Progress 08/01/08 to 07/31/13
Outputs
Target Audience: Growers, crop consultants, agribusiness employees, Extension and other governement agency staff, pesticide applicators Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Four graduate students have been involved in the research reported under this project. How have the results been disseminated to communities of interest? Research reports have been disseminated through Extension workshops, newsletter articles, and through online media. Research results have been presented at scientific society meetings (Entomological Society of America). What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
An economic injury level was developed on field corn for western bean cutworm. Improved sampling methods were developed for western bean cutworm egg masses, and based on this a speed scouting mobile app was developed for binomial sequential sampling of eggs in corn. The relationship between western bean cutworm moth flight and degree-days was modeled. This will enable more accurate prediction of moth flight periods and will allow better timing of egg mass sampling. Studies were conducted in 2013 to study the seaonal occurrence of Dectes stem borer in Nebraska soybeans. This data will be used to develop degree-day models for Dectes oviposition, and to develop statistically valid sampling plans for Dectes in soybeans. A third year of sampling was conducted to describe the stink bug species complex and its seasonal occurrence in Nebraska corn and soybean.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2013
Citation:
Paula-Moraes, S., T.E. Hunt, R.J. Wright, G.L. Hein, & E. E. Blankenship. 2013. Western bean cutworm survival and development of economic injury levels and economic thresholds in field corn. J. Econ. Entomol. 106: 1274-1285.
- Type:
Journal Articles
Status:
Published
Year Published:
2011
Citation:
Paula-Moraes, S., E.C. Burkness, T.E. Hunt, R.J. Wright, G.L. Hein, W.D. Hutchison. 2011. Cost-effective Binomial Sequential Sampling of Western Bean Cutworm, Striacosta albicosta (Lepidoptera: Noctuidae), Egg Masses in Corn. J. Econ. Entomol. 104(6):1900-1908
- Type:
Other
Status:
Published
Year Published:
2012
Citation:
Paula-Moraes, S., E.C. Burkness, T.E. Hunt, R.J. Wright, G.L. Hein, W.D. Hutchison. 2012. Western bean cutworm speed scouting spreadsheet. Extension Circular 1585. University of Nebraska Extension, Lincoln NE
- Type:
Journal Articles
Status:
Published
Year Published:
2012
Citation:
Tirosele, B., T. E. Hunt, R. Wright, E. E. Blankenship, J. E. Foster. 2012. The soybean aphid, Aphis glycines: Population dynamics on edamame soybeans in Nebraska, USA. African J. of Agric. Res. 7(44): 5912-5918
- Type:
Journal Articles
Status:
Published
Year Published:
2010
Citation:
Hutchinson, W. D., E. C. Burkness, P. D. Mitchell, R. D. Moon, T. W. Leslie, S. J. Fleischer, M. Abrahamson, K. L. Hamilton, K. L. Steffey, M. E. Gray, R. L. Hellmich, L. V. Kaster, T. E Hunt, R. J. Wright, K. Pecinovsky, T. L. Rabaey, B. R. Flood, and E. S. Raun. 2010. Areawide suppression of European corn borer with Bt maize reaps savings to non-Bt maize growers. Science Vol. 330, Issue 6001 pp. 222-225
- Type:
Journal Articles
Status:
Published
Year Published:
2010
Citation:
Stilwell, A. R., R. J. Wright, T. E. Hunt & E. R. Blankenship. 2010. Degree-day Requirements for Alfalfa Weevil (Coleoptera: Curculionidae) Development in Eastern Nebraska. Environ. Entomol. 39: 202-209
- Type:
Journal Articles
Status:
Published
Year Published:
2009
Citation:
Brust, M. L., W. W. Hoback, and R. J. Wright. 2009. Apparent hybridization between Trimeratropis agrestis and Trimeratropis maritime in a recently disturbed habitat. J. Kansas Entomol. Soc. 82: 215-222
- Type:
Other
Status:
Published
Year Published:
2008
Citation:
Brust, M. L., W. W. Hoback & R. J. Wright. 2008. The Grasshoppers of Nebraska (Orthoptera: Acrididae and Romaleidae), Extension Book 3, University of Nebraska Extension, Lincoln NE, 135 pp.
- Type:
Journal Articles
Status:
Published
Year Published:
2009
Citation:
Brust, M. L., W. W. Hoback, and R. J. Wright. 2009. Degree-day requirements for eight economically important grasshoppers (Orthoptera: Acrididae) in Nebraska using field data. Environ. Entomol. 38: 1521-1526
|
Progress 10/01/11 to 09/30/12
Outputs
OUTPUTS: Western bean cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), is a native pest of dry beans (Phaseolus vulgaris L.) and corn (Zea mays L.) in the western and central United States. Since 2000, outbreaks of S. albicosta occurred throughout the north central region of the United States and Canada, suggesting an easterly expansion of the pest's range. As a result of larval feeding damage inside corn ears, S. albicosta has a narrow treatment window; thus, early detection of the pest in the field is essential, and egg mass sampling is recommended. Three action thresholds for field and sweet corn are currently used by crop consultants, including: 4% of plants infested with egg masses on sweet corn in the silking-tasseling stage; 8% of plants infested with egg masses on field corn with 95% of corn tasseled; and 20% of plants infested with egg masses on field corn during mid-milk-stage corn. The current monitoring recommendation is to sample 20 plants at each of five locations per field (100 plants total). To develop a more cost-effective sampling plan for S. albicosta egg masses, several alternative binomial sampling plans were developed using Wald's sequential probability ratio test, and validated using Resampling for Validation of Sampling Plans (RVSP) software. The benefit-cost ratio was also calculated and used to determine the final selection of sampling plans. A spreadsheet and mobile app were developed to increase adoption of this sampling plan. In corn, the economic impact is caused by ear feeding by fourth and fifth instar larvae. Information on western bean cutworm biology, ecology, and economic impact is relatively limited and a refinement of economic injury levels (EIL) and economic thresholds (ET) are required for more effective management decision-making. Studies were conducted across three ecoregions of Nebraska to characterize the western bean cutworm egg and larval survival and to develop Economic Injury Levels (EIL) and the Economic Thresholds (ET). The calculations of EIL and ET incorporated the dynamics of corn price, management cost, and pest survival. Larval survival observed across three locations in Nebraska was incorporated in ET calculations, and was expressed as percentage of plants with at least one egg mass. PARTICIPANTS: Silvana Paula-Moraes, an entomology researcher from Embraba-Brazil, worked on this project under a fellowship from Brazil, as part of her Ph. D. program at UNL. Collaborators included E. Burkiness and W. Hutchison from Univ. of Minnesota. Other collaborators at UNL include T. Hunt, G. Hein and E. Blankenship. TARGET AUDIENCES: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Based on final sampling plans selected for each action threshold, the average sample number required to reach a treat or no-treat decision ranged from 38 to 41 plants per field. This represents a significant savings in sampling cost over the current recommendation of 100 plants. Cost-effective sampling plans are more likely to be adopted. The results demonstrated low larval survival of this species (about 5%). The mean yield loss for one western bean cutworm larva per plant was 945.52 kg/ha (15.08 bu/acre), based on 74,100 plants/ha. Larval survival observed across three locations in Nebraska was incorporated in ET calculations, and was expressed as percentage of plants with at least one egg mass. Improved economic thresholds will lead to better targeted insecticide applications to situations where economic return to the grower is most likely.
Publications
- Paula-Moraes, S., E.C. Burkness, T.E. Hunt, R.J. Wright, G.L. Hein, W.D. Hutchison. 2011. Cost-effective Binomial Sequential Sampling of Western Bean Cutworm, Striacosta albicosta (Lepidoptera: Noctuidae), Egg Masses in Corn. J. Econ. Entomol. 104(6):1900-1908. Paula-Moraes, S., E.C. Burkness, T.E. Hunt, R.J. Wright, G.L. Hein, W.D. Hutchison. 2012. Western bean cutworm speed scouting spreadsheet. Extension Circular 1585. University of Nebraska Extension, Lincoln NE Tirosele, B., T. E. Hunt, R. Wright, E. E. Blankenship, J. E. Foster. 2012. The soybean aphid, Aphis glycines: Population dynamics on edamame soybeans in Nebraska, USA. African J. of Agric. Res. 7(44): 5912-5918.
|
Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: To develop a more cost-effective sampling plan for western bean cutworm, Striacosta albicosta, egg masses in corn, several alternative binomial sampling plans were developed using Wald's sequential probability ratio test, and validated using Resampling for Validation of Sampling Plans (RVSP) software. The benefit-cost ratio was also calculated and used to determine the final selection of sampling plans. The development and distribution of western bean cutworm (WBC) larvae on the corn plant was characterized in the field and the effect of different corn tissues on larval survival and development was investigated in lab. Studies were conducted at the UNL Haskell Agricultural Laboratory, Concord, NE during 2011. The larval movement study was conducted as a randomized complete block design with six replicates. The treatments were different corn growth stages: (1) pre-tassel; (2) tassel; and (3) post-tassel stage. The infestation was artificial and the plant was divided in five zones: tassel; above ear; first ear; second ear; and below ear zone. Each zone was inspected for the presence of larvae (destructive sampling in each plot). In the tassel zone, Berlese funnels were used to recover larvae. The corn tissue feeding experiment was conducted in growth chambers (25 degrees C and 24h light). Experimental design was a completely randomized design with three reps. The treatments were different corn tissues (early whorl, late whorl, tassel, silk, pollen and silk + pollen). Stink bugs were monitored weekly (June to November 2011) at three agricultural research stations in Nebraska located at Clay Center, Ithaca, and Concord. The research objectives were to delineate the species composition and population dynamics of pentatomids in wheat, soybean, corn, alfalfa, and weeds. This information has been disseminated in extension newsletters and workshops in Nebraska, as well as presentations at Entomological Society of America meetings. PARTICIPANTS: Co-investigators include Tom Hunt, Gary Hein, Erin Blankenship and Jeffrey Bradshaw, University of Nebraska-Lincoln and William Hutchison and Eric Burkness, University of Minnesota. Partial support of stink bug research was provided by Nebraska Soybean Board. Two graduate students, Zaki Wan Mamat and Silvana V. Moraes, are conducting doctoral dissertation research as part of this project. TARGET AUDIENCES: Nebraska corn and soybean growers, crop consultants and agribusiness personnel are target audiences for this research. Information from this research has been provided to target audiences through extension workshops, extension publications and newsletters. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Based on final sampling plans selected for each action threshold (4, 8 and 20 percent of plants with one or more western bean cutworm egg mass), the average sample number required to reach a treat or no-treat decision ranged from 38 to 41 plants per field. More cost-effective sampling plans will make it easier for people to make western bean cutworm treatment decisions based on economic thresholds in corn. Larval western bean cutworm feeding was greatest on tassel tissue in the late whorl stage . In field conditions the initial larval instars were concentrated in upper part of the plant. Several species of stink bugs were detected in Nebraska, including Euschistus variolarius (Palisot de Beauvois), Thyanta accerra McAtee, Cosmopepla lintneriana Kirkaldy, Podisus maculiventris (Say), Acrosternum hilare (Say), and Holcostethus limbolarius (Stal). Overall, E. variolarius was the most abundant species followed by T. accerra. The infestation of A. hilare on soybeans started in early September. However, the peak densities of other stink bugs were observed in August and September. Studies in 2011 indicated that 78 percent of E. variolarius eggs collected from corn and soybean fields were parasitized by parasitic wasps.
Publications
- No publications reported this period
|
Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: Transgenic maize engineered to express insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) has become widely adopted in U.S. agriculture. In 2009, Bt maize was planted on more than 22.2 million hectares, constituting 63% of the U.S. crop. Using statistical analysis of per capita growth rate estimates, we found that areawide suppression of the primary pest Ostrinia nubilalis (European corn borer) is associated with Bt maize use. Cumulative benefits over 14 years are an estimated $3.2 billion for maize growers in Illinois, Minnesota, and Wisconsin, with more than $2.4 billion of this total accruing to non-Bt maize growers. Comparable estimates for Iowa and Nebraska are $3.6 billion in total, with $1.9 billion for non-Bt maize growers. The alfalfa weevil, Hypera postica (Gyllenhal), is a serious, yet sporadic defoliator of alfalfa, Medicago sativa L., in Nebraska. A 2-yr study was conducted to test for variation in degree-day requirements by location in eastern Nebraska. Sampling took place along a latitudinal gradient in three regions of eastern Nebraska. Three fields were sampled in each region during the 2 yr of the study. Alfalfa weevil larval degree-day requirements were found to vary by latitude in eastern Nebraska. Alfalfa weevil larvae were discovered in southern regions after fewer developmental degree-days had accumulated than in fields in the northern regions. Alfalfa weevils may be more damaging to alfalfa in southern regions than in northern regions of eastern Nebraska because they emerge earlier relative to alfalfa growth. PARTICIPANTS: W. D. Hutchinson, E. C. Burkness, P. D. Mitchell, R. D. Moon, T. W. Leslie, S. J. Fleischer, M. Abrahamson, K. L. Hamilton, K. L. Steffey, M. E. Gray, R. L. Hellmich, L. V. Kaster, Thomas E. Hunt, Robert J. Wright, K. Pecinovsky, T. L. Rabaey, B. R. Flood, and E. S. Raun participated in the Bt maize study. A. R. Stilwell, Robert J. Wright, Thomas E. Hunt, and E. E. Blankenship participated in the alfalfa weevil study. A. R. Stilwell conducted this research as part of her M. S. thesis degree program at UNL. Brust, M. L., W. W. Hoback, and R. J. Wright participated in the grasshopper study. M. Brust conducted this research as part of his Ph. D. dissertation program at UNL. TARGET AUDIENCES: Crop producers, crop consultants, seed and pesticide suppliers, pesticide applicators, research and extension faculty and staff PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Documentation of the areawide suppression of European corn borer across the midwestern U.S. and its economic impact affirm theoretical predictions of pest population suppression and highlight economic incentives for growers to maintain non-Bt maize refugia for sustainable insect resistance management. Knowledge of variation of degree-day requirements for alfalfa weevil larval development in eastern Nebraska allow us to provide more accurate, site-specific recommendations to alfalfa growers on when to scout for alfafa weevil larvae, and take timely management actions if warranted.
Publications
- Hutchinson, W. D., E. C. Burkness, P. D. Mitchell, R. D. Moon, T. W. Leslie, S. J. Fleischer, M. Abrahamson, K. L. Hamilton, K. L. Steffey, M. E. Gray, R. L. Hellmich, L. V. Kaster, T. E Hunt, R. J. Wright, K. Pecinovsky, T. L. Rabaey, B. R. Flood, and E. S. Raun. 2010. Areawide suppression of European corn borer with Bt maize reaps savings to non-Bt maize growers. Science Vol. 330, Issue 6001 pp. 222-225.
- Stilwell, A. R., R. J. Wright, T. E. Hunt & E. R. Blankenship. 2010. Degree-day Requirements for Alfalfa Weevil (Coleoptera: Curculionidae) Development in Eastern Nebraska. Environ. Entomol. 39: 202-209.
- Brust, M. L., W. W. Hoback, and R. J. Wright. 2009. Apparent hybridization between Trimeratropis agrestis and Trimeratropis maritime in a recently disturbed habitat. J. Kansas Entomol. Soc. 82: 215-222.
|
Progress 10/01/08 to 09/30/09
Outputs
OUTPUTS: Studies were conducted on the species identity and seasonal occurrence of grasshoppers in Nebraska. The results were summarized in an extension book (Brust et al. 2008) which was disseminated to Nebraska Extension Educators and USDA-APHIS personnel in the western region. Studies were conducted at Clay Center on the species identity, seasonal occurrence and control of stink bugs in Nebraska soybeans as part of a study at three sites in eastern Nebraska. Studies were conducted at Clay Center, Concord and Scottsbluff to describe the economic injury level, and larval survival and behavior of western bean cutworms on corn. PARTICIPANTS: Grasshopper studies were conducted in cooperation with Dr. W. Wyatt Hoback, University of Nebraska-Kearney, with funding from USDA-APHIS. Stink bug studies were conducted in cooperation with Dr. Tom Hunt, UNL Entomology Deparment, Haskell Ag Laboratory, Concord NE, with funding from the Nebraska Soybean Board, and Bayer Crop Sciences. Western bean cutworm studies were conducted in cooperation with Dr. Tom Hunt, UNL Entomology Department, Haskell Ag Laboratory, Concord NE, Dr. Gary Hein, UNL Entomology Department, and Dr. Tamra Jackson, UNL Plant Pathology Department, with funding from USDA-CSREES. Matt Brust conducted his doctoral research on the grasshopper project and graduated in August 2008. Silvana Moraes is currently a Ph. D. student at UNL working on the western bean cutworm project, with support from EMBRAPA. TARGET AUDIENCES: Work conducted under this project has application to crop producers, ranchers, crop advisors, government agency personnel, and pesticide and seed company personnel. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Better understanding of the species identity and seasonal occurrence of grasshoppers in Nebraska will contribute to their management, as grasshopper species vary greatly in their seasonal occurrence and economic importance on different crops. Stink bugs are becoming more common on Nebraska field crops, but little is known of their seasonal occurrence and economic impact in the north central region. Understanding which species occur on which crops and their seasonal occurrence and economic impact are essential to develop management programs to reduce their damage to crop producers. Western bean cutworms have recently increased their range across the eastern corn belt, and infest a much larger area than previously reported. Little recent research has been conducted on their economic impact, seasonal occurrence and distribution. This information is needed to develop research-based integrated pest management programs for this pest.
Publications
- Brust, M. L., W. W. Hoback & R. J. Wright. 2008. The Grasshoppers of Nebraska (Orthoptera: Acrididae and Romaleidae), Extension Book 3, University of Nebraska Extension, Lincoln NE, 135 pp.
- Brust, M. L., W. W. Hoback, and R. J. Wright. 2009. Degree-day requirements for eight economically important grasshoppers (Orthoptera: Acrididae) in Nebraska using field data. Environ. Entomol. 38: 1521-1526.
|
Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: Studies on the seasonal occurrence, larval dispersal and damage potential of the western bean cutworm on corn were conducted at Clay Center, Concord and Scottsbluff, NE. The seasonal occurrence of stink bugs in corn and soybeans were monitored using pheromone traps and light traps at Clay Center and Concord NE. The seasonal occurrence of Agromyza parvicornis, the corn blotch leafminer, was monitored using sticky traps in a commercial corn field in south central Nebraska. This usually rare insect has been increasingly causing visual damage to corn in south central Nebraska; very little is known about its' biology. A replicated trial was conducted to evaluate labelled and experimental seed treatment insecticides against the soybean stem borer, Dectes texanus texanus, a native insect which has been building in numbers and causing observable damage in south central Nebraska. PARTICIPANTS: Dr. Tom Hunt, Dr. Gary Hein, and Dr. Tamra Jackson are collaborators on the western bean cutworm project. Dr. Tom Hunt and I collaborate on the soybean insect studies described. A Ph. d. graduate student participates in the western bean cutworm project. TARGET AUDIENCES: These studies are targeted at grain producers, crop advisors, and seed and pesticide industry employees in Nebraska and the north central region. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Better understanding of the seasonal occurrence of the corn blotch leafminer will allow better targeting of sampling and control efforts by corn growers in Nebraska. Initial data from 2008 are consistent with past studies at Kansas State University which indicate that fipronil seed treatments provide season long control of soybean stem borer larvae. This treatment is not yet labelled for use on soybeans. Other studies are in their first year and outcomes and impacts cannot yet be described.
Publications
- M. L. Brust, W. W. Hoback, and R. J. Wright. 2008. A Synopsis of Nebraska Grasshopper Distributions. J. Kansas Entomological Society 81: 208-255.
- M. L. Brust, W. W. Hoback & R. J. Wright. 2008. A Review of the genus Chortophaga Among Nebraska Populations: Questioning the Validity of Chortophaga australior Rehn and Hebard. Journal of Orthoptera Research 17: 101-105.
- Carstens, J.D., F.P. Baxendale, T.M. Heng-Moss and R.J. Wright. 2008. Predation of the chinch bug, Blissus occiduus Barber (Hemiptera: Blissidae) by Geocoris uliginosus (Say) (Hemiptera: Lygaeidae). J. Kansas Entomol. Soc. (In Press).
|
|