given population are highly correlated (r2 = 0.97) with the percentages of susceptible plants in a virulence test. This suggests that virulence assays, which require less time and effort, can be used to approximate biotype composition. We are currently looking to survey several locations in Kansas and have recently obtained a sample from Eastern Colorado. 7. K-State Wheat Insect Extension Activities We continue to add to revise our websites: (http://www.entomology.ksu.edu/DesktopDefault.aspx?tabindex=195&tabid=405) (http://www.oznet.ksu.edu/library/ENTML2/MF745.PDF). (http://www.oznet.ksu.edu/library/plant2/mf991.pdf). (http://www.oznet.ksu.edu/library/entml2/MF2866.pdf) (http://www.oznet.ksu.edu/library/entml2/MF2823.pdf ) (http://www.oznet.ksu.edu/library/entml2/MF2832.pdf). +++++++++++++++++ Department of Entomology, North Dakota State University Fargo, North Dakota 1. 2008 Hessian fly survey Objectives for 2008 were to determine if the sex-pheromone blend would be useful for monitoring Hessian fly in a field setting, and to establish the geographic distribution, seasonal abundance and number of generation per year of the Hessian fly in North Dakota. Six locations that represent the various climatic and cropping regions of the state were selected for the project. Three traps containing the sex-pheromone lure were deployed at each location. The traps were located in or near wheat plots with each trap positioned 30-60 cm above the ground. The sticky cards on the floor of each trap were replaced each week and the pheromone lure was replaced every 2-4 weeks. Ideally the traps were deployed immediately after the spring thaw and maintained in the field until fall freeze-up. From the 2008 trap collections it was determined that: a. North Dakota Hessian fly responded to the 5-component pheromone lure. b. Male flies were recovered from all six locations, which suggests that Hessian fly are distributed state-wide. c. Seasonal abundance of Hessian fly in 2008 was generally characterized by emergence taking place from early May into October, with 1 or 2 peaks in emergence occurring midsummer and a smaller peak in late September. d. Peak fly emergence generally occurred in late July to early August, this indicates that North Dakota Hessian fly did not go into aestivation during the warmest part of the growing season. e. In 2008, the fall emergence of Hessian fly coincided with or was slightly after the suggested planting period for winter wheat in North Dakota, this seems to imply that a fly-free date may not have worked. 2. Wheat stem sawfly in 2008 Wheat stem sawfly continues to be a concern for farmers in the southwestern and south-central parts of the state. Sweep-net samples from some locations yielded more than 150 sawfly per 100 sweeps. Although sawfly are usually considered a problem isolated to the western part of the state, reports from numerous growers indicate that it is moving eastward across the state. The most common method for controlling sawfly is with solid stemmed varieties. Farmers generally do not like using the solid stem varieties because of yield drag associated with the solid stem trait. NDSW0449, a new hard red spring wheat variety which has a semi-solid stem is in the process of being released. This variety has sawfly resistance and appears to yield better than most of the current sawfly-resistant varieties including Ernest which is the last NDSU variety released with sawfly resistance. The use of insecticides to control sawfly is also being considered. Dr. Janet Knodel is studying the use of insecticidal seed treatments such as Cruiser as a planting time management option. In addition to seed treatments, Dr. Knodel is also evaluating the application of insecticides at the 4-6 leaf and flag leaf stage to control adult sawfly as they emerge. Other strategies to control adult sawfly are underway in the neighboring state of Montana. Currently they are studying Braconid wasps as potential Biological control agents. If the researchers in Montana are successful, the use of parasitic wasps might also improve the sawfly situation in North Dakota. +++++++++++++++++ USDA, ARS, SPA Wheat, Peanut and Other Field Crops Research Unit Stillwater, Oklahoma 1. Barley Breeding Program A total of 50 RWA-resistant barley germplasm lines have been released to date. STARS 0501B STARS 0507B are 6-rowed winter germplasm lines in a feed barley background, STARS 0601B - STARS 0619B are 6-rowed, spring germplasm lines in 4 malting barley backgrounds, STARS 0620B - STARS 0636B are 2-rowed spring barley germplasm lines in 4 malting barley backgrounds, and STARS 0637B- STARS 0643B are 2-rowed spring barley germplasm lines in 3 feed barley backgrounds. These germplasm lines encompass 36 different sources of resistance. These lines were developed by USDA-ARS in Stillwater, and evaluated and selected in Idaho, Colorado and/or Nebraska with assistance of. Phil Bregitzer and Don Obert, USDA-ARS, Aberdeen, ID, Frank Peairs, Colorado State University, and Gary Hein, University of Nebraska. Increases have been made prior to release of 10, RWA-resistant, 6-rowed, winter, feed barley germplasm lines resistant to both Greenbug and RWA. Four RWA-resistant barley cultivars are now available. Sidney and Stoneham are 2-rowed feed barleys bred for the high and dry plains of eastern CO and western NE. Burton and RWA1758 are 2-rowed spring feed barleys developed for dryland or irrigated production from ID to CO. Sidney and Burton have resistance from STARS 9301B and Stoneham and RWA1758 have resistance from STARS 9577B. QTL analysis done in cooperation with Shipra Mittal and Lynn Dahleen, USDA-ARS, Fargo, identified 3 QTLs associated with RWA resistance in STARS 9301B. Only 2 of these three were associated with resistance in STARS 9577B one of which showed a different gene action than in STARS 9301B. A cooperative project with Texas AgriLife is ongoing to map RWA resistance genes in 3 winter barley germplasm lines and Rsg1 and Rsg2 greenbug resistance genes. A breeding program has been initiated to develop winter, hulless, feed barleys resistant to both RWA and Greenbug, adapted to Oklahoma, and suitable for ethanol production. Hulless winter barleys, selected for adaptation to OK as well as percent starch of grain, were crossed as males to RWA and greenbug resistant lines developed by USDA-ARS in Stillwater. Crossing and backcrossing of hulless lines to selected females is ongoing. 4,000 F4 RWA/GB resistant hulless head rows are in the field this year for evaluation. 4,000 RWA/GB resistant F3 are being increased to F4 in the greenhouse and 104 hulless F2 bulks were planted in Woodward in the fall of 2008 for head selection. A seedling screening test for BCOA resistance has been developed and tested for repeatability. Two replications of the Barley Core Collection (960 accessions) were screened with this new technique in the summer of 2006. Survivors were grown in pots in the greenhouse and data collected for plant height, grain yield, and yield components. Five seed each of 364 survivors were screened with BCOA in the summer of 2007. An aphid free set of identical flats was also grown. Selected survivors from the screening were rescued and, along with their matching non-infested checks, transplanted into pots in the greenhouse. Infested and non-infested pots for each line were placed side by side on greenhouse benches for increase. Yield and yield components were measured in the spring of 2008. Results indicated that the proposed 1-7 rating scale should be downsized to 1-4. Further confirmation of the rating scale is planned for the summer of 2009. 2. Wheat Breeding Program We have continued to work on the purification of wheat differentials for use in Russian wheat aphid biotype screening trials. This material is available to other locations for use in screening tests. Usually the original resistance source for these differentials is a Plant Introduction received from the Germplasm Resources Information Network (GRIN); this USDA facility stores, maintains, and propagates material in a manner that retains as much of its original diversity as possible. Because most of the RWA resistant Plant Introductions are landraces that are highly heterogeneous, researchers cannot simply go back to GRIN to request another sample of a Plant Introduction and expect that sample to be the same as a previous sample. Inherent differences from location to location, and even within a single location, make the use of standardized differentials imperative. We have continued in the quest to find additional sources of RWA resistance that are resistant to RWA1 and RWA2. In our tests, germplasm release STARS-0601 has continued to have the strongest resistance available to all RWA biotypes against which it has been tested. 3. RWA Biotype Diversity and Ecology Studies have been ongoing since 2006 on the ecology of overwintering RWA in diverse environments to determine if and how sexual reproduction (holocycle) occurs and its role in biotype development. Only a few populations collected from the wheat belt east of the Rocky Mountains produced only oviparae, thus were not holocyclic. In 2006, this research was further expanded to include the Colorado Plateau where three other Diuraphis spp. endemic to the U.S.A., D. tritici, D. nodulus, and D. frequens, were known to produce overwintering eggs. In the spring of 2007, a small holocyclic population of RWA was located in Dolores County, Colorado. Ninty-three fundatricies were collected from grasses and wheat and identified by morphological traits at this site and evaluated on 16 plant entries that included Dn1-Dn9, CI 2401, and 2414-11 RWA resistance sources, two susceptible wheat entries, and the resistant barely sources Stars 9577B, STARS 9301, and susceptible Schyler. These evaluations determined that the population was comprised of 47 phenotypes which included biotypes RWA1, 2, 6, 7, and 8. Terry Randolf and Frank Peairs (CSU), independently evaluated 9 fundatricies from this site and identified 5 unique phenotypes. Although we were not able to locate this site in time to verify the presence of RWA males, dead oviparae were found in wheat collected from this site. We concluded that RWA can go holocyclic and lay overwintering eggs that hatch in late March. The genetic recombination that resulted from sexual reproduction is responsible for the high degree of variation in the population we sampled. Studies are ongoing to further characterize the phenotypic and genetic diversity of the RWA populations from the Colorado Plateau region. Future efforts will include monitoring locations throughout the USA to characterize RWA biotypic diversity and identify other ecological zones where RWA may go holocyclic and generate the biotypic diversity that is currently being found in the field. 4. Molecular Ecology of Cereal Aphids and their Natural Enemies The cytochrome oxidase subunit I (COXI) mtDNA gene was sequenced the from following species which are all autoecious holocyclic on grasses; D. noxia, D. tritici, D. frequens, D. mexicana, Schizaphis graminum, Sipha flava, S. elegans, and Sitobion avenae. Based on the COXI, DNA barcoding successfully identified and separated the 4 Diuraphis aphids at any life stage, including eggs. This assay can be used in field surveys to accurately determine eggs, nymphs, adults, and sexuales. In research with Dr. Jack Dillwith (Oklahoma State University), it was determined that although individual clones of Diuraphis noxia could be distinguished by cuticular hydrocarbon (CHC) profiles, biotypes 1 and 2 could not. There was continuous overlap in CHC profiles between the two biotypes. CHCs are another character in which D. noxia shows phenotypic plasticity, even within biotypes. 5. Greenbug Ecology and Biotypic Diversity A regional survey of Hymenopterous parasitoids reared from mummified cereal aphids has been completed. Parasitoids were collected from the western slope of the Rocky Mountains in New Mexico, Colorado, and Wyoming. Parasitoids recovered included, Aphilinus albipodus , 2 unknown A. spp., Diaeretiella rapae, Lysiphlebus testaceipes, Aphidius colemani, and Ephedrus plagiator. Parasitoids attacked aphids on a variety of host plants, including wheat, barley, mountain brome, lovegrass, and crested wheatgrass. Collaborative work with Texas AgriLife Research, Amarillo, (Y. Weng, H. Lu, and J. Rudd) focused on mapping greenbug resistance genes Gb2 and Gb6 continues, and thus far, eight markers linked with Gb2 and Gb6 have been identified. In 2008, Collaborative research with the Energy Biosciences Institute, University of Illinois (J. Prasifka and J. Bradshaw) was initiated to assess the role of potential biofuel crops as hosts/reservoirs for agricultural pests (primarily aphids). 6. Remote sensing of cereal aphids In conjunction with collaborator Georges Backoulou from Oklahoma State University we are reporting on progress in remote sensing for monitoring Russian wheat aphids and greenbugs in wheat. The objectives were to assess whether variation in light reflectance form plants infested with varying densities of greenbugs could be detected using airborne imaging obtained with a multi-spectral digital camera mounted in a fixed wing aircraft. In a replicated experiment where greenbug density was manipulated in 1-m2 plots of two winter wheat varieties (Jagger and OK 101) planted in a field, we found that wheat infested with greenbugs exhibited different reflectance responses for the two varieties. Both varieties showed a reduction in the normalized differenced vegetation index (NDVI) as greenbug density increased as indicated by a negative slope for the regression of NDVI on greenbug density. The slope for Jagger was greater in magnitude (-0.0031) than the slope for OK 101 (-0.0011). The regressions indicated that NDVI decreased more rapidly as greenbug density increased for Jagger than for OK 101. A second vegetation index, Green NDVI, responded similarly to NDVI with increasing greenbug density. In large plots in four production winter wheat fields we found significant negative correlations between greenbug density and the above mentioned vegetation indices for three of the four fields. For the Russian wheat aphid we assessed the potential of using multispectral imagery and a spatial pattern recognition approach to identify and spatially quantify D. noxia infestations within wheat fields. Data used included multispectral imagery acquired from April - May 2005, and 2007, in the vicinity of Boise City, OK. Stress to wheat in fields was grouped into categories: D. noxia, drought and cultural issues. ERDAS Imagine software was used to process and analyze images. FRAGSTATS was used to quantify spatial pattern. Ten landscape metrics were computed at the class level for each stress factor. The analysis of variance of each landscape metric revealed that the shape of each kind of stress was different. The combination of multispectral data and landscape metrics made it possible to distinguish areas in fields infested by D. noxia from areas affected by drought or cultural issues. +++++++++++++++++ Department of Entomology and Plant Pathology Oklahoma State University, Stillwater, Oklahoma 1. Projects in 2008 a. Intraguild Interactions among Schizaphis graminum, Lysiphlebus testaceipes, and Coccinellidae in Winter Wheat. b. Predator Movement in Wheat Cropping Systems. Studies have been initiated to examine the colonizing ability of Carabidae. Trapping and molecular techniques will be used to describe movement. c. Evaluations of Variety and Insecticidal Seed Treatments for Hessian Fly Management. Field evaluations of elite lines of wheat for control of Hessian fly. In addition, a survey of wheat fields was conducted through the Cooperative Agricultural Pest Survey (CAPS). Hessian fly was becoming more widely distributed, but Russian wheat aphid was not present in any of the fields checked. Barley Yellow Dwarf virus and Wheat Streak Mosaic virus were also detected. d. Synopsis of Arthropod Pest Activity in Wheat, 2007-2008 Overall, pest pressure in 2007-08 was mild. An outbreak of armyworms occurred in spring of 2007 and an outbreak of fall armyworms occurred in fall 2008. Greenbug pressure is building as of now. Hessian fly is increasing in Oklahoma. Some fields were severely infested. Problem is growing. +++++++++++++++++ USDA-ARS North Central Agricultural Research Laboratory Brookings, South Dakota 1 Overview of Cereal-Aphid Research Activities and Accomplishments The rice root aphid, Rhopalosiphum rufiabdominalis (Sasaki), is distributed worldwide and colonizes a wide range of plants. However, relatively little is known about the suitability of different host plants, optimal rearing techniques, and the aphids impact on plant fitness. To improve understanding of these factors, laboratory experiments were conducted to compare the abundance of rice root aphid on plants grown using three different soil-surface media and among selected monocotyledonous and dicotyledonous plants. Rice root aphid was more abundant on plants grown with a sandy soil surface than a surface with fine wood chips or only bare non-sandy soil. Rice root aphid was more abundant on Elbon rye than on Bart 38, Dart, Fletcher and Ramona 50 wheat. More winged rice root aphids were produced on Elbon rye than on Dart wheat, but the number of winged aphids on Elbon rye did not differ from that on other wheat lines. Rice root aphid was more abundant on Elbon rye and TAM 110 wheat than on Marmin, Marshall and Sharp wheat. Additional observations with monocotyledonous plants showed that abundance of rice root aphid on Kivu 85 triticale was comparable to that on Elbon rye. Rice root aphid did not reproduce on potato or soybean, although winged adults persisted up to 24 days on caged potato plants. The differential abundance of rice root aphid on plants has implications with regard to colony rearing, future experiments and pest management.

Publications

Andersson, MN, J Haftmann, JJ Stuart, S Cambron, MO Harris, SP Foster, S Franke, W Francke, Y Hilbur. 2008. Identification of sex pheromone components of the Hessian fly, Mayetiola destructor. J Chem. Ecol. DOI 10.1007/s10886-008-9569-1. Aubrey A. Weiland, Frank B. Peairs, Terri L. Randolph, Jeffrey B. Rudolph, Scott D. Haley, and Gary J. Puterka. 2008. Biotypic Diversity in Colorado Russian Wheat Aphid (Hemiptera: Aphididae) Populations. J. Econ. Entomol. 101(2): 569-574. Brewer, M. J., T. Noma, and N. C. Elliott. A landscape perspective in managing vegetation for beneficial plant-pest-natural enemy interactions: a foundation for areawide pest management. In O. Koul, G. W. Cuperus, and N. C. Elliott (eds.) Areawide Pest Management: Theory and Implementation. CAB International, Wallingford Oxfordshire, UK. 2008. Brewer, M. J., T. Noma, N. C. Elliott, A. N. Kravchenko, and A. L. Hild. A landscape view of cereal aphid parasitoid dynamics reveals sensitivity to farm- and region-scale vegetation structure. European Journal of Entomology 105: 503-511. 2008. Catana, V., N. Elliott, K. Giles, M. Mirik, D. Porter, G. Hein, F. B. Peairs, and J. Michels. 2008. The role of databases in areawide pest management. Pages 142-158 in O. Koul, G. W. Cuperus, and N. C. Elliott, eds., Areawide Pest Management: Theory and Implementation. CAB International. Cambridge, MA. Catana, V., N. Elliott, K. Giles, M. Mirik, D. Porter, G. Hein, F. Peairs, and J. Michels. The role of databases in areawide pest management. In O. Koul, G. W. Cuperus, and N. C. Elliott (eds.) Areawide Pest Management: Theory and Implementation. CAB International, Wallingford Oxfordshire, UK. 2008. Chen M.S., Echegaray E., Whitworth, R.J., Wang H., Sloderbeck, P.E., Knutson, A., and Giles K.L. (2009) Virulence analysis of Hessian fly (Mayetiola destructor) populations from Texas, Oklahoma, and Kansas. Journal of Economic Entomology. In press. Chen, M.S., Zhao, H.X., Zhu, Y.C., Scheffler, B., Liu, X.M., Liu, X., Hulbert, S., and Stuart, J.J. (2008) Analysis of Transcripts and Proteins Expressed in the Salivary Glands of Hessian Fly (Mayetiola destructor) Larvae. Journal of Insect Physiology. 54:1-16. Chen, M-S, H-X Zhao, YC Zhu, B Scheffler, X Liu, X Liu, S Hulbert, and JJ Stuart. 2008. Analysis of transcripts and proteins expressed in the salivary glands of Hessian fly (Mayetiola destructor) larvae. J Insect Phys. 54:1-16. DeWolf, Erick and Phillip E. Sloderbeck, 2008. Wheat Variety Disease and Insect Ratings 2008. Kansas State University Agricultural Experiment Station and Cooperative Extension Service. MF991. Elliott, N. C., D. W. Onstad, and M. J. Brewer. History and ecological basis for Areawide pest management. In O. Koul, G. W. Cuperus, and N. C. Elliott (eds.) Areawide Pest Management: Theory and Implementation. CAB International, Wallingford Oxfordshire, UK. 2008. Enali, S., R. Anathakrishnan, T. Niide, L. Starkus, S. Starkey, and C. M. Smith. 2009. Comparisons of wheat and barley resistance to Russian wheat aphid biotype 2. Arthropod- Plant. Interact. 5: (In Press). Giles, K., G. L. Hein, and F. B. Peairs. 2008. Areawide pest management of cereal aphids in dryland wheat systems of the Great Plains, USA. Pp. 441 - 466 in: Koul, O., G. Cuperus, and N. Elliott, eds., Areawide Pest Management: Theory and Implementation. CAB International. Cambridge, MA. Giovanini MP, Saltzmann KD, Puthoff DP, Gonzalo M, Ohm HW Williams CE. 2007. A novel wheat gene encoding a putative chitin-binding lectin is associated with resistance against Hessian fly. Mol. Plant Path. 8:69-82. 2007. Gutsche, A., T. Heng-Moss, G. Sarath, P. Twigg, Y. Xia, G. Lu, and D.W. Mornhinweg. 2008. Gene expression profiling of tolerant barley in response to Diuraphis noxia (Hemiptera: Aphididae) feeding. Bull. Entomol. Res. Bulletin of Entomological Research, Page 1-11. Haley, S.D., J.J. Johnson, F.B. Peairs, J.S. Quick, J.A. Stromberger, J.D. Butler, H.R. Miller, E.E. Heaton, J.B. Rudolph, B.W. Seabourn, G. Bai, Y. Jin, J.A. Kolmer and X. Chen. 2008. Registration of Bill Brown Wheat. J. Plant Registrations 2: 218-223. Hesler, L.S. & S.D. Kindler. 2007. Abundance of rice root aphid among selected plant species and on plants grown with different soil-surface media. Great Lakes Entomol. 40:83-90. Hodek, I. and J.P. Michaud. 2008. Why is Coccinella septempunctata so successful? Eur. J. Entomol. 105: 1-12. Holly Davis, Ming-Shun Chen, Jeff Whitworth, Gary Cramer, Brian McCornack, Phil Sloderbeck, Aqeel Ahmad and Mary Knapp. 2009. Hessian fly-free date in Kansas: Is it still valid after 70+ years?. Joint Meeting of the Southwestern Branch of the Entomological Society of America and WERA066 (Western Extension/Education Research Activity), February 2009, Stillwater, Oklahoma. Koul, O, G. W. Cuperus, and N. C. Elliott (eds.) Areawide Pest Management: Theory and Implementation. CAB International, Wallingford Oxfordshire, UK. 2008. Lazzari, S., S. Starkey, J. Reese, A. Ray-Chandler, and C. M. Smith. 2009. Feeding behavior of Russian wheat aphid (Hemiptera: Aphididae) biotype 2 in response to wheat genotypes exhibiting antibiosis and tolerance. J. Econ. Entomol. 102: (Accepted). Liu, X., J. L. Marshall, P. Stary, O. Edwards, G. Puterka, L. Dolatti, M. E. Bouhssini, J. Malinga, and C. M. Smith. 200#. Global phylogenetics of an invasive aphid species: Evidence for multiple invasions into North America. J. Heredity. (submitted). Merrill, S. C., F. B. Peairs, H. R. Miller, T. L. Randolph, J. B. Rudolph, and E. E. Talmich. 2008. Reproduction and development of Russian wheat aphid Biotype 2 on crested wheatgrass, intermediate wheatgrass, and susceptible and resistant wheat. J. Econ. Entomol. 101: 541-545. Merrill, S., T. Randolph, C. B. Walker, and F. B. Peairs. 2008. 2007 Russian wheat aphid biotype survey results for Colorado. Pp. 43 - 44 in Johnson, J. J., ed. 2008. Making better decisions: 2007 Colorado wheat variety performance trials. Colorado State Univ. Agric. Exp. Sta. Tech. Rep. TR08-08, 47 pp. Michaud, J.P. and J.L. Jyoti. 2008. Dietary complementation across life stages in the polyphagous lady beetle Coleomegilla maculata. Entomologia Experimentalis et Applicata 126: 40-45 Michaud, J.P. and J.L. Jyoti. 2007. Dietary complementation across life stages in a polyphagous lady beetle, Coleomegilla maculata. Entomol. Exp. Appl. 126: 40-45. Mike Smith, Xuming Liu, Xiang Liu, Sharon Starkey, JianFa Bai, L. J. Wang and Ming-Shun Chen. 2009. Wheat Plant Gene Expression in Response to Russian Wheat Aphid Feeding. Joint Meeting of the Southwestern Branch of the Entomological Society of America and WERA066 (Western Extension/Education Research Activity), February 2009, Stillwater, Oklahoma. Miller, H. R. and F. B. Peairs. 2008. Ground beetles (Coleoptera: Carabidae) in Colorado dryland cropping systems. Southwestern Entomologist 33: 31 - 42. Mittal, S., L.S. Dahleen, and D.W. Mornhinweg. 2008. Locations of quantitative trait loci (QTL) conferring Russian wheat aphid resistance in barley germplasm STARS-9301B. Crop Sci. 48(4):1452-1458. Mittapalli, O. and Shukle, R. H. 2008. Molecular characterization and responsive expression of a defender against apoptotoic cell death homologue from Hessian fly, Mayetiola destructor. Comparative Biochemistry and Physiology Part B, 149; 517-523. Mittapalli, O., Neal, J. J., and Shukle, R. H. 2007. Antioxidant defense response in a galling insect. Proceedings of the National Academy of Sciences (USA); 104(6); 1889-1894. Mittapalli, O., Neal, J. J., and Shukle, R. H. 2007. Tissue and life stage specificity of glutathione S-transferase expression in the Hessian fly, Mayetiola destructor: Implications for resistance to host allelochemicals. Journal of Insect Science, 7; article 20. Mittapalli, O., Sardesai, N., and Shukle, R. H. 2007. cDNA cloning and transcriptional expression of a peritorphin-like gene in the Hessian fly, Mayetiola destructor (Say). Archives of Insect Biochemistry and Physiology, 64; 19-29. Mornhinweg, D.W., P. Bregitzer, and D.R. Porter. 2007. Registration of nineteen spring six-rowed barley germplasm lines resistant to Russian wheat aphid. Journal of Plant Registrations 1: Journal of Plant Registrations 1: 137-138. Mornhinweg, D.W., P. Bregitzer, and D.R. Porter. 2007. Registration of seventeen spring two-rowed barley germplasm lines resistant to Russian wheat aphid. Journal of Plant Registrations 1: 1 (2): 135-136. Mornhinweg, D.W., P.P. Bregitzer, and D.R. Porter. 2008. Registration of seven spring two-rowed barley germplasm lines resistant to Russian wheat aphid. J. Plant Registrations 2(3):1-5. Peairs, F. B., J. B. Rudolph, T. L. Randolph, and S. Merrill. 2008. 2007 Colorado field crop insect management research and demonstration trials. Colorado State Univ. Agric. Exp. Sta. Tech. Rep. TR08-06, 34 pp. Randolph, T. L., S. C. Merrill, and F. B. Peairs. 2008. Reproductive rates of Russian wheat aphid (Hemiptera: Aphididae) Biotypes 1 and 2 on a susceptible and a resistant wheat at three temperature regimes. J. Econ. Entomol. 101: 955 - 958. Saltzmann KD, Giovanini MP, Zheng, C, Williams CE. 2008. Viruent Hessian fly larvae manipulate the free amino acid content of host wheat plants. J. Chem. Ecol. 34:1401-1410. Seifers, D.L., T.J. Martin, T.L. Harvey, J.P. Fellers, & J.P. Michaud. 2009. Identification of the wheat curl mite as the vector of Triticum mosaic virus. Plant Disease 93: 25-29 Shufran, K.A., D.W. Mornhinweg, C.A. Baker, and D.R. Porter. 2007. Variation to cause host injury between Russian wheat aphid (Homoptera: Aphididae) clones virulent to Dn4 wheat. J. Econ. Entomol. 100(5):1685-1691. Shukle, R. H., Mittapalli, O., Morton, P. K., Chen, M. S. 2009. Characterization and expression analysis of a gene encoding a secreted lipase-like protein expressed in the salivary glands of the larval Hessia fly, Mayetiola destructor (Say). Journal of Insect Physiology, 55; 104-111. Shukle, R. H., Yoshiyama, M., Morton, P.K., Johnson, A. J., and Schemerhorn, B.J. 2008. Tissue and developmental expression of a gene from Hessian fly encoding an ABC-active-transporter protein: Implications for Malpighian tubule function during interactions with wheat. Journal of Insect Physiology, 54(1); 146-154. Sloderbeck, Phillip E., J.P. Michaud and R. Jeff Whitworth. Wheat Insect Management 2008. Kansas State University Agricultural Experiment Station and Cooperative Extension Service. MF745. Smith, C. M. 2009. Advances in Breeding for Host Plant Resistance. pp. 235-246, In: Integrated Pest Management, eds. E. B. Radcliffe, W. D. Hutchison and R. F. Cancelado. Cambridge University Press. Sotelo, P., S. Starkey, P. Voothuluru, G. Wilde, and C. M. Smith. 2009. Resistance to Russian Wheat Aphid Biotype 2 in CIMMYT Synthetic Hexaploid Wheat Lines. J. Econ. Entomol. 102: (In Press). Subramanyam S, Smith DF, Clemens JC, Webb MA, Sardesai N, Williams CE. 2008. Functional characterization of HFR-1, a high-mannose N-glycan-specific wheat lectin induced by Hessian fly larvae. Plant Physiology 147:1412-1426. Tarver, M. R., Shade, R. E., Shukle, R. H., Moar, Muir, W. M., Murdock, L. M., and Pittendrigh, B. P. 2007. Pyramiding of insecticidal compounds for control of the cowpea bruchid (Callosobruchus Maculatus F.). Pest Management Science, 63(5); 440-446. Weiland, A. A., F. B. Peairs, T. L. Randolph, J. B. Rudolph, S. D. Haley, and G. J. Puterka. 2008. Biotypic diversity in Colorado Russian wheat aphid (Hemiptera: Aphididae) populations. J. Econ. Entomol. 101: 569-574. Whitworth, R. Jeff and Aqeel Ahmad, 2008. Bird Cherry-oat Aphid. Kansas State University Agricultural Experiment Station and Cooperative Extension Service. MF-2823 Whitworth, R. Jeff and Aqeel Ahmad, 2008. Flea Beetle. Kansas State University Agricultural Experiment Station and Cooperative Extension Service. MF-2832 Whitworth, R. Jeff, Phil Sloderbeck, Holly Davis and Gary Cramer, 2009. Hessian Fly, Kansas State University Agricultural Experiment Station and Cooperative Extension Service. MF-2866. Wu J.-X., Liu X.-M., Zhang S.-Z., Y.-C. Zhu, Whitworth R.J., Chen M.-S. (2008) Differential responses of wheat inhibitor-like genes to Hessian fly, Mayetiola destructor, attacks during compatible and incompatible interactions. Journal of Chemical Ecology. 34:1005-1012. Wu, Y. and Huang, Y. 2008. Molecular mapping of QTLs for resistance to the greenbug Schizaphis graminum (Rondani) in Sorghum bicolor (Moench). Theor Appl Genet. 117:117-124. Xiang Liu, Jeremy Marshall, Sharon Starkey, Petr Starry, John Burd, Gary Puterka, L. Dolatti, Owain Edwards, Mustapha El Bouhssini, Joyce Malinga, Jacob Lage, and Mike Smith. 2009, Global Phylogenetics of an Invasive Aphid Species: Evidence for Multiple Invasions into North America. Joint Meeting of the Southwestern Branch of the Entomological Society of America and WERA066 (Western Extension/Education Research Activity), February 2009, Stillwater, Oklahoma. Zhu, L, X Liu, X Liu, R Jeannotte, JC Reese, M Harris, JJ Stuart, and M-S Chen. 2008. Hessian fly (Mayetiola destructor) attack causes a dramatic shift in carbon and nitrogen metabolism in wheat. Mol. Plant-Microbe Interactions 21:7078 Zhu, L., Liu, X.M., Liu, X., Jeannotte, R., Reese, J.C., Harris, M., Stuart, J.J., and Chen, M.S. (2008) Hessian Fly (Mayetiola Destructor) Attack Causes Dramatic Shift in Carbon and Nitrogen Metabolism in Wheat. Molecular Plant-Microbe Interactions. 21:70-78.

Impact Statements

Improve knowledge of cereal arthropods among scientists, producers and other interested clientele.
Develop new or improved management practices for cereal arthropods.
Monitor for newly introduced pests or the development and spread of new, more damaging, biotypes.

Date of Annual Report: 12/10/2010

Report Information

Annual Meeting Dates: 09/21/2010 - 09/22/2010
Period the Report Covers: 10/01/2009 - 09/01/2010

Participants

C. Michael Smith, Kansas State University;
Christie Williams, USDA-ARS, West Lafayette, IN;
David Weaver, Montana State University;
Ed Bynum, Texas Agrilife Extension;
Frank Peairs, Colorado State University;
Gary Puterka, USDA-ARS, Stillwater;
Marion Harris, North Dakota State University;
Scott Haley, Colorado State University;
Pat Byrne, Colorado State University;
Scott Nicholson, USDA - ARS, Stillwater, OK;
Terri Randolph, Colorado State University;

Brief Summary of Minutes

Summary of Decisions Made for WERA-066, September 21, 2010.

1) Decision was made to renew WERA-066 and focus on maintaining high quality, attractive programming.
2) Self-imposed deadline for the 1st draft of the new WERA-066 proposal is January 2011.
3) Site for next meeting is Minneapolis, MN in March 2012 and is to be a joint meeting with the International Plant Resistance to Insects meeting.
4) Program Chair will be Gary Puterka, and secretary elect is Mike Smith for the 2012 Meeting.

Minutes of Meeting September 21, 2010

8:30 am -- Called Meeting to Order Followed by Invited Speaker Presentations
Chair Christie Williams called the meeting to order and began with a round of introductions by those in attendance. Gary Puterka then read the minutes of the 2009 meeting that was held in Stillwater, OK. Christi Williams moved that the minutes be approved and Scott Nicholson seconded the motion, which then carried.

8:45 am -- Presentation by David Weaver - Wheat Stem Sawfly Research in Montana. The wheat stem sawfly is a significant pest of wheat causing 100-700 million in losses/year in the US. Role of wheat volatiles in WSS preference is being investigated. Use of selected cultivars preferred by WSS as a trap crop showed success in managing WSS. Orange wheat Blossom Midge continues to be present in high numbers in the Flathead Valley with low parasitism evident. Other affected areas in the main wheat belt of Montana are using pheromone traps to monitor OWBM activity with none presently being detected.

9:45 am -- Presentation by Gary Puterka - Russian Wheat Aphid Biotype Problem and Role of Sexual Reproduction in Biotypic Diversity. There is currently eight biotypes. Site found in western Colorado in 2007 that overwintered as eggs and produced about 50% biotypic variation at one site and over 40 new biotypes. Stressed the need to monitor biotypic diversity.

10:45 am -- Presentation by Frank Peairs - Russian wheat aphid and wheat research in Colorado. Russian wheat aphid is currently at low levels. Research was presented on biocontrol factors affecting RWA. Hessian fly is becoming a big concern for Colorado wheat. Populations are primarily in the south-eastern part of the state and are presently being monitored. Russian wheat aphid eggs were located during a study on grasses hosts of RWA. There is strong evidence that mountain wind currents disperse aphids to the lower elevations where wheat is produced.

11:30 am -- Presentation by Mike Smith - Molecular Investigation of RWA Populations in the World and Paths of Invasion, Host plant mechanisms Studies on RWA resistant Wheat. Molecular evidence indicates that the US has had several RWA introductions. Microarray studies on plant response indicated Jasmonic and salicylic pathways are up regulated during RWA feeding. Early defense pathway expression is the area of focus. In aphid-plant studies, antibiosis in some wheat varieties appears to be the operating mechanism for RWA resistance in wheat.

2:00 pm -- Presentation by Pat Byrne - CAP Grant Process and How Successful Grants are Organized. Successful grant funding is favored by multi-state, multi-organization grants with very large numbers of researchers. These grants need an overall coordinator and internal panel to ensure an organized and successfully implemented grant.

2:45 pm -- Presentation by Scott Haley - GMO Wheat and What it Means to University Breeders and End Users. The National Organization of Wheat Growers (NAWG) sees GMO wheat as the Future for wheat profitability. Yield and stress traits are a high priority. Development of new wheat varieties would shift from state institutions to private.

4:00 pm -- Marion Harris led a group discussion on the ramifications of GMO wheat. Concerns were increased seed costs to growers, GMO companies controlling how growers produce wheat under GMO contracts, and pushing out University wheat breeders and them being replaced by companies.

5:30 pm -- Adjourned

Minutes of Meeting September 22, 2010

Discussion and Oral Summaries of State Reports.

8:30 am -- WERA-066 Proposal for 2011-2016, Identification of Secretary and Location for Next Meeting. Tom Holtzer, Administrative Advisor, led the discussion on the duties of the Chair of WERA-066 and the future of WERA-066. The term for WERA-066 will soon be up for renewal. Discussions centered on member participation, communication among members, meeting dates and the overall purpose and benefits of having WERA-066 continue. After these discussions it was decided to keep the mission, enhance programming, and pursue the renewal of WERA-066. The issues challenging wheat are growing and dynamic enough that yearly meetings are a great benefit to wheat researchers.

Proposals for the next WERA-066 meeting site were solicited. Issues included the need to combine WERA meetings with other meetings whenever possible in order to be cost and time effective. October of 2011 is the start of a new year for WERA-066 but it was decided to schedule meetings in March in order to coincide with IPRI in the future. After some discussion, the members decided to have a joint meeting with the International Plant Resistance to Insects, March 2012.

Oral state Reports were mainly addressed on the first day of the meeting during speakers presentations. Written detailed reports have been submitted for each participating state. The written reports include several states where representatives were unable to attend.

10:30 am - Meeting Adjourned. A tour of the National Center for Genetic Resources Preservation facility at Ft. Collins followed.

Minutes Attachment:

Attachment

Accomplishments

[Below is a summary of reported accomplishments. Full State Reports are provided as an attachment in the minutes section.] Colorado State University A. Biological control 1. 116 species of spiders were collected from wheat production systems, and a manuscript is being drafted. 2. Results from an exclusion cage study suggest that naturally occurring biological control has increased since similar studies were conducted in the early 1990s. The study currently is being repeated for a third year. B. Plant Resistance 1. Russian wheat aphid Biotype RWA1-resistant wheat cultivars are now planted on more than 50% of Colorados wheat acreage. The pest management benefits of these varieties is unknown, although anecdotal evidence suggests that they can be noticeable. 2. Winter wheat lines with the 2414-11 (Dn7) resistance source continue to be advanced. Seed is being increased and commercial release for at least one line is anticipated. 3. An experiment to develop an economic injury level for Biotype RWA2 is being initiated using an one of the advanced 2414-11 lines. 4. Surveys were conducted to determine the presence of Dn4-virulent Russian wheat aphids. In 2009, all but one sample contained aphids virulent to Dn4. No virulence to 94M370 (Dn7) was detected. C. Biology and Management 1. Aphid flights were monitored at four locations by means of suction traps. Trap catches were higher than they have been for several years, which was reflected in widespread insecticide use. 2. Noncultivated grass hosts were surveyed in montane environments along the Cache La Poudre River for a third season. Oversummering Russian wheat aphids, as well as other cereal aphids, were found at most elevations. Russian wheat aphid biotypic diversity in these environments is being examined. 3. Insecticide treatments containing chlorpyrifos (Lorsban Advanced and Cobalt Advanced, Dow Ag Sciences), dimethoate and lambda cyhalothrin (Warrior II, Syngenta) were effective against Russian wheat aphid as well as brown wheat mite in winter wheat. Producers now have some research-based guidelines for selecting treatments for situations in which their crop is infested with both pests. 4. A foliar thiamethoxam + lambda cyhalothrin product (Endigo, Syngenta) was equal to chlorpyrifos in efficacy against Russian wheat aphid in malt barley. This is a promising alternative to lambda cyhalothrin, which has been used for several years under Section 18 registrations. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ USDA-ARS Crop Production and Pest Control Research Unit at Purdue University New approaches to resistance in wheat to Hessian fly The Hessian fly is the most important insect pest of wheat in the southeastern United States. While the use of resistant wheat is an effective means for controlling Hessian fly, it places a selective pressure on populations and has led to the appearance of genotypes of the pest that can overcome resistance. A recent evaluation of 21 of the identified resistance (R) genes in wheat to Hessian fly documented that only 5 of the R genes would provide effective protection of wheat to Hessian fly in the Southeast. These results indicate that new approaches to the deployment of R genes such as gene combinations, identification of new and effective sources of resistance, and genetically engineered resistance are needed if genetic resistance is to continue as a viable option for protection of wheat in the Southeast. Hessian fly population genetics and microsatellites We have determined that only two distinct HF populations inhabit the southeastern US and small but significant levels of gene flow occurs between them. Sequencing data and microsatellite diversity studies indicate that multiple introductions of HF occurred, rather than the previously hypothesized single introduction. In addition, it is also apparent that the most important factor studied to date relating how the populations are associated with each other appears to be directly and positively correlated with the amount of wheat planted for hay in a given area. ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Kansas State University Wheat Gene Expression is Differentially Affected by a Virulent Russian Wheat Aphid Biotype Experiments conducted to better understand the temporal expression of wheat genes controlling signaling and metabolism during compatible and incompatible D. noxia interactions revealed significant differences in level and pattern of gene expression in defense response signaling and metabolic pathways. The jasmonate (JA)-signaling genes LOX, AOS, and AOC were significantly more upregulated (~3- to 7 fold) in incompatible interactions than in compatible interactions (~2.5 to 3.5 fold) as early as 1 hr post D. noxia infestation (hpi). In contrast, glycolysis and citric acid cycle genes were expressed comparatively less (~1.5 to 2 fold) and significantly downregulated in incompatible interactions and upregulated or less downregulated in compatible interactions from 6 to 72 hpi. Differences in expression of JA-signaling genes between feeding site tissues and non-feeding site tissues suggest that D. noxia defense response signals in wheat are primarily restricted to aphid feeding sites in the initial 6 hpi. This is the first report of differential upregulation of plant genes at 1 hpi in incompatible interactions involving aphid herbivory. Early wheat plant defense responses in incompatible D. noxia interactions at 1, 3, and 6 hpi appear to be important aspects of D. noxia resistance in wheat. Reactive Oxygen Species Are Involved in Plant Defense against a Gall Midge Rapid and prolonged accumulation of H2O2 was detected in wheat plants at the attack site during incompatible interactions. Increased accumulation of both H2O2 and superoxide was detected in rice plants during non-host interactions with the larvae. No increase in accumulation of either H2O2 or superoxide was observed in wheat plants during compatible interactions. A global analysis revealed changes in the abundances of 250 wheat transcripts and 320 rice transcripts encoding proteins potentially involved in ROS homeostasis. A large number of transcripts encoded class III peroxidases that increased in abundance during both incompatible and non-host interactions, whereas the levels of these transcripts decreased in susceptible wheat during compatible interactions. The higher levels of class III peroxidase transcripts were associated with elevated enzymatic activity of peroxidases at the attack site in plants during incompatible and non-host interactions. Overall, our data indicate that class III peroxidases may play a role in ROS generation in resistant wheat and non-host rice plants during response to Hessian fly attacks. Barley Tolerance of Russian Wheat Aphid Biotype 2 Herbivory Involves Expression of Defense Response and Developmental Genes Previous phenotyping experiments revealed that plants of the barley variety Stoneham resist D. noxia damage from the Russian wheat aphid, Diuraphis noxia (Kurdjumov), via tolerance. In the present study, genes involved in upstream regulation of jasmonic acid (JA), salicylic acid (SA), ethylene (ET), auxin (AUX), and abscisic acid (ABA) biosynthetic pathways were monitored using qRT-PCR in Stoneham and susceptible Otis barley plants after D. noxia biotype 2 feeding. Results indicate that D. noxia tolerance in Stoneham plants is related to greater expression of JA-, ET-and AUX- biosynthetic pathway genes than in susceptible Otis plants, suggesting the possibility of immediate plant adjustments due to the stress of D. noxia feeding. There was limited induction of genes in the ET- (ACCS) and IAA (TDC) pathways in Stoneham tissues after D. noxia feeding. JA pathway genes upregulated in Otis tissues after D. noxia infestation failed to successfully defend Otis plants. AUX and ABA transcripts in Otis may be associated with developmental collapses resulting from source and sink adjustment failures. Interaction of Wheat Streak Mosaic Virus Infection with Wheat Resistance to Wheat Curl Mite Aceria tosichella Keifer Results of several experiments demonstrated that resistance or susceptibility of germplasm to A. tosichella is independent of initial infestation levels. A. tosichella population development and mite plant damage on wheat genotype OK05312 at 14 d post infestation were significantly lower than on susceptible Jagger plants. A. tosichella infestations and plant damage were significantly greater on WSMV-infected plants of susceptible genotypes than on corresponding uninfected plants. In A. tosichella - resistant plants, there were no statistical differences in A. tosichella infestations on healthy or WSMV - infected plants. Interactions Between Biological Control, Cultural Control and Barley Resistance to the Russian Wheat Aphid RWA populations in early-planted plots were significantly lower in all three years at the Colorado and Kansas sites. Within samples from early planting dates, RWA-resistant varieties yielded reduced RWA populations similar to those in insecticide-treated Otis plots at the Colorado and Kansas sites. Very low RWA populations were present in samples from both planting dates collected at the Nebraska site, resulting in no differences in RWA populations between varieties. Early planting dates and RWA-resistant varieties did not affect the natural occurrence of RWA biological control agents. Virus-Induced Gene Silencing of Putative Diuraphis noxia (Kurdjumov) Resistance Genes in Wheat Because of the development of virulent biotypes of the Russian wheat aphid Diuraphis noxia (Kurdjumov), the identification of new sources of barley and wheat resistance is necessary. Virus-induced gene silencing (VIGS) utilizes the plant defense system to silence viruses in inoculated plants. The accumulation of virus RNA in plants triggers the defense system to silence sequences homologous to the introduced virus and sequences of interest from a plant are inserted into the virus and silenced along with the virus. The VIGS method was tested to determine the ability of barley stripe mosaic virus (BSMV) to serve as a VIGS vector in wheat plants containing the Dnx gene for resistance to D. noxia. Dnx leaves with silenced BSMV virus yielded D. noxia populations that were significantly no different from populations produced on healthy Dnx leaves. Thus, BSMV silencing does not interfere with Dnx resistance. Several different methods were examined to determine how best to confine aphids to the silenced leaf, and a modified plastic straw cage was chosen as the optimum cage type. Microarray and gene expression data were analyzed to select two NBS-LRR type disease resistance protein genes - NBS-LRR1 and NBSLRR2 - in order to assess their role in Dnx resistance. NBS-LRR1 and NBSLRR2 were silenced by inoculating leaves of Dnx plants with barley stripe mosaic virus (BSMV) containing sequences of each gene. Controls included Dnx and Dn0 plants inoculated with BSMV and non-BSMV inoculated plants. Aphids were allowed to feed on control and treatment plants to assess aphid population and mean weight of aphids surviving at the end of the experiment. There were no differences among treatments based on aphid population, but there were significant differences the mean weights of aphids reared on several different treatments. The Gut Transcriptome of a Gall Midge, Mayetiola destructor The most striking feature of the Hessian fly larval transcriptome is the existence of a large number of transcripts coding for so-called small secretory proteins (SSP) with amino acids less than 250. Eleven of the 30 largest clusters were SSP transcripts with the largest cluster containing 11.3% of total ESTs. Transcripts coding for diverse digestive enzymes and detoxification proteins were also identified. Putative digestive enzymes included trypsins, chymotrypsins, cysteine proteases, aspartic protease, endo-oligopeptidase, aminopeptidases, carboxypeptidases, and ±-amylases. Putative detoxification proteins included cytochrome P450s, glutathione S-transferases, peroxidases, ferritins, a catalase, peroxiredoxins, and others. This study represents the first global analysis of gut transcripts from a gall midge. The identification of a large number of transcripts coding for SSPs, digestive enzymes, detoxification proteins in the Hessian fly larval gut provides a foundation for future studies on the functions of these genes. Differential Accumulation of Phytohormones in Wheat Seedlings Attacked by Avirulent and Virulent Hessian Fly (Diptera: Cecidomyiidae) Larvae We analyzed the accumulation of six phytohormones and phytohormone-related compounds in a wheat [Triticum aestivium (L.)] genotype Molly following attacks by avirulent and virulent Hessian fly [Mayetiola destructor (Say)] larvae, respectively, and examined the expression of genes in the jasmonic acid (JA) pathway by Northern blot analysis. Compared to uninfested plants, attacks by avirulent larvae resulted in increased accumulation of salicylic acid (SA) by 11.3- and 8.2-fold, 12-oxo-phytodienoic acid (OPDA) by 36.4-and 18.7-fold, 18:3 fatty acid by 4.5- and 2.2-fold, and 18:1 fatty acid by 1.8- and1.9- fold at 24- and 72-hours post initial attack (hpia), respectively, but an 20% decrease in JA accumulation at 24-hpia at the attack site. Attacks by the virulent larvae did not affect the accumulation of SA, OPDA, 18:3 and 18:1 fatty acids, but dramatically increased the concentration of auxin (AUX) from undetectable in uninfested plants to 381.7 ng/g fresh weight at 24-hpia and 71.0 ng/g fresh weight at 72-hpia in infested plants. Transcript levels of genes encoding lipoxygenase 2 (LOX2), allene oxide synthase (AOS), and Arabidopsis storage protein 2 (AtVSP2) were increased following avirulent larval attacks, but decreased following virulent larval attacks. Our results suggest that OPDA and SA may act together in wheat resistance to the Hessian fly, whereas AUX may play a role in the susceptibility of wheat plants. The increased OPDA accumulation following avirulent larval attacks was at least partially regulated through gene transcription. ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Montana State University 2010 Orange Wheat Blossom Midge In 2010, OWBM continued to present in high numbers in the Flathead Valley. Growers are becoming familiar with the pest, which has recurred in significant numbers since a massive outbreak in 2006. They have adapted to using host phenological timing to apply insecticide to minimize losses. OWBM is present in low numbers in the northeastern part of the state, with some evidence of parasitism. There is no evidence of biological control agent establishment in the Flathead Valley, although parasitoids have been released twice at multiple locations. The major wheat producing area in Montana, the Golden Triangle (apices at Great Falls, Cut Bank and Havre) was monitored using pheromone traps by County Extension Personnel. Thus far, there is no evidence of OWBM in this area. We assessed oviposition preferences using a series of RILS developed from an attractive and unattractive parent. Oviposition preference was heritable, and NILs were developed to confirm QTL. We also assessed potential attractants for ovipositing females in the field. We also assessed wheat lines incorporating Sm1 type host plant resistance that are being developed specifically for northwestern MT growing conditions. 2010 Wheat Stem Sawfly WSS continues to be a tremendous concern for Montana wheat growers. The area impacted by populations increasing in size is expanding, and many farmers are dealing with heavy damage for the first time. Populations sampled during peak flight averaged more than 15 sawflies per sweep in a series of 5 sweeps per sample. Many fields had levels of larvae-induced stem cutting (resulting in lodging) of nearly 100%. Host plant resistance, mainly in the form of solid-stemmed wheat provided variable levels of resistance under heavy pressure, with cutting ranging from 10 to over 50% in fields with stem infestation approaching 100%. Natural enemy populations, including two congeneric braconid parasitoids and a clerid predator, were present at levels up to 70% in some fields, but the overall average parasitism was approximately 20% 1. For several years, we have been researching the role of host volatiles in oviposition preference in WSS. The idea is to deploy attractive and unattractive varieties in a trap crop paradigm. This has the potential to be very effective due to the type of agriculture, available antibiosis, and behavioral characteristics of WSS. In 2010, we continued research assessing plantings of attractant solid stem 'Choteau' around unattractive 'Conan'for a total of 4 site years 2 at each of 2 sites. The control is Choteau around attractive Reeder. These are large scale plots and for each site*year we have seen a significant higher infestation in solid stem Choteau surrounding the unattractive Conan while the infestation in the interior Reeder was much greater, often equivalent to that in the peripheral Choteau. 2. Crosses between Conan and Reeder yielded a series of RIL that were tested at 2 sites for 2 years. The oviposition preferences of female wheat stem sawflies were clearly heritable. QTL associated with oviposition preference were identified and these were not correlated with any other known agronomic or host plant resistance traits. NILs were tested to confirm the role of these loci and to provide lines for testing for volatile production. 3. Investigations on varietal tolerance and the interactions between physiological yield loss, water stress and nutrient limitations indicated that the impact of WSS larval feeding on yield varied by variety. A key finding was that yield losses were much greater for nutrient limited (P) plants with sawfly-cut stems than for water and nutrient stressed uninfested plants or for water-stressed plants that were cut by the wheat stem sawfly. ^^^^^^^^^^^^^^^^^^^^^^^^^^^ North Dakota State University 2010 IPM Survey Maps from the 2010 IPM survey in North Dakota were uploaded onto the NDSU IPM website at the following address: (http://www.ag.ndsu.nodak.edu/aginfo/ndipm/) Grain aphids Aphids occurred at relatively low levels in 2010. In North Dakota the treatment threshold is when 85% of the stems have one or more aphids present prior to the completion of heading. There was little insecticide spraying for control of wheat aphids in 2010. Grasshoppers The 2010 APHIS rangeland grasshopper forecast indicated potentially heavy grasshopper infestations in many states including North Dakota. Cropland adjacent to grasshopper infested rangelands could potentially have been at risk to significant crop loss. Fortunately ample rain and periods of cool weather in the early summer delayed grasshopper emergence and slowed the development of nymphs. Few wheat fields reached the economic threshold and needed to be treated. Wheat stem maggot Maggots were counted on 100 stems per field (20 stems at 5 locations in each field). Maggots boring in the stem cause characteristic white heads. These heads fail to develop seeds, and are found in otherwise uniformly green fields. White heads were observed from late June to the end of July. Wheat maggot damage was apparent in a number of wheat fields across the state this season, however, incidence of the insect was much lower than what was seen in 2007 when 40% of the wheat fields in the state had maggot damage. Preliminary research done at North Dakota State University suggests that tank mixing insecticides (Warrior II and Baythroid XL) with the early season herbicides during 5-leaf to jointing stage helped reduce the incidence of white heads and increased yields when large numbers of wheat stem maggot adults were present. At this time no economic threshold has been developed. Cereal leaf beetle CLB is an export concern for the shipment of hay from ND to California and is monitored for state regulatory purposes. Although crop scouts found what they thought was cereal leaf beetle damage, no infestations of cereal leaf beetles were confirmed in ND in 2010. Barley thrips Thrips per stem were counted from a sample of 40 plants per field. Extension specialists observed thrips in early June in the North Central and South Central parts of the state. However, seasonal weather conditions were not conducive for barley thrips development and thrips populations never reached levels high enough to cause crop loss. Wheat stem sawfly WSS continues to be a concern for farmers in the southwestern and south-central parts of the state. Although sawfly are usually considered a problem isolated to the western part of the state, reports from numerous growers indicate that it is moving eastward across the state. The most common method for controlling sawfly is with solid stemmed varieties. Hessian fly Initiated in 2008, surveys using a five component pheromone blend have been successful in providing a great deal of valuable information. Work is also being done to: 1) Biotype a population of Hessian fly to determine the virulence status of North Dakota flies to H3, H5, H6 and H7/H8. 2) Evaluate North Dakota Hard red spring, durum and barley for resistance to Hessian fly. 3) Assess the level of virulence in the North Dakota Hessian fly population to Hessian fly resistance genes H1-H32. 4) Examine native and non-native grasses as possible hosts to Hessian fly. 5) Identify parasitic hymenoptera found attacking Hessian fly. Orange wheat blossom midge Soil samples collected in the fall of 2009 indicated increased levels of overwintering wheat midge larvae in the Northwestern and North Central parts of the state. Yet, problems did not occur because early sowing of wheat negated synchronization of wheat midge adult emergence and the vulnerable heading stage. We are only aware of a few reports of wheat midge damage, and we do not think spraying for midge control was wide spread. Additional information on the orange wheat blossom midge as well as maps of the wheat midge survey for the last 14 years are available at the following address: www.ag.ndsu.nodak.edu/aginfo/entomology/entupdates/Wheat_Midge/owbm.html) Wheat curl mite (wheat streak mosaic virus) WSMV was severe in a number of wheat fields in ND this year. The virus was confirmed in 71 wheat samples sent to the NDSU Plant Diagnostic Lab, with a majority of these samples from counties in the north central region of the state. Reasons for the high number of cases this year were last years late harvest, which made volunteer grain and weed control difficult, and abundant snow cover, which allowed for greater survival of mites and infected plants. ^^^^^^^^^^^^^^^^^^^^^^^^^^^ USDA, ARS, SPA Wheat, Peanut and Other Field Crops Research Unit Stillwater, Oklahoma A. Barley Breeding Program Eight RWA-resistant, 6-rowed, winter, feed barley germplasm lines (STARS 1006B-1013B) resistant to both greenbug and RWA will be released by the end of September, 2010. These lines are in a Post 90 background and carry the Rsg1 gene for greenbug resistance. They also have RWA resistance each from 1 of 8 different sources. A cooperative project with Texas AgriLife is ongoing to map RWA resistance genes and Rsg1 and Rsg2 greenbug resistance genes in 3 winter barley germplasm lines. B. Wheat Breeding Program The main thrust of the wheat program has continued to be the identification and purification of germplasm lines that will provide consistent and reliable differentials for the identification of newly emerging biotypes of the Russian Wheat Aphid. To further this effort, seed was requested from GRIN for: 1) seed of all of the wheat lines in the collection that were resistant to RWA1, but had no rating for RWA2 (received 79 lines), and seed of all of the wheat lines in the collection that were resistant to RWA2, but had no rating for RWA1 (received 165 lines). Screenings were conducted with the appropriate RWA1 and 2, and results are being prepared for submission back to GRIN. This year, over 50 lines that were previously identified as being resistant to RWA2 (rated 1, 2, 3, or 4) were identified as also being resistant to RWA1. Over 30 were highly resistant to RWA1. A few appear to be less resistant to RWA1 than they are to RWA2 (an unusual combination); this may be useful in biotyping work. In addition, four additional lines that were previously identified as being resistant to RWA1 are also resistant to RWA2. C. RWA Biotypic Diversity, Ecology, and Molecular Biology A new RWA biotype distribution and diversity study began this year in collaboration with researchers throughout the western United States. The last study was conducted in 2005 and covered Texas, Colorado, Oklahoma, Kansas, Nebraska, and Wyoming. The discovery of sexually reproducing RWA and extensive biotypic diversity that resulted in 2007 in western Colorado made this necessary. In this study, we hope to include states in the northwestern United States. Efforts were made to collect RWA in Oklahoma, Colorado, and New Mexico this spring but only a few samples were made because of a very unusual year of low RWA numbers. Dr. Edsel Bynum was able to make collections at 14 sites in eight High Plains counties in April. Preliminary screening for only Dn4 (Yumar) virulence indicated 96% of the samples gave an RWA1 response and 4% RWA2. Although testing will include the other RWA-resistance genes, there is a clear indication that the biotypic diversity in Texas has changed. Research on the salivary constituents of RWA continues with comparisons between RWA biotypes being conducted by Dr. Scott Nicholson, who joined the program as an ARS-Postdoc in May. Comparisons in salivary proteins between RWA1 and RWA2 using 2-D electrophoresis indicates that these two biotypes differ considerably in salivary protein composition. Research will focus on comparing RWA biotypes using Orbitrap MS analysis. Studies also include Diuraphis spp. pea aphid, and greenbug biotypes C and E. E. Molecular Ecology of Cereal Aphids and their Natural Enemies The rose-grain aphid (Metopolophium dirhodum) was collected from wheat at several locales in the Sacramento Valley of California. Sequencing of the mtDNA cytochrome oxidase subunit I (COI) gene revealed the presence of three unique haplotypes, with sequence identities of 97.9-98.6%. The frequency of haplotypes 1, 2, and 3 was 0.86, 0.07, and 0.07, respectively. This suggests that a host race especially adapted to annual grain crops may exist and is predominant in the population. However it is not yet known if there are any host associated differences in the biology of the rose-grain aphid possessing a specific haplotype. In developing experiments to ascertain if there is host adaptation associated with the three mtDNA haplotypes, we successfully established populations on Iris. Although grasses are the secondary hosts of rose-grain aphid, Iris has been reported as an occasional host. We have established colonies on, barley, wheat, and oat for host adaptation experiments. However, M. dirhodum did not colonize maize. Greenbug (Schizaphis graminum) populations and biotypes were previously found to be made up of three unique groups based on DNA sequences of mitochondrial the COI, suggesting that populations were made up of host-adapted races or possibly sub-species. Nuclear DNA (nDNA) sequences were obtained for greenbugs used in the 2000 study, plus more recently collected (2008) individuals from Oklahoma. Based on both mtDNA and nDNA data, three distinct genetic lineages were found in greenbug biotypes and populations. This supports the hypothesis that greenbug populations in the US are made up of three host races (or perhaps subspecies) that are reproductively isolated in the field. Previously it was thought that sexual reproduction between host-races occurred which led to biotypic diversity. However, the molecular genetic data do not support this hypothesis. The molecular data support the hypothesis that biotype C, or the sorghum biotype and its derivatives (E, I, and K), were the result of an independent introduction into the US during the late 1960s, and these have not interbred with the previously extant population since that time. A total of 367 aphids identified as S. graminum caught in suction traps at 9 locations in the UK during 2009 were provided by Rothamsted Research, Harpenden. DNA sequencing of the COI was performed. To date, mtDNA from 7 UK 2009 aphids were sequenced. Sequence identity ranged from 98.6 99.8% between UK and USA S. graminum. Although sequence identity was high, molecular phylogenetic analysis of UK S. graminum formed two distinct two sister clades to Clade 1, the agronomic biotypes in the USA. These are preliminary results and suggest that while UK populations are most closely related to Clade 1 greenbugs, they are significantly diverged and reproductively isolated. F. Remote sensing of cereal aphids A study was completed to determine the potential of spatial pattern metrics derived from multispectral images, in combination with topographic and edaphic variables to differentiate stress induced by RWA from other stress causing factors. Areas within fields stressed by RWA, drought, and planting and fertilization issues in six wheat fields located near Boise City, OK. A discriminant function analysis was applied to 15 variables quantifying the spatial attributes of stressed areas within the fields caused by each of the three stress factors, and topographic and edaphic variables associated with each patch. Thirteen variables were retained in the discriminant function. Overall, 97% of original patches of stress were correctly categorized. Stressed patches caused by RWA were 96.8% correctly classified, patches caused by drought were 95.8% correctly classified, and patches caused by planting and fertilization issues were 99% correctly classified. We conclude that it is possible to discriminate stress induced by RWA from other stress causing factors using multispectral imagery processed to quantitatively characterize spatial attributes of stressed areas within a field and knowledge of topographic factors related to the physical location and intensity of particular types of stress. ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Department of Entomology and Plant Pathology Oklahoma State University, Stillwater, Oklahoma Synopsis of Arthropod Pest Activity in Wheat, 2008-2010 Wheat pest pressure was variable in 2008-10. An outbreak of brown wheat mite was reported in Ellis county in March 2009, and brown wheat mite infestations were reported in April of 2010 in Ellis, Harper, Woods and Alfalfa counties. Greenbug infestations were reported in several western Oklahoma counties in 2009-2010. Army cutworms were reported in wheat and canola in Major county, spring 2010. Winter grain mites were treated in scattered locations in 2009. An outbreak of Russian wheat aphid occurred in Beaver county in 2009, with reports of scattered Russian wheat aphid infestations continuing to come from the Oklahoma Panhandle throughout the spring of 2009. Integrated Pest Management of Wheat Objectives: 1) document the distribution and impact of Hessian fly in Oklahoma winter wheat systems, (2) describe the relationship among aphids, host plants, and natural enemy biology, (3) evaluate current insect management plans for wheat production systems in Oklahoma, and (4) describe the ecology of aphidophagous natural enemies in simple and diverse wheat agroecosystems. During the 2009-2010 winter wheat growing season in Oklahoma, project investigators (1) monitored first and second generation Hessian fly abundance on susceptible, semi-resistant, and resistant wheat, and (2) monitored the effectiveness of Gaucho XT wheat seed treatment for control of first generation Hessian fly. As expected, first generation Hessian fly numbers were lowest in resistant wheat compared with susceptible cultivars. Studies were completed (see publications) describing pest and natural enemy ecology, natural enemy biology in simple and diverse wheat agroecosystems, and detection of aphid infestation with remote sensing. Data is also being summarized from a multi-year / multi-state study completed evaluating the Glance n Go sampling approach in the Southern Plains. ^^^^^^^^^^^^^^^^^^^^^^^^^^^ Texas AgriLife Extension Service Texas AgriLife Research and Extension Center, Amarillo, TX Overview of Pest Activity in Wheat, 2009-2010 Greenbug and Russian wheat aphid numbers were very low in the fall of 2009 in the Texas Panhandle. After severe winter conditions in January and February, aphids were difficult to find in fields. From March through May sporadic infestations of greenbugs, Bird Cherry- oat Aphids, and Russian wheat aphids were present in relatively low numbers in fields south of Amarillo, TX. None of the fields sampled for Russian wheat aphids North of Amarillo from March to May had any aphids (greenbugs, RWA, Bird Cherry- oat Aphids). Even with the light aphid infestation, there was a high incidence of Barley Yellow Dwarf in fields across the Texas High Plains and the Panhandle region. Infections were not extremely severe, but fields seemed to uniformly infected across the fields. A foliar insecticide trial was conducted against greenbugs in wheat. Cobalt (DowAg Sciences) provided comparable control to the standard chlorpyrifos treatment. A pyrethroid product, Declare (gama-cyhalothrin), by Cheminova was a little slower than chlorpyrifos in its control of greenbugs. A mixture of Declare with chlorpyrifos was equal to the chlorpyrifos alone and Cobalt treatments.

Publications

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Impact Statements

Improve knowledge of cereal arthropods among scientists, producers and other interested clientele.
Develop new or improved management practices for cereal arthropods.
Monitor for newly introduced pests or the development and spread of new, more damaging, biotypes.