Progress 02/25/03 to 04/06/05
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Wheat is second only to maize in the United States in terms of total area planted and production at approximately 72 million acres and 2.2 billion bushels annually. Sorghum and barley are less widely planted but are also important to U.S. agriculture. The greenbug, Schizaphis graminum, is a key pest of wheat, sorghum, and barley, while the Russian wheat aphid, Diuraphis noxia, is a key pest of wheat and barley. Widespread outbreaks of these pests occur frequently and cause losses in excess of $250 million per year. With the occurrence of greenbug biotypes that attacked sorghum in the late 1960s and the invasion of the Russian wheat aphid in 1986, coupled with the recent discovery of new U.S. Russian wheat aphid biotypes in 2003, insecticide use in wheat, sorghum, and barley increased markedly. The
low profit margins associated with production of these crops make the frequent insecticide use required to mitigate yield losses caused by cereal aphids economically unsustainable. Environmental contamination, development of insecticide-resistant pests, and human health concerns also make insecticides unappealing as a principal integrated pest management (IPM) tactic. The preventive IPM paradigm involves building pest suppressive forces into agricultural ecosystems to reduce reliance on chemical insecticides and, as a consequence, to reduce the cost of crop production and improve environmental quality and human health. Preventive IPM systems rely on a variety of biorational tactics, including insect-resistant cultivars and biological control by natural enemies, and are, by their nature, knowledge intensive. The success of preventive IPM depends on sufficient understanding of the biology, ecology, and genetics of pests and their natural enemies, their interactions with their host
plants, and their role and function in the agroecosystem to achieve a systems approach to IPM. One focus of this project is on the acquisition of the knowledge needed for effective preventive IPM centered on resistant cultivars, biological control by natural enemies, and other non-chemical IPM tactics. A second focus is on developing tools for immediate application to improve IPM practices in wheat, sorghum, and barley. In order to maximize the impact of the project, the knowledge accumulated and tools developed must be delivered to end-users in a form they can readily use. The third focus of the project is to develop an IPM Knowledge Based System by integrating the knowledge and tools developed during the project with previously existing knowledge and tools. The research to be conducted is relevant to National Program 304, Crop Protection & Quarantine, but contributes to National Program 301, Plant, Microbial & Insect Genetic Research, Genomics, & Genetic Improvement.
Accomplishments under this project contribute to the achievement of ARS Strategic Plan Goal 3, Objective 2, Performance Measure 5, in that project accomplishments contribute substantially to attainment of the Agency FY 2007 target of developing specific information and technology for producers to utilize in controlling pest outbreaks as they occur. The objectives of the project are a direct application of these program components to wheat, sorghum, and barley cropping systems. The proposed research addresses aspects of the biology, ecology, genetics, and management of cereal aphids and their natural enemies that represent critical gaps to development of environmentally and economically sound IPM programs. Attaining the project objectives will result in knowledge and tools to increase the role of natural enemies, host plant resistance, and other economical and environmentally beneficial control tactics in preventive IPM programs for the greenbug, Russian wheat aphid, and other cereal
aphids in wheat, sorghum, and barley. Incorporating new IPM knowledge and tools into computer-based decision support systems will ensure that research results are delivered to pest managers in a form they can use. 2. List the milestones (indicators of progress) from your Project Plan. Project 6217-22000-012-00D was replaced by project 6217-22000-013-00D on 4/6/05. Year 1 (FY 2004) Complete development of molecular markers for aphid parasitoids and hyperparasitoids; complete development of CE-based SSCP marker system for greenbug mtDNA haplotypes; begin examination of mtDNA sequences among greenbug parasitoid populations; complete greenbug sexual reproduction study; Initiate regional conservation buffer study; begin acquisition of multi-spectral image (SSTCRIS) data from greenbug infested wheat fields; begin incorporating new information into the Knowledge Based System (KBS) rule base. Year 2 (FY 2005) Begin acquisition of field data to develop a life system model for the greenbug
from which a natural enemy threshold for coccinellids can be derived; begin acquisition of SSTCRIS data from greenbug infested winter wheat fields; begin KBS development, incorporating information into the KBS rule base. Develop a preliminary greenbug life system model and coccinellid threshold and include it in the KBS. Establish, characterize, and sample conservation buffer plots; collect greenbugs from noncultivated grasses and crops and initiate biotype evaluations. 3a List the milestones that were scheduled to be addressed in FY 2005. For each milestone, indicate the status: fully met, substantially met, or not met. If not met, why. 1. Begin acquisition of field data to develop a life system model Milestone Substantially Met 2. Begin acquisition of SSTCRIS data from greenbug infested wheat Milestone Fully Met 3. Begin KBS development incorporating pest management information Milestone Substantially Met 4. Establish, characterize, and sample conservation buffer plots Milestone
Fully Met 5. Collect greenbugs from noncultivated grasses and crops and initiate biotype evaluations Milestone Fully Met 3b List the milestones that you expect to address over the next 3 years (FY 2006, 2007, and 2008). What do you expect to accomplish, year by year, over the next 3 years under each milestone? Project 6217-22000-012-00D was replaced by project 6217-22000-013-00D on 4/6/05. 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Developed an improved method (PCR-RFLP) to assess greenbug mtDNA variation. Action Plan component: 2.2.2.4 Determined the genetic divergence among Lysiphlebus testaceipes populations using sequencing of mtDNA and rDNA. Action Plan component: 2. 2.2.4 Demonstrated the importance of noncultivated grasses to aphid pests as temporal and apatial population reservoirs, and as a source of aphid genetic diversity. Action Plan component: 2.2.2.4 Demonstrated the utility and application of
multi-spectral remote sensing for detecting greenbug infestations in wheat fields. Action Plan component: 2.2.2.4 Established the economic importance of the Rice root aphid in winter wheat in Oklahoma. Action Plan component: 2.2.2.4 Determined the timing, location, and environmental conditions associated with the sexual cycle of the greenbug. Action Plan component: 2.2.2.4 All accomplishments made under this project are fully consistent with relevant milestones listed in the Project Plan, and with the relevant research components as defined in the National Program 304 and 301 Action Plans. Accomplishments under this project contribute to the achievement of ARS Strategic Plan Goal 3, Objective 2, Performance Measure 5, in that project accomplishments contribute substantially to attainment of the Agency FY 2007 target of developing specific information and technology for producers to utilize in controlling pest outbreaks as they occur. 7. List your most important publications in the
popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below). Royer, T.A., Giles, K.L., Elliott, N.C. Elliott. 2004. Cereal aphid expert system & the Glance 'n Go sequential sampling system for management of greenbug in winter wheat. International Congress of Entomology, August 16, 2004., Brisbane, Australia. Smith, R. 2004. New tool helps wheat farmers control greenbug. Southwestern Farm Press, November 18, 2004. Shufran, K.A., Chen, Y., Mornhinweg, D.W., Baker, C.A., Burd, J.D., Payton, T.L. 2004. Relatedness of two Russian wheat aphid biotypes from Colorado. Entomological Society of America, November 2004, Salt Lake City, Utah. Burd, J.D., Shufran, K.A., Porter, D.R. 2004. New-found virulence among North American Russian wheat aphid populations. Entomological Society of America, November 2004, Salt Lake City, Utah.
Impacts
(N/A)
Publications
- Brewer, M.J., Elliott, N.C. 2004. Biological control of cereal aphids in North America and mediating effects of host plant and habitat manipulations. Annual Review of Entomology. 49:219-242.
- Elliott, N.C., Giles, K.L., Royer, T.A., Kindler, D., Tao, F.L., Jones, D. B., Cuperus, G.W. 2003. Fixed presicion seqential sampling plans for the greenbugs and bird cherry-oat aphid (Homoptera: Aphididae) in winter wheat. Journal of Economic Entomology. 96:1585-1593.
- Kindler, D., Elliott, N.C., Giles, K.L., Royer, T.R. 2003. Economic injury level for the greenbug, schizaphis graminum, in Oklahoma winter wheat. Southwestern Entomologist. 28(3):163-166.
- Shufran, K.A. 2003. Polymerase chain reaction-restriction fragment length polymorphisms identify mtDNA haplotypes of greenbug (Hempitera: Aphididae). Journal of Kansas Entomological Society. 76(4):551-556.
- Shufran, K.A., Mayo, Z.B., Crease, T.J. 2003. Genetic changes within an aphid clone: homogenization of rDNA intergenic spacers after insecticide selection. Biological Journal of the Linnean Society. 79:101-105.
- Shufran, K.A., Weathersbee III, A.A., Jones, D.B., Elliott, N.C. 2004. Genetic similarities among geographic isolates of Lysiphlebus testaceipes (Hymenoptera: Aphidiidae) differing in cold temperature tolerances. Environmental Entomology. 33(3):776-778.
- Burd, J.D. 2004. Release and establishment of exotic parasitoids to control an invasive aphid (Diuraphis noxia) [abstract]. In: Proceedings of the 15th International Plant Protection Congress, May 11-16, 2004, Beijing, China. p. 133.
- Burd, J.D., Porter, D.R., Huang, Y. 2004. The role of non-cultivated hosts in shaping and maintaining biotypc diversity of a cereal aphid (Schizaphis graminum) [abstract]. In: Proceedings of the 15th International Plant Protection Congress, May 11-16, 2004, Beijing, China. p. 319.
- Burd, J.D., Porter, D.R., Huang, Y. 2004. Cereal aphid induced physiological modification of the host feeding site [abstract]. In: Proceedings of the 15th International Plant Protection Congress, May 11-16, 2004, Beijing, China. p. 83.
- Weathersbee, A.A., Shufran, K.A., Panchal, T., Dang, P.M and Evans. G.A. 2004. Detection and differentation of parasitoids (Hymenoptera: aphididae and aphelinidae) of the brown citrus aphid (hemiptera: aphididae): species-specific PCR amplification of 18S RDNA. Annals of the Entomological Society of America. 97:286-292.
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Progress 10/01/03 to 09/30/04
Outputs
1. What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter? Wheat is second only to maize in the United States in terms of total area planted and production, at approximately 72 million acres and 2.2 billion bushels annually. Sorghum and barley are less widely planted but are also important to U.S. agriculture. The greenbug, Schizaphis graminum, is a key pest of wheat, sorghum, and barley, while the Russian wheat aphid, Diuraphis noxia, is a key pest of wheat and barley. Widespread outbreaks of these pests occur frequently and cause losses in excess of $250 million per year. With the occurrence of greenbug biotypes that attacked sorghum in the late 1960s and the invasion of the Russian wheat aphid in 1986, coupled with the 2003 discovery of new Russian wheat aphid biotypes in the U.S., insecticide use in wheat, sorghum, and barley increased markedly. The
low profit margins associated with production of these crops make the frequent insecticide use required to mitigate yield losses caused by cereal aphids economically unsustainable. Environmental contamination, development of insecticide-resistant pests, and human health concerns also make insecticides unappealing as a principal integrated pest management (IPM) tactic. The preventive IPM paradigm involves building pest suppressive forces into agricultural ecosystems to reduce reliance on chemical insecticides and, as a consequence, to reduce the cost of crop production and improve environmental quality and human health. Preventive IPM systems rely on a variety of biorational tactics including insect-resistant cultivars and biological control by natural enemies and are, by their nature, knowledge intensive. The success of preventive IPM depends on sufficient understanding of the biology, ecology, and genetics of pests and their natural enemies, their interactions with their host
plants, and their role and function in the agroecosystem to achieve a systems approach to IPM. One focus of this project is on the acquisition of the knowledge needed for effective preventive IPM, centered on resistant cultivars, biological control by natural enemies, and other non-chemical IPM tactics. A second focus is on developing tools for immediate application to improve IPM practices in wheat, sorghum, and barley. In order to maximize the impact of the project, the knowledge accumulated and tools developed must be delivered to end-users in a form they can readily use. The third focus of the project is to develop an IPM Knowledge Based System by integrating the knowledge and tools developed during the project with previously existing knowledge and tools. This project falls within National Programs Crop Protection and Quarantine (NP 304, 70%) and Plant, Microbial, and Insect Genetic Resources, Genomics, and Genetic Improvement (NP 301, 30%). Research in NP 304 addresses
three program components: Component 2 (Biology of Pests and Natural Enemies); Component 3 (Plant, Pest, and Natural Enemy Interactions and Ecology); and Component 5 (Pest Control Technologies). Research in NP 301 addresses component 2 (Genomic Characterization and Genetic Improvement). The objectives of the project are a direct application of these program components to wheat, sorghum, and barley cropping systems. The proposed research addresses aspects of the biology, ecology, genetics, and management of cereal aphids and their natural enemies that represent critical gaps to development of environmentally and economically sound IPM programs. Attaining the project objectives will result in knowledge and tools to increase the role of natural enemies, host plant resistance, and other economical and environmentally beneficial control tactics in preventive IPM programs for the greenbug, Russian wheat aphid, and other cereal aphids in wheat, sorghum, and barley. Incorporating new IPM
knowledge and tools into computer-based decision support systems will ensure that research results are delivered to pest managers in a form they can use. 2. List the milestones (indicators of progress) from your Project Plan. The milestones listed for FY 2004 are those that were established for this interim project. Milestones listed for FY 2005 and beyond are proposed for the new project plan that has been submitted and is currently undergoing the review process. Year 1 (FY 2004) Complete development of molecular markers for aphid parasitoids and hyperparasitoids; Complete development of Capillary Electrophoresis-based SSCP marker system for greenbug mtDNA haplotypes; Begin examination of mtDNA sequences among greenbug parasitoid populations; Complete greenbug sexual reproduction study; Initiate regional conservation buffer study; Begin acquisition of multi-spectral image (SSTCRIS) data from greenbug infested wheat fields; Begin incorporating new information into the Knowledge Based
System (KBS) rule base. Year 2 (FY 2005) Continue to acquire field data for greenbug life system model and SSTCRIS imagery of greenbug infested fields; Continue development of KBS; Establish, characterize, and sample conservation buffer plots; Collect greenbugs from noncultivated grasses and crops and conduct biotype evaluations; Initiate study using PCR to quantify secondary parasitism in cereal aphids; Estimate phenotypic and genotypic variation of Russian wheat aphids. Year 3 (FY 2006) Complete acquisition of field data and begin development of greenbug life system model; Complete acquisition of SSTCRIS imagery and begin development of special-pattern extraction statistical model; Continue KBS development; Continue conservation buffer study; Complete greenbug biotype study; Genetically characterize worldwide Russian wheat aphid populations; Continue secondary parasitoid study. Year 4 (FY 2007) Complete development of greenbug life system model; Initiate field studies to validate
natural enemy threshold; Complete development of greenbug infestation spatial-pattern statistical model and begin field validation studies; Continue KBS development and initiate education program; complete conservation buffer sampling and vegetative analysis; Complete greenbug biotype evaluations and continue to analyze data; Complete greenbug hyper parasitoid study; Determine the genome size and organizational complexity of Russian wheat aphid and/or other cereal aphids. Year 5 (FY 2008) Finish field validation studies, test and refine natural enemy threshold, and test and refine statistical model to identify spatial signatures for greenbug infested fields; Interface greenbug life system model with the KBS and incorporate natural enemy threshold; Continue education program; Complete conservation buffer study; Characterize genes and/or gene products associated with Russian wheat aphid feeding and plant injury. 3. Milestones: A. List the milestones that were scheduled to be addressed
in FY 2004. How many milestones did you fully or substantially meet in FT 2004 and indicate which ones were not fully or substantially met, briefly explain why not, and your plans to do so. The milestones scheduled to be completed during Year 1 (FY 2004) are listed below. These milestones were fully or substantially met during the reporting year. Complete development of molecular markers for aphid parasitoids and hyperparasitoids: We designed, produced and tested species-specific DNA markers for the secondary parasitoids (hyperparasitoid) Alloxysta xanthopa and Dendrocerus carpenteri. These were based on the mtDNA 16S gene. The markers are PCR primers that successfully detect and differentiate the above two hyperparasitoids from their host, Lysiphlebus testaceipes (a primary parasitoid of aphids). The PCR primers also allow detection of the above species in the presence of cereal aphid host DNA, specifically greenbug, corn leaf aphid, bird cherry-oat aphid, Russian wheat aphid,
yellow sugarcane aphid, and grain aphid. A manuscript reporting this work has been written and cleared for submission to a refereed journal. Markers were not developed for Asaphes sp., Coruna sp., and Pachyneuron sp. because these genera a less common and no insect material could be obtained for them. Complete development of CE-based SSCP marker system for greenbug mtDNA haplotypes: In lieu of a CE based SSCP assay to determine greenbug mtDNA haplotype, we developed a PCR-RFLP based assay. This new assay is easier, cheaper, and faster to conduct. Also the results were more accurate at differentiating the various mtDNA greenbug haplotypes with less ambiguity. The technique for the assay was published in a peer-reviewed journal. The PCR-RFLP was used to determine mtDNA haplotype from greenbugs on crops in OK, SD, KS, NE, CO, Brazil and China. MtDNA haplotypes were also determined for greenbugs collected from non-cultivated hosts. Greenbugs parasitized by Diaretiella rapae were also
detected using the RCR-RLP assay. Begin examination of mtDNA sequences among greenbug parasitoid populations: Portions of the cytochrome oxidase I and 16S mtDNA genes of Lysiphlebus testaceipes were sequenced for isolates collected in NE, OK, TX, and FL. In a previous study, the NE population had significantly higher degree of tolerance to cold temperatures than OK and TX populations. Sequence results showed little or no sequence variation among the NE, OK and TX populations. However, the FL population showed genetic divergence from the other populations. The results were published in a peer-reviewed journal. Complete greenbug sexual reproduction study: We assessed the range the greenbug holocycle along a north-south transect ranging from North Dakota to Texas. We found that greenbugs are capable of producing oviparae and viable eggs throughout the central portion of the hard red winter wheat production area of the Great Plains. Times for peak oviparae development and peak egg
production were similar locations, indicating a general synchronization of the holocycle. Although oviparae were produced at the Brookings, SD, site, they did not survive long enough to produce eggs. At Bushland, TX, oviparae were not produced and greenbugs were able to survive parthenogenetically throughout the winter. The results from this study have been accepted for publication in two peer-reviewed journals. Initiate regional conservation buffer study: We have established field sites in Texas, Oklahoma, Kansas, Colorado, Nebraska, and Wyoming. Sampling methods have been developed and insect and plant community sampling has begun. Begin acquisition of multi-spectral image (SSTCRIS) data from greenbug infested wheat fields: One year's data were acquired from geographically widely separated wheat fields in Oklahoma on greenbug population dynamics. SSTCRIS data were acquired from an intensively sampled greenbug-infested winter wheat field in central Oklahoma for the purpose of
testing for a measurable and repeatable spectral response. Begin incorporating new information into the Knowledge Based System (KBS) rule base: The greenbug decision support system was revised by adding an improved greenbug population dynamics model and improved greenbug economic thresholds. The interface was also revised to improve the look and feel to end-users. B. List the milestones that you expect to address over the next 3 years (FY 2005, FY 2006, & FY2007). What do you expect to accomplish, year by year, over the next 3 years under each milestone? The milestones listed for FY 2005 and beyond are proposed for the new project plan that has been submitted and is currently undergoing the review process. Year 2 (FY 2005) Continue to acquire field data for greenbug life system model and SSTCRIS imagery of greenbug infested fields; continue development of KBS; Establish, characterize, and sample conservation buffer plots; collect greenbugs from noncultivated grasses and crops and
conduct biotype evaluations; initiate study using PCR to quantify secondary parasitism in cereal aphids; estimate phenotypic and genotypic variation of Russian wheat aphids. The acquisition of SSTCRIS imagery will be completed and will begin to develop a statistical model to extract the spatial pattern of altered reflectance in SSTCRIS imagery. New information will be continually incorporated (e.g., bird cherry-oat aphid economic thresholds, new guidelines for cold weather insecticide use) into the KBS rule base. Conservation buffer plots have already been established and sampling will continue. Greenbug sampling and biotypic evaluations will continue and important noncultivated grass hosts will be identified and their associated greenbug populations will be phenotyped. A method using PCR markers will be developed to identify and quantify the level of secondary parasitism of greenbugs and other cereal aphids on crops. Phenotypic and genotypic variation within and among Russian
wheat aphid biotypes in the United States will be determined. Year 3 (FY 2006) Complete acquisition of field data and begin development of greenbug life system model; complete acquisition of SSTCRIS imagery and begin development of special-pattern extraction statistical model; continue KBS development; continue conservation buffer study; complete greenbug biotype study; genetically characterize worldwide Russian wheat aphid populations; continue secondary parasitoid study. Greenbug population dynamics field studies will be completed and a variable life table model will be constructed. A statistical model to extract the spatial pattern of altered reflectance in SSTCRIS imagery will be completed, and will be field validated. The Lysiphlebus testaceipes sampling scheme will be incorporated into the KBS. On a regional scale, the relative amount of biotypic diversity (new virulence genes) among greenbug populations collected from cultivated wheat and sorghum and their associated
noncultivated grass hosts will provide a fundamental understanding of the relationship between host adapted races, biotype development, and host plant resistance. The genetic characterization of worldwide populations of the Russian wheat aphid will help to determine origin of the United States population. Year 4 (FY 2007) Complete development of greenbug life system model; Initiate field studies to validate natural enemy threshold; complete development of greenbug infestation spatial-pattern statistical model and begin field validation studies; continue KBS development and initiate education program; complete conservation buffer sampling and vegetative analysis; complete greenbug biotype evaluations and continue to analyze data; complete greenbug hyperparasitoid study; determine the genome size and organizational complexity of Russian wheat aphid and/or other cereal aphids. The refined cereal aphid population dynamics simulation models will be interfaced with the KBS and the
coccinellid natural enemy thresholds will be incorporated. The model, when completed, will be used to predict greenbug population growth over a specified time horizon, based on geographically explicit information on weather, wheat variety, and field specific details of crop management. It will be possible for a user to run several simulations and to conduct cost/benefit analyses for each. Results of simulations will be used to determine the most appropriate management action to take. Ongoing work to determine the role of conservation buffers on cereal aphids and their natural enemies will provide a better understanding of important multitrophic interactions and provide information to prescribe the most ecologically sound plant species for planting. The identification and quantification of secondary parasitism of greenbugs and other cereal aphids will be determined to better assess the impact of hyperparasitism in cereal agroecosystems. Determination of the Russian wheat aphid's
genome size and organizational complexity is the initial step needed before constructing genomic libraries, as it is essential for calculating the number of recombinants to be generated. 4. What were the most significant accomplishments this past year? A. Single most significant accomplishment during FY 2004: Detection and identification of secondary (hyper) parasitoids is time consuming and nearly impossible to accomplish by conventional means. We designed, produced, and tested species-specific DNA markers for the secondary parasitoids (hyperparasitoid) Alloxysta xanthopa and Dendrocerus carpenteri. These were based on the mtDNA 16S gene. The markers are PCR primers that successfully detect and differentiate the above two hyperparasitoids from their host, Lysiphlebus testaceipes (a primary parasitoid of aphids). The PCR primers also allow detection of the above species in the presence of cereal aphid host DNA, specifically greenbug, corn leaf aphid, bird cherry-oat aphid, Russian
wheat aphid, yellow sugarcane aphid, and grain aphid. B. Other Significant Accomplishments: There exists a need to develop effective decision support tools to help growers manage key pests of wheat such as the greenbug. At the USDA-ARS Wheat, Peanut and Other Field Crops Research Unit, Stillwater, OK, in conjunction with our collaborators (K. L. Giles and T. A. Royer, Oklahoma State University) we sought to develop internet accessible decision support software for greenbug pest management. During FY 2004 we modified the software to include a simulation model of greenbug population dynamics constructed from field data collected over several years and geographic locations, and improved the user interface by including tutorials on use of the system and other modifications intended to make the system more user friendly. The decision support system has the potential to markedly improve pest management practices for the greenbug in wheat because treatment decisions will be more
economically sound, and as a consequence more environmentally responsible. A rapid and accurate assay of greenbug genetic diversity is needed to facilitate the understanding of aphid populations and host plant associations. In lieu of a CE based SSCP assay to determine greenbug mtDNA haplotype, we developed a PCR-RFLP based assay. This new assay is easier, cheaper, and faster to conduct. Also the results were more accurate at differentiating the various mtDNA greenbug haplotypes with less ambiguity. The PCR-RFLP was used to determine mtDNA haplotype from greenbugs on crops in OK, SD, KS, NE, CO, Brazil and China. MtDNA haplotypes were also determined for greenbugs collected from non- cultivated hosts. Greenbugs parasitized by Diaretiella rapae were also detected using the RCR-RLP assay. Yield losses in winter wheat often occur in Oklahoma that cannot be attributed to known pest insect species. We established a research program to focus on relevant aspects of the biology,
ecology, and pest status of the rice root aphid. Documented through field and laboratory studies that the rice root aphid affects forage yields, and possibly grain yield, of winter wheat, and that the aphid is abundant in winter wheat fields throughout the major wheat growing regions of Oklahoma. The research will increase understanding and awareness of the pest potential of the rice root aphid in the major wheat producing state of Oklahoma. In March 2003, a new biotype (virulent population) of Russian wheat aphid that was able to injure and kill wheat containing the Dn4 resistance gene was discovered in Colorado. We collected the new biotype along with the extant population and developed clonal colonies of each population in the laboratory. Preliminary DNA sequence analysis and RAPD showed no variation within or between the two Russian wheat aphid biotypes. This suggests that the new biotype was not a new introduction (i.e. from a foreign country), but likely arose here in the
United States. C. Significant Accomplishments/Activities that Support Special Target Populations: None 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. (This is the second year for reporting on the progress of this interim project.) Developed an improved method (PCR-RFLP) to assess greenbug mtDNA variation. Action Plan component: 2.2.2.4 Determined the genetic divergence among Lysiphlebus testaceipes populations using sequencing of mtDNA and rDNA. Action Plan component: 2. 2.2.4 Demonstrated the importance of noncultivated grasses to aphid pests as temporal and apatial population reservoirs, and as a source of aphid genetic diversity. Action Plan component: 2.2.2.4 Demonstrated the utility and application of multi-spectral remote sensing for detecting greenbug infestations in wheat fields. Action Plan component: 2.2.2.4 Established the economic importance of the Rice root aphid in winter wheat in Oklahoma. Action Plan
component: 2.2.2.4 Determined the timing, location, and environmental conditions associated with the sexual cycle of the greenbug. Action Plan component: 2.2.2.4 6. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? A web-based greenbug pest management decision support system was made available in the public domain. The decision support system is available for use now. The primary constraint to adoption is educating end-users on how to use the system and its advantages over current pest management decision-making approaches. 7. List your most important publications in the popular press and presentations to organizations and articles written about your work. Pons, Luis. 2004. Germplasms from previous study may thwart new aphid biotype. Agricultural
Research, USDA-ARS, April 2004, pp. 16-18. Royer, T.A., Giles, K.L., and Elliott, N.C. 2004. The Cereal aphid expert system and Glance-N-Go Sampling, questions and answers. CR-7191. Oklahoma Cooperative Extension Service, Stillwater, OK. Royer, T.A., Giles, K.L., and Elliott, N.C. 2004. Common insect and mite pests of small grains. F-7176. Oklahoma Cooperative Extension Service, Stillwater, OK. Burd, J.D. 2004. Biology and Ecology of the Russian wheat aphid. International Plant Resistance Workshop, Baton Rouge, LA. Kindler, S.D. 2004. Update on the rice root aphid in Oklahoma. Oklahoma Wheat Commission and Oklahoma Grain Sorghum Commission. Shufran, K.A. 2004. Relatedness of two Russian wheat aphid Biotypes from Colorado: Preliminary Data. International Plant Resistance Workshop, Baton Rouge, LA.
Impacts
(N/A)
Publications
- Burd, J.D., Porter, D.R., Huang, Y. 2004. Cereal aphid induced physiological modification of the host feeding site [abstract]. In: Proceedings of the 15th International Plant Protection Congress, May 11-16, 2004, Beijing, China. p. 83.
- Weathersbee, A.A., Shufran, K.A., Panchal, T., Dang, P.M and Evans. G.A. 2004. Detection and differentation of parasitoids (Hymenoptera: aphididae and aphelinidae) of the brown citrus aphid (hemiptera: aphididae): species-specific PCR amplification of 18S RDNA. Annals of the Entomological Society of America. 97:286-292.
- Burd, J.D. 2004. Release and establishment of exotic parasitoids to control an invasive aphid (Diuraphis noxia) [abstract]. In: Proceedings of the 15th International Plant Protection Congress, May 11-16, 2004, Beijing, China. p. 133.
- Burd, J.D., Porter, D.R., Huang, Y. 2004. The role of non-cultivated hosts in shaping and maintaining biotypc diversity of a cereal aphid (Schizaphis graminum) [abstract]. In: Proceedings of the 15th International Plant Protection Congress, May 11-16, 2004, Beijing, China. p. 319.
- Brewer, M.J., Elliott, N.C. 2004. Biological control of cereal aphids in North America and mediating effects of host plant and habitat manipulations. Annual Review of Entomology. 49:219-242.
- Elliott, N.C., Giles, K.L., Royer, T.A., Kindler, D., Tao, F.L., Jones, D. B., Cuperus, G.W. 2003. Fixed presicion seqential sampling plans for the greenbugs and bird cherry-oat aphid (Homoptera: Aphididae) in winter wheat. Journal of Economic Entomology. 96:1585-1593.
- Kindler, D., Elliott, N.C., Giles, K.L., Royer, T.R. 2003. Economic injury level for the greenbug, schizaphis graminum, in Oklahoma winter wheat. Southwestern Entomologist. 28(3):163-166.
- Shufran, K.A. 2003. Polymerase chain reaction-restriction fragment length polymorphisms identify mtDNA haplotypes of greenbug (Hempitera: Aphididae). Journal of Kansas Entomological Society. 76(4):551-556.
- Shufran, K.A., Mayo, Z.B., Crease, T.J. 2003. Genetic changes within an aphid clone: homogenization of rDNA intergenic spacers after insecticide selection. Biological Journal of the Linnean Society. 79:101-105.
- Shufran, K.A., Weathersbee III, A.A., Jones, D.B., Elliott, N.C. 2004. Genetic similarities among geographic isolates of Lysiphlebus testaceipes (Hymenoptera: Aphidiidae) differing in cold temperature tolerances. Environmental Entomology. 33(3):776-778.
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Progress 10/01/02 to 09/30/03
Outputs
1. What major problem or issue is being resolved and how are you resolving it? Wheat is second only to maize in the United States in terms of total area planted and production at approximately 72 million acres and 2.2 billion bushels annually. Sorghum and barley are less widely planted, but are also important to U.S. agriculture. The greenbug is a key pest of wheat, sorghum, and barley, while the Russian wheat aphid, Diuraphis noxia, is a key pest of wheat and barley. Widespread outbreaks of these pests occur frequently and cause losses in excess of $250 million per year. With the occurrence of greenbug biotypes that attacked sorghum in the late 1960s and the invasion of the Russian wheat aphid in 1986, insecticide use in wheat, sorghum, and barley increased markedly. The low profit margins associated with production of these crops make the frequent insecticide use required to mitigate yield losses caused by cereal aphids economically unsustainable.
Environmental contamination, development of insecticide-resistant pests, and human health concerns also make insecticides unappealing as a principal IPM tactic. The preventive IPM paradigm involves building pest suppressive forces into agricultural ecosystems to reduce reliance on chemical insecticides and, as a consequence, to reduce the cost of crop production and improve environmental quality and human health. Preventive IPM systems rely on a variety of biorational tactics including insect-resistant cultivars and biological control by natural enemies and, are by their nature, knowledge intensive. The success of preventive IPM depends on sufficient understanding of the biology, ecology, and genetics of pests and their natural enemies, their interactions with their host plants, and their role and function in the agroecosystem to achieve a systems approach to IPM. One focus of this project is on the acquisition of the knowledge needed for effective preventive IPM centered on
resistant cultivars, biological control by natural enemies, and other non-chemical IPM tactics. A second focus is on developing tools for immediate application to improve IPM practices in wheat, sorghum, and barley. In order to maximize the impact of the project, the knowledge accumulated and tools developed must be delivered to end-users in a form they can readily use. The third focus of the project is to develop an IPM KBS integrating the knowledge and tools developed during the project with previously existing knowledge and tools. 2. How serious is the problem? Why does it matter? The severe damage to wheat, sorghum, and barley caused by the feeding activities of the greenbug and Russian wheat aphid, and by disease transmission by several cereal aphids, combined with the abundance of these pests, make cereal aphids the most important insect pests of wheat, sorghum, and barley in much of the Great Plains. Greenbug, Russian wheat aphid, and other cereal aphid outbreaks occur
somewhere in the region every year. Economic losses caused by cereal aphids exceed $100 million per year in the region, and are considerably greater during severe outbreaks, which occur every 5-10 years. These losses present a threat to the economic viability of wheat, sorghum, and barley production. Improved IPM systems for these pests are badly needed and would greatly reduce monetary losses caused by them. Several of the cheapest and most effective chemical insecticides used for controlling cereal aphids are expected to be prohibited for use by the EPA in the near future, further increasing the need for control alternatives. The research is important to grain producers, crop consultants, private enterprise, and all other persons and organizations involved in pest management in wheat, barley, and sorghum. The potential impact of the research cannot be stated with certainty, but based on the extent of monetary losses to wheat, barley, and sorghum producers to pest aphids even
incremental improvements in pest management programs would have high economic pay-off. As an example, we previously estimated the economic value of a decision support system we are developing for greenbug management in wheat at $7.1 to $10.7 million annually. 3. How does it relate to the National Program(s) and National Program Component(s) to which it has been assigned? This project has been assigned to National Programs 304 (70%) and 301 (30%). Research in NP 304 addresses three program components: Component 2 (Biology of Pests and Natural Enemies); Component 3 (Plant, Pest, and Natural Enemy Interactions and Ecology); and Component 5 (Pest Control Technologies). Research in NP 301 addresses component 2 (Genomic Characterization and Genetic Improvement). The objectives of the project are a direct application of these program components to wheat, sorghum, and barley cropping systems. Specifically, our research will result in new knowledge of the biology, ecology, and genetics of
cereal aphids and their natural enemies; improved pest and natural enemy population sampling methods; molecular probes for cereal aphid parasitoids to track the fate of introduced biocontrol agents and to aid in understanding the ecology and conservation of endemic natural enemies; DNA fingerprinting tools to differentiate various species and strains of parasitic micro- wasps within cereal aphids and cereal aphid remains within the guts of arthropod predators; and knowledge-based systems for IPM decision-making. Various research objectives are being conducted in cooperation with scientists in other research projects within the research unit, and researchers at Oklahoma State University, Texas AM University, Colorado State University, University of Nebraska, Alderson Broaddus College, and SST Development Group, Inc. 4. What were the most significant accomplishments this past year? A. Single Most Significant Accomplishment during FY 2003: Research on the genetics of greenbug-host
associations has previously relied upon expensive and time-consuming DNA sequencing and phylogenetic analysis. At the USDA-ARS Wheat, Peanut, and Other Field Crops Research Unit, Stillwater, OK, we developed an improved method (PCR-RFLP) to assess greenbug mtDNA variation. This year he showed that individual aphids could be identified to a sub-specific clade in less than 24 hours, without the need for time consuming and expensive DNA sequencing, and complicated phylogenetic analysis. The technique is significant because it will provide a time and cost efficient tool for the study of the genetics of greenbug-host associations that can probably be adapted to study hundreds (if not thousands) of aphids from the US and other countries. B. Other Significant Accomplishments: Recently, the importance of non-cultivated grasses to aphid pests as temporal and spatial population reservoirs, and as a wellspring of genetic diversity has been demonstrated. At the USDA-ARS Wheat, Peanut, and
Other Field Crops Research Unit, Stillwater, OK, we conducted research in collaboration with the USDA Natural Resources Conservation Service to determine the role of Conservation Buffers on cereal insect pests and their natural enemies. This year we established and sampled research sites near USDA-NRCS field stations at El Dorado, Hayes, and Marysville, KS, Springfield and Akron, CO, and at Cheyenne, WY, with additional sites were located at Chickasha, OK, and Amarillo and Dumas, TX. Information from this research will be used to improve pest management strategies and to develop site-specific recommendations for plant species to be used in the USDA-NRCS CORE 4: Conservation Practices Reference Manual. C. Significant Accomplishments/Activities that Support Special Target Populations: None 5. Describe the major accomplishments over the life of the project, including their predicted or actual impact. Several of the objectives of this project are built upon objectives of project
6217-22000-011-00D, which recently terminated. Objectives from the previous project that are being expanded upon in the current project contribute to NP 301, Component 2 (Genomic Characterization and Genetic Improvement) and NP 304, Components 2 (Biology of Pests and Natural Enemies) and 3 (Plant, Pest, and Natural Enemy Interactions and Ecology). Several accomplishments from the previous project filled critical gaps to the development of environmentally and economically sound IPM programs for cereal aphids in wheat, sorghum, and barley. For example: 1) DNA fingerprinting tools for minute parasitoids and cereal aphids were developed and shown to be valuable for assessing host and prey relationships for natural enemies of cereal aphids in the field; 2) Cost- effective sampling methods and economic thresholds were developed to determine populations of pest aphids in wheat fields, which have immediate application for improved economic and environmentally sound cereal aphid IPM; and 3)
A body of knowledge was developed on how cultural practices within agricultural fields and ecological heterogeneity within agricultural landscapes affect populations of cereal aphid natural enemies, which has long-term application for conserving and enhancing the effectiveness of natural enemies in cereal aphid IPM. Because this project is new, having been initiated and approved during FY 2003, there are no major accomplishments over the life of the project to add to those from the previous project, apart from accomplishments listed under question 4. 6. What do you expect to accomplish, year by year, over the next 3 years? FY2004: Complete development of molecular markers for the parasitoid L. testaceipes, and the hyperparasitoids Dendrocus carpenteri, Alloxysta sp., Asaphes sp., Coruna sp. and Pachyneuron sp. Also, develop species- specific markers for the common cereal aphids found in the Great Plains, i.e., the greenbug, bird cherry-oat aphid, and corn leaf aphid (Rhopalosiphum
maidis). Analyze data from continuing greenbug sexual reproduction studies; and optimize techniques for the induction of the greenbug holocycle and successful egg hatch. Continue regional conservation buffer study and greenbug population dynamics field studies. Begin acquisition of multi-spectral data from greenbug infested winter wheat fields for the purpose of testing for a measurable and repeatable spectral response of infestations. Complete the development of the CE- based SSCP marker system for determining greenbug mtDNA haplotypes. Complete mtDNA analysis of OK, NE, and TX L. testaceipes populations. Collect L. testaceipes populations from numerous geographic locations and host aphids. Begin to examine mtDNA sequences among populations. Develop techniques for stylectomy and phloem exudate collection. Develop capillary electrophoresis methods. Incorporate new information (e.g., improved greenbug economic thresholds and forage thresholds) into the rule base of a previously
developed pest management decision support system. FY2005: Develop rearing methods for hyperparasitoids and establish colonies of D. carpenteria and Alloxysta. Initiate laboratory in vivo studies to detect the presence of primary and hyperparasitoids in cereal aphids. Complete acquisition of multi-spectral imagery and begin to develop a statistical model to extract the spatial pattern of altered reflectance in multi- spectral imagery. Complete greenbug collections on eastern and western U. S. Coasts. Begin to determine mtDNA haplotypes of individual greenbugs from these collections. Complete host suitability and developmental studies of L. testaceipes from OK and FL. Continue to collect L. testaceipes populations from numerous geographic locations and aphid hosts and sequence mtDNA genes. Examine molecular systematics of above host/location/parasitoid combinations. Initiate collection, analysis, and characterization of phloem exudates from resistant and susceptible aphid hosts.
Continue to incorporate new information (e.g., bird cherry-oat aphid economic thresholds, new guidelines for cold weather insecticide use) into the pest management decision support system rule base. FY2006: Complete greenbug population dynamics field studies and construct a variable life table model. Complete development and testing of a sequential sampling scheme for L. testaceipes. Complete laboratory in vivo studies to detect hyperparasitism. Begin collections to detect and estimate populations of D. carpenteria and Alloxysta in field populations of L. testaceipes. Complete development of a statistical model to extract the spatial pattern of altered reflectance in multi-spectral imagery, and acquire field data to validate the model. Complete determinations of mtDNA haplotypes of individual greenbugs. Continue to collect L. testaceipes populations from numerous geographic locations and aphid hosts and sequence mtDNA genes. Examine molecular systematics of above Conduct artificial
diet studies. Incorporate the L. testaceipes sampling scheme into the pest management decision support system. 7. What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end- user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products? Site-specific recommendations and guidelines for plant species that will advance pest management strategies for conservation buffers are being incorporated into the USDA-NRCS Core 4: Conservation Practices Reference Manual. Adaptation of this technology by farmers should be rapid, and there are no known constraints to its use or durability. Following up on last year's release of Glance 'n Go sampling for greenbugs and the greenbug expert system, training materials were developed and assembled this year for greenbug Glance 'n Go Sampling and the greenbug expert system. These materials were
developed in conjunction with our collaborators (Tom Royer and Kris Giles, Department of Entomology and Plant Pathology, Oklahoma State University). The materials consist of Power Point lectures and script, a training packet including all materials needed to administer training, additional resource materials, and a CD with the expert system and Power Point lectures. The purpose of the training materials is to make it easy for our target audience, county extension agents and other educators, to deliver training on the use of Glance 'n Go Sampling and the Greenbug expert system to growers, crop consultants, and other pest management practitioners, and thereby speed the rate of adoption of the tools. 8. List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: This does not replace your peer-reviewed publications listed below). Wilde, G. State report on insect conditions. Annual Fall Cereal Conference,
Kansas State University, Manhattan. 2003.
Impacts
(N/A)
Publications
- JONES, D.B., GILES, K.L., BERBERET, R.C., ROYER, T.A., ELLIOTT, N.C., PAYTON, M.E. FUNCTIONAL RESPONSES OF AN INTRODUCED PARASITOID AND AN INDIGENOUS PARASITOID ON GREENBUG AT FOUR TEMPERATURES. ENVIRONMENTAL ENTOMOLOGY. 2003. V. 32. P. 425.432.
- GILES, K.L., JONES, D.B., ROYER, T.A., ELLIOTT, N.C., KINDLER, D. DEVELOPMENT OF A SAMPLING PLAN IN WINTER WHEAT THAT ESTIMATES CEREAL APHID PARASITISM LEVELS AND PREDICTS POPULATION SUPPRESSION. JOURNAL OF ECONOMIC ENTOMOLOGY. 2003. V. 96(3). P. 975-982.
- ELLIOTT, N.C., GILES, K.L., ROYER, T.A., KINDLER, D., JONES, D.B., TAO, F. L. THE NEGATIVE BINOMIAL DISTRIBUTION AS A MODEL FOR DESCRIBING COUNTS OF GREENBUGS, SCHIZAPHIS GRAMINUM, ON WHEAT. SOUTHWESTERN ENTOMOLOGIST. 2003. V. 23(2). P. 131-136.
- GREENSTONE, M.H., SHUFRAN, K.A. SPIDER PREDATION: SPECIES-SPECIFIC IDENTIFICATION OF GUT CONTENTS BY POLYMERASE CHAIN REACTION. JOURNAL OF ARACHNOLOGY. 2003. V. 31. P. 131-134.
- SHUFRAN, K.A., MAYO, Z.B., CREASE, T.J. GENETIC CHANGES WITHING AN APHID CLONE: HOMOGENIZATION OF RDNA INTERGENIC SPACERS AFTER INSECTICIDE SELECTION. BIOLOGICAL JOURNAL OF THE LINNAENAN SOCIETY, LONDON. 2003. V. 79. P. 101-105.
- ANSTEAD, J.A., BURD, J.D., SHUFRAN, K.A. OVER-SUMMERING AND BIOTYPIC DIVERSITY OF SCHIZAPHIS GRAMINUM (HOMOPTERA: APHIDIDAE) POPULATIONS ON NONCULTIVATED GRASS HOSTS. ENVIRONMENTAL ENTOMOLOGY. 2003. V. 32(3). P. 662-667.
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