| Title |
Investigators | Department | Objectives | Approach Keywords | Progress Reports | Impact Statements | Publications | |
Project * COL00646 | |
| Title | Biology and Management of the Russian Wheat Aphid, Diuraphis Noxia (Mordvilko), in Colorado |
| Investigator(s) | Peairs, FB; Haley, SD; Johnson, JJ; Holtzer, TO; |
| Department | Bioagricultural Sciences and Pest Mgmt. |
| Objectives | 1) Refine economic injury levels and thresholds for Russian wheat aphid in small grains to incorporate additional factors such as variety, cropping system, and presence of other pests. Monitor economic impact of Russian wheat aphid in Colorado. 2) Categorize the mechanisms of known genetic sources of resistance in wheat to Russian wheat aphid in order to determine the best combinations for stable resistance. 3)Describe the biotypic diversity of Russian wheat aphid in Colorado. Survey wheat production systems for economically significant biotypes. 4) Using both greenhouse and multiple field testing environments, develop and evaluate experimental wheat and barley lines and cultivars that combine high and stable yield and end-use quality with resistance to the Russian wheat aphid. 5) Seek ways to improve management of Russian wheat aphid through the use of diversified dryland cropping systems. 6) Improve application technology including safer and more effective insecticides and more efficient application techniques. |
| Approach | Refine economic injury levels for Russian wheat aphid in small grains to incorporate factors such as variety, cropping system, and other pests. Monitor economic impact of Russian wheat aphid in Colorado. Different Russian wheat aphid densities will be established by infestation with greenhouse-reared aphids. Resulting yield and quality losses will be compared for susceptible wheats and for resistant wheats varying in source of resistance. Similar procedures will be used to evaluate the influence of factors that affect the yield loss relationship, e.g., other pests, biotype or modified crop management. Economic impact will be monitored with information provided by the National Agricultural Statistics Service. Estimates will be compared to aphid flight activity. Categorize the mechanisms (antibiosis, antixenosis, or tolerance)of known genetic sources of resistance to economically significant Russian wheat aphid biotypes to determine combinations for stable resistance. Russian wheat aphid behavior, fecundity, reproductive rates, survival, and plant damage will be determined for resistance genes in adapted wheat backgrounds. Describe the biotypic diversity of Russian wheat aphid in Colorado. Survey wheat production systems for economically significant biotypes. Russian wheat aphids will be collected from wheat and barley crops and alternate host grasses (Armstrong et al. 1991). Samples initially will be screened with 4 differentials (Yuma, Yumar [(Dn4], 94M370 [Dn7], and 2414-11). Potentially new biotypes will be rescreened with 20 differentials. The use of biotype-specific molecular markers for surveys will be evaluated. Using both greenhouse and multiple field testing environments, develop and evaluate experimental wheat and barley lines and cultivars that combine high and stable yield and end-use quality with resistance to the Russian wheat aphid. Yield, yield stability, agronomic adaptation, end-use quality, and Russian wheat aphid resistance will be evaluated in replicated, multi-locational and multi-year trials in eastern Colorado. Seek ways to improve management of Russian wheat aphid through the use of diversified dryland cropping systems. Long-term dryland cropping system studies have been established at three locations in eastern Colorado. Each location is planted to locally profitable crop rotations. Standard weather, crop, soil and water data are collected. Crop rotations vary by location, but all locations have rotations that include susceptible and Russian wheat aphid-resistant cultivars. Aphids and their natural enemies are monitored throughout the growing season. Other pests are evaluated if they exceed currently accepted action thresholds. Improve application technology including safer and more effective insecticides and more efficient application techniques. Use replicated tests to compared the efficacy of new, safer insecticides with that of commercial standards for control of Russian wheat aphid in winter wheat and irrigated spring barley. Use similar methods to evaluate new application technology, such as seed treatments. Yield comparisons will be made when appropriate. |
| Keywords | Russian wheat aphid, winter wheat, plant resistance, biotypes, diversified dryland cropping systems, economic injury levels, insecticides, integrated pest management |
| Progress Reports | |
| 1993 | For a second season Russian wheat aphid damage potential on a resistant variety was compared to that of a susceptible variety. Economic response to insecticides on both varieties also was measured at 3 locations. This information will allow producers to assess the significance of infestations in resistant varieties once they are released and widely grown. Initial observations were made on the effect of increased cropping system diversity on Russian wheat aphid and its natural enemies were made at two locations. These studies are intended to find ways of enhancing biological control of Russian wheat aphid and to determine how the aphid might respond to the intensified dryland cropping systems likely to be adopted by Colorado producers. A final year of observations were made on the effect of planting date on Russian wheat aphid in eastern Colorado. Similar experiments also have been developed for western and southwestern parts of the state. The agronomic, entomological and plant disease information derived from this study will allow Colorado wheat producers to make more informed planting date decisions. |
| 1994 | The new cultivar 'HALT' was released to wheat seed producers in 1994. 'Halt' has excellent RWA resistance, is 5 percent lower yielding than 'TAM107' (based on testing in 20 environments), the predominant cultivar in Colorado, has excellent breadmaking quality, and is similar to 'TAM107' in most other traits. A 'Halt' sister line with and without Russian wheat aphid infestation yielded 61 and 63 bushels per acre, respectivley, while uninfested and infested 'TAM107' yielded 71 and 39, respectively. Insecticide use by producers would not have been necessary on the resistant line under these conditions of severe infestation.. Russian wheat aphids were held under caged and uncaged conditions in a wheat-fallow system to determine the effect of commercially available convergent lady beetles and green lacewings (biological control organisms) that had been released nearby. In this study, biological control had no effect on the Russian wheat aphid population increases. Imidacloprid seed treatments on spring malting barley were equal or superior to other insecticide options for a fourth year. When registered, this product will provide an effective and relatively safe means of RWA chemical control that will be highly desirable in some of the more urbanized barley production areas along the Front Range. |
| 1995 | Russian wheat aphid (RWA) remains the major insect pest of wheat and barley in Colorado. Colorado small grains producers benefit from having a low cost, environmentally sound RWA management strategy based on resistant cultivars and enhanced by biological control and modified cultural practices. Objective 1. RWA economic thresholds were compared on susceptible and resistant cultivars at 4 locations. Treatment was not needed on the resistant cultivar. Statewide losses to RWA were negligible due to unusually cool, wet growing conditions. Objective 2. Three resistance genes have been backcrossed into cultivars and breeding lines. Lines with gene combinations have also been developed. Objective 3. RWA resistance has been characterized (tolerance, mild antibiosis) in 'Halt' at two growth stages. Objective 4. Resistant versions of cultivars commonly grown in Colorado are being tested at several locations. Objective 5. RWA alates were again monitored with suction traps at 7 locations. Objective 6. The effects of row spacing and grazing on RWA densities were tested for a 4th year but RWA abundance was too low for meaningful observations. Objective 7. More RWA natural enemies were collected from a diverse cropping system compared to wheat-fallow. Establishment of natural enemies was not successful in either system. Commercial biological controls did not reduce RWA for a 2nd year in on-farm studies. Objective 8. No registered or experimental insecticide performed better than current commercial standards. |
| 1996 | Obj 1. Action thresholds on 3 commercial wheats and their resistant (Dn4) counterparts are being compared. Obj 2. RWA overwintered less on 'Halt' wheat than on 'TAM 107'. RWA oversummered on Canada wildrye through mid-August, about the time when the first wheat is sown in the area. Obj 3. Both RWA and army cutworm were significantly reduced by spring grazing of winter wheat. Obj 4. No progress. Obj 5. 8 insecticide treatments were not superior to labeled treatments. Imidacloprid seed treatments failed to control RWA in 3 commercial barley fields. Obj 6. Backcross-derived resistant Yuma, Lamar, and TAM 107 wheats are in advanced yield tests for probable release in 1997. Multiple resistance lines are in preliminary yield tests. Pyramided resistance lines are in 2nd backcross with adapted wheat cultivars. Efforts continue to incorporate RWA resistance from rye and goatgrass crosses. In our 1st field screening, 7500 F5 lines were artificially infested with greenhouse-reared RWA in the spring of 1996. Uniform aphid damage allowed discard of susceptible lines. Obj 7. Resistance to RWA in 'Halt' has been categorized as mostly tolerance at 4 growth stages. Obj 8. On-farm yields of 'Halt' and 'TAM 107' were compared at 17 locations in the absence of significant RWA infestations. 'Halt' yields and test weights were 2.4 and 1.0% lower than 'TAM 107', respectively. Excluding the 3 extremely dry locations, 'Halt' yielded 0.9% more than 'TAM 107' indicating no yield penalty for the resistant cultivar. |
| 1997 | Russian wheat aphid remains the most significant pest of small grains in Colorado. An estimated 750,000 acres were treated for this problem during the 1997 crop year. Current research emphasizes plant resistance and Russian wheat aphid management within the larger context of dryland cropping systems. Obj 1. Experiments comparing action thresholds on 3 commercial wheats and their resistant (Dn4) counterparts were harvested at 3 locations and data are being analyzed. Similar experiments comparing the action thresholds for 3 similar wheats containing 3 different resistance genes have been established. Obj 2. A tenth year of monitoring flights with suction traps was completed. A report synthesizing the observations from this project has been drafted and should be available in 1998. Obj 3. RWA was significantly reduced by spring grazing. Russian wheat aphid natural enemies were also affected by this cultural practice. In a separate grazing study in southeast Colorado, fall grazing and spring grazing were equally effective in reducing RWA densities. Grazing did not affect resistance in Halt. Obj 4. Cropping system studies were established at Lamar (wheat, sorghum, grazing), Akron (wheat, corn, millet, sunflower), and northwest Weld County (wheat, millet, sunflower). Wheat in each of these studies includes both RWA-resistant and susceptible cultivars. Spiders were monitored in RWA-resistant Halt and susceptible TAM 107 in cooperation with USDA-ARS scientists from Stillwater, OK. Obj 5. 7 insecticide treatments were not superior to commercial standards. Imidacloprid seed treatments failed to control RWA in a replicated small plot barley test. Imidacloprid was not superior to Dn4-based resistance in controlling RWA in southeast Colorado. Obj 6. The RWA-resistant wheats, Yumar and Prowers were approved for release. Resistant versions of TAM 107 and Akron are in advanced stages of development. Multiple resistance lines are in preliminary yield tests. Field screening of the F5 nursery was again successful, although there is a need for increased aphid rearing capacity and perhaps improved efficiency in field infestation methods. Obj 7. Resistance to RWA in Halt has been categorized as mostly tolerance at 4 growth stages. Low levels of antibiosis and antixenosis were also observed. Progress in this objective has been hampered by problems with controlled environment facilities. Obj 8. Halt outyielded TAM 107 in 9 of 17 on-farm tests and differences were substantial in locations where RWA infestations were heavy and untreated. Differences in yield were small in the instances where TAM 107 outyielded Halt. Russian wheat aphid resistant wheats are a viable management approach. Insecticide use does not seem necessary on resistant cultivars, resulting in substantial economic and environmental benefit. Use of resistant cultivars in intensified dryland crop rotations could result in a more productive and stable production system. |
| 1998 | Russian wheat aphid remains the most significant pest of small grains in Colorado. Economic impact varies from year to year, with 1997 - 1998 having the least aphid activity since this pest entered the state in 1986. Current research emphasizes plant resistance and Russian wheat aphid management within the larger context of dryland cropping systems. An eleventh year of monitoring flights with suction traps was completed. A report synthesizing the observations from this project has been reviewed and is in final stages of publication. The suction trap data provide a long-term record of Russian wheat aphid activity in the state. Pest and beneficial insect monitoring was initiated at each cropping system study location (Lamar, Akron, Nunn). Integrated pest management of Russian wheat aphid relies on the key strategy of resistant wheats. To be effective this approach must be successful in a stressful dryland agroecosystem. These experiments have been implemented to evaluate this IPM system. To be as realistic as possible, two of these are located in growers fields, have been designed with grower input and are managed jointly with the grower-cooperator. Data are collected not only on crop and system performance, but also on the overall influence of cropping system design on pests and biological control agents. No experimental insecticide treatment was superior to commercial standards used in winter wheat. Lambda-cyhalothrin was identified as a promising substitute for chlorpyrifos in malting barley. Barley producers have been without a safe and effective insecticide for RWA management. Experiments comparing the economic injury levels for 3 similar wheats containing 3 different resistance genes have been established for a second year at 3 locations. The results of these experiments provide guidance on developing management guidelines for new aphid-resistant wheats as they are released to growers. The RWA-resistant wheat, Prairie Red (a resistant version of TAM 107), was approved for release. A resistant versions of Akron is in advanced stages of development. Aphid rearing capacity has been substantially increased with the intent of moving more screening activity to the field to allow testing of more plants. RWA-resistant barleys at various stages of development were tested under artificial infestation at Fort Collins, in cooperation with ARS and industry researchers. Effective resistance is available in both wheat and barley. The use of resistant cultivars will be the central Russian wheat aphid management strategy. Russian wheat aphid activity was negligible this season, allowing for on-farm comparisons of resistant and susceptible wheats in the absence of damage. This provides a good measure of the risk to the grower of planting a resistant wheat. The performance of resistant Halt and Yumar was similar to the susceptible standard TAM 107. Planting resistance wheats provides effective, low cost insurance against the cost of treating for Russian wheat aphid. |
| 1999 | Russian wheat aphid remains the most significant pest of small grains in Colorado. Economic impact varies from year to year, with 1998 - 1999 having significant aphid activity, although it was offset by unusually favorable production conditions. Current research emphasizes plant resistance and Russian wheat aphid management within the larger context of dryland cropping systems. An eleventh year of monitoring flights with suction traps was completed. A report synthesizing the observations was published. The suction trap data provide a long-term record of Russian wheat aphid activity in the state. In on-farm tests, expression of Dn4-based resistance to Russian wheat aphid in several cultivars varied with genetic background. Data from aphid-resistant cultivar economic injury level studies were used to estimate the economic benefits of planting these wheats under worst-case infestation conditions. A realistic definition of aphid resistance was then developed for distribution with certified seed. Resistant barleys from USDA-ARS and industry continue to perform well under artificial infestation at ARDEC. Resistance also was effective in several on-farm tests, although the experimental lines were not acceptable in terms of yield and quality. Pest and beneficial insect monitoring was continued at two cropping system study locations (Lamar and Akron). Sampling and monitoring methodology is still being refined. The location at Nunn was lost to development and the experiment was moved to Briggsdale. Sentinel plant data collected at Nunn and Briggsdale by University of Wyoming cooperators indicated that rates of parasitism of Russian wheat aphid were greater in wheat grown in intensified rotations than in conventional wheat fallow. This is our first experimental evidence supporting the hypothesis that biological control will be more effective in more diverse cropping systems. No experimental insecticide treatment was superior to commercial standards used in winter wheat. Lambda-cyhalothrin was confirmed as a promising substitute for chlorpyrifos in malting barley. Barley producers have been without a safe and effective insecticide for Russian wheat aphid management. |
| 2000 | Russian wheat aphid remains the most significant pest of small grains in Colorado. Economic impact varies from year to year, with 1999 - 2000 having significant aphid activity, although insect effects were confounded with the drought conditions that persisted through most of the growing season. Current research emphasizes plant resistance and Russian wheat aphid management within the larger context of dryland cropping systems. A twelfth year of monitoring flights with suction traps was completed. Suction traps have been relocated to the three dryland agroecosystem study sites to provide a long-term record of Russian wheat aphid activity. Pest and beneficial insect monitoring was continued at three cropping system study locations (Akron, Briggsdale, Lamar). Arthropod sampling and monitoring methodology have been standardized and a weed sampling component was added. Crop performance was poor and insect activity was relatively low at all three locations due to dry conditions. No experimental insecticide treatment was superior to commercial standards used in winter wheat. Lambda-cyhalothrin was confirmed as a promising substitute for chlorpyrifos in malting barley. Treated plots yielded about three times as much as untreated plots, underscoring the importance of this pest to barley production in the region. Barley producers have been without a safe and effective insecticide for Russian wheat aphid management. |
| 2001 | Russian wheat aphid remains the most significant pest of small grains in Colorado. Economic impact varies from year to year, with 2000 - 2001 having the least aphid activity on record. The ability to infest field plots with greenhouse-reared aphids allowed us to collect usable data in spite of the paucity of naturally occurring infestations. Current research emphasizes plant resistance and Russian wheat aphid management within the larger context of dryland cropping systems. A thirteenth year of monitoring flights with suction traps was completed. Suction traps are operated at each of the three dryland agroecosystem study sites to provide a long-term record of Russian wheat aphid activity. Pest and beneficial insect monitoring was continued at three cropping system study locations (Akron, Briggsdale, and Lamar). For a second year, crop performance was poor and insect activity was relatively low at all three locations due to dry conditions. 115 Russian wheat aphid resistant barley lines were compared for agronomic performance to `Otis' under dryland conditions. Five lines performed well and will be retested next season. This study was conducted in cooperation with the Agricultural Research Service. Thiamethoxam (Adage seed treatment) treated aphid-susceptible malt barley had fewer Russian wheat aphids than lambda-cyhalothrin treated susceptible barley or untreated aphid-resistant barley. Adage treatments also yielded more than the other treatments under severe infestation conditions. Yield was reduced 78% in the untreated control, indicating the major damage potential that this pest poses to barley production in the region. Adage seems to have potential as a preventive treatment for use by growers at high risk for aphid infestation . |
| 2002 | Russian wheat aphid remains the most significant pest of small grains in Colorado. Economic impact varies from year to year, with 2001 - 2002 having moderate aphid activity but very little treatment because of the drought conditions. Current research emphasizes plant resistance and Russian wheat aphid management within the larger context of dryland cropping systems. Two new Russian wheat aphid resistant winter wheat varieties, Ankor and Stanton, were compared to the susceptible Akron and the resistant Halt at three locations. The resistant varieties were similar in aphid infestation incidence and intensity. No yield components were affected by the aphid, with the exception of 1000 seed weight in Halt. A fourteenth year of monitoring flights with suction traps was completed. Suction traps are operated at each of the three dryland agroecosystem study sites to provide a long-term record of Russian wheat aphid activity. Pest and beneficial insect monitoring was continued at three cropping system study locations (Akron, Briggsdale, Lamar). For a third year, crop performance was poor and insect activity was relatively low at all three locations due to dry conditions. Carabid beetles, important generalist predators, were monitored in two and three year rotations at each location. More than 60 species have been identified, with most species found at a single location. Twenty Russian wheat aphid resistant barley lines were compared for agronomic performance to 'Otis' under dryland conditions. A few lines were able to produce some yield in spite of the severe drought conditions. Four lines representing two resistance sources will be tested for a third season. This study was conducted in cooperation with the Agricultural Research Service. Thiamethoxam (Cruiser seed treatment) again provided better aphid control than the most effective commercial foliar insecticide treatments. Thiamethoxam also provided better Russian wheat aphid control than several experimental aphid-resistant malt barley lines . Plots treated with thiamethoxam yielded more than the other treatments under severe infestation conditions. Yield was reduced 88% in the untreated control, indicating the major damage potential that this pest poses to barley production in the region. Thiamethoxam has potential as a preventive treatment for use by growers at high risk for aphid infestation. |
| 2003 | Russian wheat aphid remains the most significant pest of small grains in Colorado. Economic impact varies from year to year, with 2002 - 2003 having moderate to high aphid activity but very little treatment because of dry conditions. Current research emphasizes plant resistance and Russian wheat aphid management within the larger context of dryland cropping systems. Mixtures of a Russian wheat aphid resistant winter wheat variety (Prairie Red) and a susceptible variety (TAM 107) were evaluated at three infestation levels at three locations. Aphid infestation incidence and intensity was reduced when at least 50% of the plants were resistant. Yield reductions were observed when 50% or more of the plants were susceptible. A fifteenth year of monitoring flights with suction traps was completed. Suction traps are operated at each of the three dryland agroecosystem study sites to provide a long-term record of Russian wheat aphid activity. Pest and beneficial insect monitoring was continued at three cropping system study locations (Akron, Briggsdale, Lamar). For a fourth year, crop performance was poor and insect activity was relatively low at all three locations due to dry conditions. Carabid beetles and spiders, important generalist predators, were monitored in two and three year rotations at each location. More than 50 species of carabid beetles and 20 species of spiders have been identified, with most species found at just one location. Five to ten Russian wheat aphid resistant barley lines were compared for agronomic performance to Otis under dryland conditions at five locations. Four lines representing one resistance sources and one line from a second source will be tested for a fourth season. This study was conducted in cooperation with the Agricultural Research Service. Unusual Russian wheat aphid damage was observed on resistant varieties in southeast Colorado. Aphids were collected from damaged plants and compared to colony aphids on resistant and susceptible varieties in the greenhouse. Plant damage scores (1-9 scale) for colony aphids, averaged over all resistant and all susceptible varieties, were 2.6 and 7.3, respectively. Plant damage scores for field collected aphids, averaged over all resistant and all susceptible varieties, were 8.4 and 9.0, respectively. These results confirmed the presence of a new Russian wheat aphid biotype in Colorado. Subsequent screening of resistant breeding materials indicated that the new aphid is virulent to all resistance sources except those containing Dn7. Additional sources of resistance have been identified since that initial screening. |
| 2004 | Russian wheat aphid remains the most significant pest of small grains in Colorado. Economic impact varies from year to year, with 2003 - 2004 having widespread but moderate aphid activity but very little treatment because of poor crop condition. Current research emphasizes plant resistance and Russian wheat aphid management within the larger context of dryland cropping systems. A sixteenth year of monitoring flights with suction traps was completed. Suction traps are operated at each of the three dryland agroecosystem study sites to provide a long-term record of Russian wheat aphid activity. Pest and beneficial insect monitoring was continued at three cropping system study locations (Akron, Briggsdale, Lamar). Crop performance was mixed as growing conditions for summer crops improved and insect activity increased similarly. Carabid beetles and spiders, important generalist predators, were monitored in two and three year rotations at each locations. More than 50 species of carabid beetles have been identified, with location and year having greater influence than cropping system on species composition and activity. More than 20 species of spiders in seven families have been identified, with gnaphosids and linyphiids being the most generally dominant groups. Nine Russian wheat aphid resistant barley lines were compared for agronomic performance to imidacloprid-protected cultivar Otis under dryland conditions at five Colorado locations. Two lines containing distinct sources of resistance have been selected for joint release by the Agricultural Research Service in cooperation with Colorado, Idaho and Nebraska. Unusual Russian wheat aphid damage was observed on resistant winter wheat varieties in southeast Colorado in 2003, leading to the identification of Russian wheat aphid Biotype 2. All sources of resistance in the Colorado wheat breeding program were screened, along with 765 Iranian lines and more than 3,000 lines from the national wheat germplasm collection, for resistance to Biotype 2. Lines identified as resistant to Biotype 2 will be rescreened with the original aphid (Biotype 1) to identify sources of resistance to be used in the breeding program. A field survey for Russian wheat aphid Biotypes 1 and 2 was conducted, with 43 of the 91 usable samples being identified as Biotype 1 and the remainder as Biotype 2. The survey revealed the presence of an additional biotype in Montezuma County and concurrent research by USDA-ARS scientists has identified an additional three biotypes from northern Wyoming and the Texas Panhandle. Germplasm identified as resistant to Biotypes 1 and 2 will be screened with these additional biotypes. Methods for biotype characterization have been formalized, and Biotypes 1 , 2 and "Montezuma" have been characterized with these methods. |
| 2005 | Russian wheat aphid remains the most significant pest of small grains in Colorado. Economic impact varies from year to year, with 2004 - 2005 having widespread aphid activity, particularly in the southeast part of the state where treatment was widespread. Current research emphasizes plant resistance and Russian wheat aphid management within the larger context of dryland cropping systems. A seventeenth year of monitoring flights with suction traps was completed. Suction traps are operated at each of the three dryland agroecosystem study sites to provide a long-term record of Russian wheat aphid activity. Trap catches were substantially higher than in the past several years. Pest and beneficial insect monitoring was continued at three cropping system study locations (Akron, Briggsdale, Lamar). Crop performance was mixed as growing conditions for summer crops improved and insect activity increased similarly. Spiders, important generalist predators, were monitored in two and three year rotations at each locations. More than 20 species of spiders in seven families have been identified, with gnaphosids and linyphiids being the most generally dominant groups. Unusual Russian wheat aphid damage was observed on resistant winter wheat varieties in southeast Colorado in 2003, leading to the identification of Russian wheat aphid Biotype 2. A field survey for Russian wheat aphid Biotypes 1 and 2 was conducted, with 82% of the 122 usable samples being identified as Biotype 2, compared to 52% in 2004. One additional biotype was identified from a noncrop host at Pritchett. High elevation noncrop hosts were surveyed in an initial attempt to identify sources of biotypic diversity, with apterae found at 10,000 feet. An additional 5,000 lines from the national wheat germplasm collection were screened for resistance to Biotype 2. Approximately 300 lines identified as resistant to Biotype 2 were rescreened with Biotype 1, with about 50 lines showing resistance to both biotypes. |
| 2006 | Russian wheat aphid remains the most significant pest of small grains in Colorado. Economic impact varies from year to year, with 2005 - 2006 having widespread aphid activity, but not at the levels observed in the previous season. Current research emphasizes plant resistance and Russian wheat aphid management within the larger context of dryland cropping systems. An eighteenth year of monitoring flights with suction traps was completed. Suction traps are operated at the Plainsman Research Center and at each of the three dryland agroecosystem study sites to provide a long-term record of Russian wheat aphid activity. Trap catches were uniformly lower than the previous year, verifying field observations. Pest and beneficial insect monitoring was continued at three cropping system study locations (Akron, Briggsdale, Lamar). This was a transition year for crop performance observations because production systems have been modified to increase the use of forage crops and eliminate sunflower. In addition to forage crops, Stoneham, a Russian wheat aphid resistant dryland spring feed barley, has been added to several cropping systems at Akron and Briggsdale. Spiders, important generalist predators, were monitored again in two and three year rotations at each locations. More than 20 species of spiders in seven families have been identified, with gnaphosids and linyphiids being the most generally dominant groups. Unusual Russian wheat aphid damage was observed on resistant winter wheat varieties in southeast Colorado in 2003, leading to the identification of Russian wheat aphid Biotype 2. A field survey for Russian wheat aphid Biotypes 1 and 2 was conducted, with 93% of the 118 usable samples being identified as Biotype 2, compared to 52 and 82% in 2004 and 2005, respectively. Eight biotypes, five from Colorado, have been characterized, although only Biotype 2 is considered to be a significant threat to the Colorado wheat industry. High elevation noncrop hosts were surveyed for a second season. Host species are similar to those observed in wheat production areas in earlier studies, but they seem to be more suitable oversummering hosts at higher elevations because of delayed maturity. An additional 6,000 lines from the national wheat germplasm collection and other sources were screened for resistance to Biotype 2. Approximately 300 lines identified as resistant to Biotype 2 were rescreened with Biotype 1, with about 50 lines showing resistance to both biotypes. Studies to broaden the basis of resistance, primarily through leaf pubescence, to Russian wheat aphid have been initiated. |
| Impact | |
| 1999 | Russian wheat aphid resistant varieties allow producers to grow wheat without insecticides. Other management approaches are necessary to avoid aphids that overcome this resistance. We are trying to enhance biological control through increased crop diversity and provide wheat growers with another economically and environmentally sound control for this important pest. |
| 2000 | Russian wheat aphid resistant varieties allow producers to grow wheat without insecticides. Other management approaches are necessary to avoid aphids that overcome this resistance. We are trying to enhance biological control through increased crop diversity and provide wheat growers with another economically and environmentally sound control for this important pest. Barley producers also need management options for this pest. |
| 2001 | Russian wheat aphid resistant varieties allow producers to grow wheat without insecticides. Other management approaches are necessary to avoid aphids that overcome this resistance. We are trying to enhance biological control through increased crop diversity and provide wheat growers with another economically and environmentally sound control for this important pest. Barley producers also need management options for this pest. A resistant variety holds promise for dryland producers. Varietal resistance and a new seed treatment seem to be viable options for irrigated producers. |
| 2002 | Russian wheat aphid resistant varieties allow producers to grow wheat without insecticides. Other management approaches are necessary to avoid aphids that overcome this resistance. We are trying to enhance biological control through increased crop diversity and provide wheat growers with another economically and environmentally sound control for this important pest. Barley producers also need management options for this pest. A resistant variety holds promise for dryland producers. Varietal resistance and thiamethoxam seed treatment are viable options for irrigated barley producers, and seem compatible with the management approaches recommended for the newly introduced cereal leaf beetle. |
| 2003 | Russian wheat aphid resistant varieties have allowed producers to grow wheat without insecticides. This past season roughly 25% of Colorado wheat acres were planted to resistant varieties, with this figure approaching 50% in areas with more consistent aphid infestations. The occurrence of a new biotype greatly diminishes the value of currently deployed resistant varieties, and it is unclear how long it will take to provide producers with new varieties resistant to both biotypes. Other management approaches will be necessary to manage the new biotype. Effective chemical controls and use guidelines are available. We are trying to enhance biological control through increased crop diversity and thus provide wheat growers with another economically and environmentally sound control for this important pest. Barley producers also need management options for this pest. A resistant variety holds promise for dryland producers. Thiamethoxam seed treatment seems to be a viable option for irrigated barley producers that is compatible with the management approaches recommended for the newly introduced cereal leaf beetle. |
| 2004 | Russian wheat aphid resistant varieties have allowed producers to grow wheat without insecticides. Roughly 25% of Colorado wheat acres are planted to resistant varieties, with this figure approaching 50% in areas with more consistent aphid infestations. The occurrence of a new biotype diminishes the value of currently deployed resistant varieties, although the survey results indicate that resistant varieties still have significant value. It is unclear how long it will take to provide producers with new varieties resistant to Biotypes 1 and 2, and the identification of an additional four biotypes raises questions as to whether resistance to just two biotypes will be sufficient. Other management approaches will be necessary to manage the new biotypes until effective resistant varieties are available. Effective chemical controls and use guidelines are available. We are trying to enhance biological control through increased crop diversity and thus provide wheat growers with another economically and environmentally sound control for this important pest. Barley producers also need management options for this pest. Release of two varieties, resistant to the known biotypes, planned for 2005 holds promise for dryland producers. Thiamethoxam seed treatment seems to be a viable option for irrigated barley producers that is compatible with the management approaches recommended for the newly introduced pest, cereal leaf beetle. |
| 2005 | Russian wheat aphid resistant varieties have allowed producers to grow wheat without insecticides. Acreage of resistant varieties has remained constant in spite of the widespread occurrence of Biotype 2 - survey results indicate that Biotype 2 predominates throughout the wheat producing counties. This indicates that these varieties are valuable to wheat producers for more than just aphid resistance. The identification of an additional five biotypes argues for efforts to develop a broader basis for aphid resistance in Colorado winter wheat cultivars . Release of two barley varieties, resistant to the known biotypes, planned for 2006 holds promise for diversified dryland producers. |
| 2006 | Russian wheat aphid resistant varieties have allowed producers to grow wheat without insecticides. Acreage of resistant varieties has remained constant in spite of the widespread occurrence of Biotype 2 - survey results indicate that predominance of Biotype 2 continues to increase in wheat producing counties. This indicates that these varieties are valuable to wheat producers for more than just aphid resistance. The identification of an additional six biotypes argues for efforts to develop a broader basis for aphid resistance in Colorado winter wheat cultivars. Release of two barley varieties, resistant to the known biotypes, in 2006 provides another diversification option for dryland producers. |
| Publications | |
| 1993 |
ARMSTRONG, J.S., F.B. PEAIRS, S.D. PILCHER, & C.C. RUSSELL. 1993. The effect of planting time insecticides & liquid fert ilitzer on the RWA & the lesion nematode (Pratylenchus thorn ei) on winter wheat. J. Kans. Ento. Soc. 66:69-7 BROOKS, L., S. AMOSSON, G. HEIN, G. JOHNSON, D. MCBRIDE, W. MASSEY, W. MORRISON, F. PEAIRS, & J. SCHULTZ. 1993. Economic impact of the RWA in the western United States: 1990-1991. Great Plains Agric. Council Public. 143, 16 pp. LEGG, D., S. AMOSSON, L. BROOKS, G. HEIN, G. JOHNSON, D. MCB RIDE, W. MASSEY, W. MORRISON, F. PEAIRS, AND M. WEISS. 1993. Economic impact of the RWA in the western United States: 19 91-1992. Great Plains Agric. Public. 147, 17 pp. WRAIGHT, S.P., T.J. POPRAWSK, W.L. MEYER, & F.B. PEAIRS. 199 3. Natural enemies of RWA (Homoptera: Aphididae) & associate d cereal aphid species in spring-planted wheat and barley in Colorado. Environ. Entomol. 22:1383-1391. |
| 1994 |
ARMSTRONG, J. 1994. The overwintering biology of the Russian wheat aphid diuraphis noxia (mordvilko) on the northeastern plains of Colorado. PhDDissertation, Colorado State University DONG, H. ET AL. 1994. Leaf unrolling of three wheat genotypes in Russian wheat aphid extracts. Cereal Research Commun. 22:375-9 HAMMON, R. 1994. Factors influencing the overwintering of Russian wheat aphid in western Colorado. pp 68 - 72 IN Peairs, Kroening, Simmons (comp). Proc. 6thRussian Wheat Aphid workshop. Fort Collins, CO KROENING, M. 1994. Economic impact of Russian wheat aphid on susceptible and resistant varieties in Colorado. pp 143-8 IN Peairs, Kroening, Simmons(comp). Proc. 6th Russian Wheat Aphid workshop, Fort Collins, CO LEGG, D.E. ET AL. 1994. Binomial sequential sampling plans and decision support algorithms for managing the Russian wheat aphid (homoptera: aphididae) in small grains. J. Econ. Entomol. 87:1513-33 QUICK, J. 1994. Development of cultivars resistant to Russian wheat aphid. pp 37-41. Peairs, Kroening, Simmons (COMP). Proc. 6th Russian Wheat Aphid workshop. Fort Collins, CO RANDOLPH, T. ET AL. 1994. Tritrophic relationships: A comparison of TAM 107 and CORWA1 winter wheat varieties with Russian wheat aphid and hippodamia variegata. pp 238-41. Proc. 6th Russian Wheat Aphid workshop, Fort Collins,CO WALKER, C. & F. PEAIRS. 1994. Cultural control of Russian wheat aphid. pp 42-51 IN Peairs, Kroening, Simmons (Comp). Proc. 6th Russian Wheat Aphid workshop. Fort Collins, CO |
| 1995 |
DONG, H., J. QUICK, D. BRIGHAM, L. BJOSTAD, J. RUDOLPH & F. PEAIRS. 1994. Leaf unrolling of 3 wheat genotypes in Russian wheat aphid extracts. Cereal Res. Commun. 22: 375-9 ELLIOTT, N., J. BURD, J. ARMSTRONG, C. WALKER, D. REED & F. PEAIRS. 1995. Release and recovery of imported parasitoids of the Russian wheat aphid in eastern Colorado. Southwest Entomol. 20: 125-9 QUICK, J., G. ELLIS, R. NORMAN, J. STROMBERGER, J. SHANAHAN, F. PEAIRS, J. RUDOLPH, & K. LORENZ. 1996. Registration of 'Halt' wheat. Crop Sci. 36: 210 QUICK, J., K. NKONGOLO, F. PEAIRS & J. RUDOLPH. 1996. Registration of Russian wheat aphid-resistant wheat germplam CORWA1. Crop Sci. 36: 217 |
| 1997 |
Hammon, R. W., J. S. Armstrong, W. L. Meyer, C. Walker, & F. B. Peairs. 1997. Alternate hosts of the Russian wheat aphid in Colorado. Colorado State Univ. Agric. Exp. Sta. Tech. Rep. TR97-2, 19 pp Hawley, C. 1997. Categories of resistance at different growth stages in `Halt', a winter wheat resistant to Russian wheat aphid (Homoptera: Aphididae). MS Thesis, Colorado State University |
| 1998 |
Archer, T. L., F. B. Peairs, K. S. Pike, G. D. Johnson & M. K. Kroening. 1998. Economic injury level for the Russian wheat aphid (Homoptera: Aphididae) on winter wheat in several climate zones. J. Econ. Entomol. 91: 741 - 7 Archer, T. L., G. D. Johnson, F. B. Peairs, K. S. Pike & M. K. Kroening. 1998. Effect of plant phenology and climate on Russian wheat aphid (Homoptera: Aphididae) damage to winter wheat. Environ. Entomol. 27: 221 - 31 Peairs, F. B. 1998. Russian wheat aphid management. Pp. 51 - 4 in, R. Karow & B. Reed, compilers. Proceedings Inaugural National Wheat Industry Research Forum, San Diego, CA. January 14 - 15, 1998 |
| 1999 |
Bregitzer, P., D. W. Mornhinweg, B. L. Jones, A. D. Budde, F. B. Peairs, T. L. Randolph, D. R. Porter, & J. A. Webster. 1999. Malting quality of RWA-infested, RWS-resistant barley. P. 31 - 33. Proceedings, 16th American Barley Researchers Workshop, Idaho Fall, Idaho. July 11 - 15, 1999 D. W. Mornhinweg, P. Bregitzer, B. L. Jones, F. B. Peairs, T. L. Randolph, D. R. Porter, & J. A. Webster. 1999. Effect of early and late RWA infestations on agronomics and malting quality of adapted barley germplasm lines. P. 69. Proceedings, 16th American Barley Researchers Workshop, Idaho Fall, Idaho. July 11 - 15, 1999 G. A. Peterson, D. G. Westfall, F. B. Peairs, L. Sherrod, D. Poss, W. Gangloff, K. Larson, D. L. Thompson, L. R. Ahuja, M. D. Koch, & C. B. Walker. 1999. Sustainable dryland agroecosystem management. Colorado State Univ. Agric. Exp. Sta. Tech. Bull. TB99-1, 86 pp Hammon, R. W., D. V. Sanford, M. W. Stack, A. Berrada & F. B. Peairs. 1999. Dryland winter wheat planting date and Russian wheat aphid studies in southwestern Colorado, 1990 - 1998. Colorado State Univ. Agric. Exp. Sta. Tech. Rep. TR99-2, 13 pp Hammon, R. W., T. L. Randolph, J. S. Armstrong, C. B. Walker, J. B. Rudolph, M. D. Koch, W. L. Meyer, & F. B. Peairs. 1999. Suction trapping of selected small grain aphids in Colorado, 1988 - 1998. Colorado State Univ. Agric. Exp. Sta. Tech. Bull. LTB99-1, 28 pp McBride, T., M. Eisenach, J. Adams, K. Nye, P. Ayers & F. Peairs. 1999. Can spring grazing pay in northern Colorado? Pp. 12 - 13 in, J. Johnson, ed. Making better decisions: 1998 Colorado wheat variety performance trials. Colorado State Univ. Agric. Exp. Sta. Tech. Rep. TR99-7, 19 pp Peairs, F. B., T. Randolph, C. Walker, M. Koch, , J. Rudolph, J. Quick, & J. Johnson. 1999. Managing Russian wheat aphid with resistant wheats. P. 56 in, R. Karow & B. Reed, compilers. Proceedings, The 2nd Annual National Wheat Industry Research Forum, Nashville, TN. February 3 - 5, 1999 Pilcher, S., F. Peairs, G. Wilde, G. Hein, & R. Higgins. 1999. Insect pest identification and control. Pp. 13 -16 in, R. Meyer, D. Belshe, D. O'Brian & R. Darling, eds. High Plains Sunflower Production Handbook. Kansas State University Cooperative Extension Bull. MF2384, Manhattan, KS |
| 2000 |
G. A. Peterson, D. G. Westfall, F. B. Peairs, L. Sherrod, D. Poss, W. Gangloff, K. Larson, D. L. Thompson, L. R. Ahuja, M. D. Koch, & C. B. Walker. 2000. Sustainable dryland agroecosystem management. Colorado State Univ. Agric. Exp. Sta. Tech. Bull. TB00-3, 83 pp. Meyer, R. F. & F. B. Peairs. 2000. Harvest and storage considerations. Pp. 30 - 2 in, Peairs, F. B., ed. Colorado Wheat Production Handbook. Colorado Association of Wheat Growers, Lakewood , CO. 55 pp. Meyer, R. F. & F. B. Peairs. 2000. Wheat planting considerations. Pp. 17 - 9 in, Peairs, F. B. , ed. Colorado Wheat Production Handbook. Colorado Association of Wheat Growers, Lakewood, CO. 55 pp. Peairs, F. B. & G. L. Hein. 2000. Key insect and mite pests of wheat. Pp. 20 - 3 in, Peairs, F . B., ed. Colorado Wheat Production Handbook. Colorado Association of Wheat Growers, Lakewood, CO. 55 pp. Peairs, F. B. 2000. Preventing insects in farm-stored grain. Pp. 16 in, J. Johnson, ed. Making better decisions: 1999 Colorado wheat variety performance trials. Colorado State Univ. Agric. Exp. Sta. Tech. Rep. TR00-3, 23 pp. Peairs, F. B., ed. 2000. Colorado Wheat Production Handbook. Colorado Association of Wheat Growers, Lakewood, CO. 55 pp. Peairs, F. B., R. F. Meyer & D. B. Bosley. 2000. Managing spring freeze injury. Pp. 28 - 9 in, Peairs, F. B., ed. Colorado Wheat Production Handbook. Colorado Association of Wheat Growers, Lakewood, CO. 55 pp. Walker, C. B. & F. B. Peairs. 2000. Grazing winter wheat. Pp. 37 - 8 in, Peairs, F. B., ed. Colorado Wheat Production Handbook. Colorado Association of Wheat Growers, Lakewood, CO. 55 pp . Walters, S. M. F. B. Peairs & S. D. Pilcher. 2000. 1999 Colorado field crop insect management research and demonstration trials. Colorado State Univ. Agric. Exp. Sta. Tech. Bull. LTB00-1, 55 pp. |
| 2001 |
Quick, J. S., J. A. Stromberger, S. Clayshulte, B. Clifford, J. J. Johnson, F. B. Peairs, J. B . Rudolph, and K. Lorenz. 2001. Registration of `Prowers' Wheat. Crop Science 41: 928 - 9. Quick, J. S., S. D. Haley, J. A. Stromberger, S. Clayshulte, B. Clifford, J.J. Johnsona, F.B. Peairs, J. B. Rudolph, and K. Lorenz. 2001. Registration of `Prowers 99' Wheat. Crop Science 41: 929. Quick, J.S., J.A. Stromberger, S. Clayshulte, B. Clifford, J.J. Johnson, F.B. Peairs, J.B. Rudolph, and K. Lorenz. 2001. Registration of `Yumar' Wheat. Crop Sci 41: 1363-1364. Quick, J.S., J.A. Stromberger, S. Clayshulte, B. Clifford, J.J. Johnson, F.B. Peairs, J.B. Rudolph, and K. Lorenz. 2001. Registration of `Prairie Red' Wheat. Crop Sci 41: 1362-1363. Walters, S. M., F. B. Peairs & A. Gebre-Amlak. 2001. 2001 Colorado field crop insect management research and demonstration trials. Colorado State Univ. Agric. Exp. Sta. Tech. Bull . LTB01-2, 38 pp. Walters, S. M., F. B. Peairs & A. Gebre-Amlak. 2001. 2000 Colorado field crop insect management research and demonstration trials. Colorado State Univ. Agric. Exp. Sta. Tech. Bull . LTB01-1, 46 pp. |
| 2002 |
Haley, S. D. T. J. Martin, J. S. Quick, D. L. Seifers, J. A. Stromberger, S. R. Clayshulte, B. L. Clifford, F. B. Peairs, J. B. Rudolph, J. J. Johnson, B. S. Gill, and B. Friebe. 2002. Registration of CO960293-2 wheat germplasm resistant to wheat streak mosaic virus and Russian wheat aphid. Crop Sci. 42: 1381 - 1382. Peairs, F. B. and S. D. Haley. 2002. Russian wheat aphid. Pp. 260 - 270 in: Berzonsky, W. A., H. Ding, S. D. Haley, M. O. Harris, R. J. Lamb, R. I. H. McKenzie, H. W. Ohm, F. L. Patterson, F. B. Peairs, D. R. Porter, R. H. Ratcliffe, and T. G. Shanower. Breeding wheat for resistance to insects. Plant Breeding Reviews 22: 221 - 96. Randolph, T. L., M. K. Kroening, J. B. Rudolph, F. B. Peairs, and R. F. Jepson. 2002. Augmentative releases of commercial biological control agents for Russian wheat aphid management in winter wheat. Southwestern Entomologist 27: 37 - 44. |
| 2003 |
Haley, S. D., J. S. Quick, T. J. Martin, J. J. Johnson, F. B. Peairs, J. A. Stromberger, S. R. Clayshulte, B. L. Clifford, and J. B. Rudolph. 2003. Registration of 'Avalanche' wheat. Crop Sci. 43:432. Haley, S. D., M. D. Lazar, J. S. Quick, J. J. Johnson, G. L. Peterson, J. A. Stromberger, S. R . Clayshulte, B. L. Clifford, T. A. Pester, S. J. Nissen, P. H. Westra, F. B. Peairs, and J. B . Rudolph. 2003. Above winter wheat. Can. J. Plant Sci. 83:107-108. Haley, S., J. Johnson, and F. Peairs. 2003. Hard white wheat breeding at CSU. Pp. 49 - 52 in, Haley, S., ed. Colorado Wheat Production Handbook: Clearfield Wheat and Hard White Wheat. Colorado Association of Wheat Growers, Lakewood, CO. 56 pp. Haley, S., J. Johnson, F. Peairs, and P. Westra. 2003. Clearfield wheat breeding at CSU. Pp. 17 - 20 in, Haley, S., ed. Colorado Wheat Production Handbook: Clearfield Wheat and Hard White Wheat. Colorado Association of Wheat Growers, Lakewood, CO. 56 pp. Hawley, C. J., F. B. Peairs, and T. L. Randolph. 2003. Categories of resistance at different growth stages in Halt, a winter wheat resistant to the Russian wheat aphid (Homoptera: Aphididae). J. Econ. Entomol. 96: 214 - 219. Lazar, M. D., S. D. Haley, J. S. Quick, J. J. Johnson, G. L. Peterson, J. A. Stromberger, S. R . Clayshulte, B. L. Clifford, T. A. Pester, S. J. Nissen, P. H. Westra, F. B. Peairs, and J. B . Rudolph. 2003. AP502 CL winter wheat. Can. J. Plant Sci. 83:109-110. Miller, H. R., T. L. Randolph, and F. B. Peairs. 2003. Categories of resistance at four growth stages in three wheats resistant to the Russian wheat aphid (Homoptera: Aphididae). J. Econ. Entomol. 96: 673 - 9. Randolph, T. L., F. B. Peairs, M. K. Kroening, J. S. Armstrong, R. W. Hammon, C. B. Walker, and J. S. Quick. 2003. Plant damage and yield response to the Russian wheat aphid (Homoptera: Aphididae) on susceptible and resistant winter wheats in Colorado. J. Econ. Entomol. 96: 352 - 61. Walters, S. M., F. B. Peairs & A. Gebre-Amlak. 2003. 2002 Colorado field crop insect management research and demonstration trials. Colorado State Univ. Agric. Exp. Sta. Tech. Bull . LTB03-2, 45 pp. |
| 2004 |
Haley, S. D., Peairs,F.B., Walker,C.B., Rudolph,J.B., and Randolph,T. L. 2004. Occurrence of a new Russian wheat aphid biotype in Colorado. Crop Sci. 44:1589-1592. Haley, S. D., Quick,J.S., Johnson,J.J., Peairs,F.B., Stromberger,J.A., Clayshulte,S.R., Clifford,B.L., Rudolph,J.B., Chung,O.K., and Seabourn,B. W. 2004. Registration of 'Ankor' wheat. Crop Sci. 44: 1025 - 1026. Peairs, F.B. 2004. Wheat pests and their management. Pp. 2529 - 2545 in J. L. Capinera, ed. Encyclopedia of Entomology. Kluwer Academic Publishers, Boston. Peairs, F.B., Haley,S.D., and Johnson,J.J. 2004. Managing the new Russian wheat aphid biotype. Pp. 22 - 24 in Johnson, J. J., ed. 2004. Making better decisions: 2003 Colorado wheat variety performance trials. Colorado State Univ. Agric. Exp. Sta. Tech. Rep. TR04-03, 32 pp. Peterson, G. A., Westfall,D.G., Peairs,F.B., Sherrod,L., Poss,D., Gangloff,W., Larson,K., Thompson,D.L., Ahuja,L.R., Koch,M.D. and Walker,C.B. 2004. Sustainable dryland agroecosystem management. Colorado State Univ. Agric. Exp. Sta. Tech. Bull. TB04-05, 124 pp. |
| 2005 |
Collins, M.B., Haley, S.D., Peairs, F.B., and Rudolph, J.B. 2005. Biotype 2 Russian wheat aphid resistance among wheat germplasm accessions. Crop Sci. 45:1877-1880 Collins, M.B., Haley, S.D., Randolph, T.L., Peairs, F.B., and Rudolph, J.B. 2005. Comparison of Dn4- and Dn7-carrying spring wheat genotypes artificially infested with Russian wheat aphid (Homoptera: Aphididae) Biotype 1. J. Econ. Entomol. 98:1698-1703. Haley, S.D., Quick, J.S., Johnson, J.J., Peairs, F.B., Stromberger, J.A., Clayshulte, S.R., Clifford, B.L., Rudolph, J.B., Seabourn, B.W., Chung, O.K., Jin, Y., and Kolmer, J. 2005. Registration of 'Hatcher' wheat. Crop Sci. 45:2654-2656. Peairs, F. 2005. Insect and mite pests of wheat. Pp. 63-78 in 2005 Colorado Wheat Handbook. Colorado Association of Wheat Growers, Centennial, CO. Peairs, F., Randolph, T., Haley, S., Johnson, J., Rudolph, J.,Walker, T., Koch, M. and Hammon, R. 2005. Managing new Russian wheat aphid biotypes. Pp. 23 - 26 in Johnson, J. J., ed. 2005. Making better decisions: 2004 Colorado wheat variety performance trials. Colorado State Univ. Agric. Exp. Sta. Tech. Rep. TR05-09, 28 pp. Randolph, T.L., Peairs, F.B., Koch, M., Walker, C.B., and Quick, J.S. 2005. Influence of three resistance sources in winter wheat derived from TAM 107 on yield response to Russian wheat aphid. J. Econ. Entomol. 98:389-394. Randolph, T.L., Peairs, F.B., Koch, M., Walker, C.B., Stubbs, J.R., Quick, J.S., and Haley, S .D. 2005. Yield response and categories of resistance to Russian wheat aphid in four Dn4 hard red winter wheat cultivars. J. Econ. Entomol. 98:588-594. |
| 2006 |
Burd, J. D., D. R. Porter, G. J. Puterka, S. D. Haley, and F. B. Peairs. 2006. Biotypic variation among North American Russian wheat aphid (Homoptera: Aphididae) populations. J. Econ . Entomol. 99: 1862-1866. Chander, S., L. R. Ahuja, F. B. Peairs, P.K. Aggarwal, and N. Kalra. 2006. Modeling the effect of Russian wheat aphid, Diuraphis noxia (Mordvilko) and weeds in winter wheat as guide to management. Agricultural Systems 88: 494 - 513. G. J. Puterka, Burd, J. D., D. W. Mornhinweg, S. D. Haley, and F. B. Peairs. 2006. Response of resistant and susceptible barley to infestations of five Diuraphis noxia (Homoptera: Aphididae) biotypes. J. Econ. Entomol. 99: 2151 - 2155. Haley, S. D., J. J. Johnson, F. B. Peairs, J. S. Quick, P. H. Westra, J. A. Stromberger, S. R. Clayshulte, B. L. Clifford, J. B. Rudolph, B. W. Seabourn, O. K. Chung, Y. Jin, and J. Kolmer. 2006. Registration of 'Protection' wheat. Crop Sci. 46: 995 - 996. Haley, S. D., J. J. Johnson, F. B. Peairs, J. S. Quick, P. H. Westra, J. A. Stromberger, S. R. Clayshulte, B. L. Clifford, J. B. Rudolph, A. Giura, B. W. Seabourn, O. K. Chung, Y. Jin, and J. Kolmer. 2006. Registration of 'Bond CL' wheat. Crop Sci. 46: 993 - 995. Meyer, R. F. and F. B. Peairs. 2006. Harvest and storage considerations. Pp. 63 - 66 in, Peairs, F. B., ed. Colorado Wheat Production Handbook, 2nd ed. Colorado Association of Wheat Growers, Lakewood, CO. 96 pp. Peairs, F. B. Russian wheat aphid management. 2006. Pp. 28 - 32 in, Peairs, F. B., ed. Colorado Wheat Production Handbook, 2nd ed. Colorado Association of Wheat Growers, Lakewood, CO. 96 pp. Peairs, F. B., ed. 2006. Colorado Wheat Production Handbook, 2nd ed. Colorado Association of Wheat Growers, Lakewood, CO. 96 pp. Peairs, F., T. Randolph, S. Haley, J. Johnson, J. Rudolph, J. Stromberger, T. Walker, M. Koch, and R. Hammon. 2006. Managing new Russian wheat aphid biotypes. Pp. 28 - 29 in Johnson, J. J., ed. 2006. Making better decisions: 2005 Colorado wheat variety performance trials. Colorado State Univ. Agric. Exp. Sta. Tech. Rep. TR06-09, 40 pp. Randolph, T. L., F. B. Peairs, M. Koch, and C. B. Walker. 2006. Yield response to Russian wheat aphid (Hemiptera: Aphididae) in three resistant wheats in eastern Colorado. Southwestern Entomologist 31: 25 - 32. Walker, C. B. and F. B. Peairs. 2006. Grazing winter wheat. Pp. 73 - 76 in, Peairs, F. B., ed. Colorado Wheat Production Handbook, 2nd ed. Colorado Association of Wheat Growers, Lakewood, CO. 96 pp. |