Progress 10/13/09 to 09/30/12
Outputs
OUTPUTS: Over the course of the project, we researched factors influencing populations of soybean aphid, an invasive pest of soybeans. We also initiated research on slugs, the most important invertebrate pests of no-till soybean production in the mid-Atlantic region. And in the past year or so, we have begun exploring the influence of brown marmorated stink bug on soybeans in Pennsylvania. For soybean aphid, we determined that generalist predators (lady beetles, Orius, damsel bugs) typically prevent this pest from reaching economically significant populations. Some of our research indicates that control of aphids in soybean fields may be improved by planting genetically diverse cultivar mixtures in single fields rather than planting genetic monocultures as is the current standard. Genetically more diverse fields appear resist aphid colonization, but also harbor a more diverse natural enemy community that suppresses aphid populations. In a distinct project, we explored the role that sub-lethal doses of plant growth regulator herbicides play in flaring local aphid populations. These herbicides are volatile and they can drift to adjacent fields, stressing crop plants and making them more susceptible to herbivore colonization and less likely to harbor populations of natural enemies. Our findings appear to indicate that sub-lethal doses of some herbicides can exacerbate pest problems by flaring aphid populations. In our research with slugs, we have identified some of the factors contributing to slug outbreaks. We have also identified some beetle species that will eat slugs given the opportunity. These beetles are easily killed by insecticides, which may be indirectly contributing to slug outbreaks. We have identified cover crops species that help foster slug populations as well as a few that appear to suppress slugs in the subsequent soybean crop. PARTICIPANTS: John Tooker - Assistant Professor and member of S1039 TARGET AUDIENCES: Entomologist, Researchers, Extension Educators, Agricultural Industry Personnel PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Our research has provided basic and applied insight on the influences that contribute to outbreaks of herbivores in soybeans. Importantly, our discoveries are relevant to other crop-pest species interactions. Because we communicating our findings to extension educators and our agricultural clientele, we have provided growers of Pennsylvania with current information on the status of soybean herbivores and their management. Our recommendations to use an Integrated Pest Management framework to help avoid unnecessary insecticide applications has facilitated harnessing natural enemy populations, which can help control pest populations, saving growers money they would usually spend on insecticides. Much of our work with slugs has been inspired by interactions with Pennsylvania farmers; thus, our work is empowered by clientele that wants the research conducted. This approach was vital in adoption of our recommendation, and will be important as our work with stink bugs grows.
Publications
- Douglas, M. R. and J. F. Tooker. 2012. Slug (Mollusca:Agriolimacidae, Arionidae)ecology and management in no-till field crops, with an emphasis on the Mid-Atlantic region. Journal of Integrated Pest Management 3:C1-C9.
- Cui, L. L., F. Francis, Y. Liu, S. Heuskin, G. Lognay, J. Dong, J. Chen, C. Bragard, J. F. Tooker, and Y. Liu. 2012. E-beta-Farnesene syngergizes the influence of an insecticide to improve control of cabbage aphids in China. Crop Protection 35:91-96.
- Tooker, J. F. and S. D. Frank. 2012. Genotypically diverse cultivar mixtures for insect pest management and increased crop yields. Journal of Applied Ecology 49:974-985.
|
Progress 10/01/10 to 09/30/11
Outputs
OUTPUTS: During the reporting period, we continued several research experiments to explore factors influencing populations of soybean aphid, an invasive pest of soybeans and a few other crops that has developed into one of the most important pests of soybeans in North America. We continued work on slugs, important pests of no-till soybean production in the mid-Atlantic region. We have also begun working with brown marmorated stink bug, which is on its way to becoming the most important pest of soybeans in Pennsylvania. Soybean aphid was discovered in Pennsylvania in 2001, but in 2003, 2005, 2007, and 2009 populations of aphids exploded in soybean fields, causing significant yield reductions and use of insecticides by farmers to protect their crops. In non-outbreak years, naturally occurring generalist predators including syrphid larvae, lacewings, ladybird beetles, damsel bugs and minute pirate bugs control the populations of aphid that colonize soybean fields. Our research strives to understand why natural enemy succeed or fail to control aphid colonizing aphid populations. Our research has characterized the community of predaceous insect species that colonize soybean fields in Pennsylvania. Further, our findings indicate that improved control of aphids in soybean fields may be facilitated by planting fields with more than one genetic variety. These more diverse fields appear to better resist aphid colonization, but also harbor a more diverse natural enemy community that will be available to kill and eat aphids as their populations arrive and grow. In a distinct project, we are exploring the role that herbicides can plant in facilitating colonization of soybean fields by herbivorous insect populations, including soybean aphids and leaf hoppers. Some types of herbicides are volatile and their vapor drift can move from fields where they were applied to adjacent crop fields, stressing those plants and making them more susceptible to herbivore colonization and less likely to harbor populations of natural enemies. Our findings appear to indicate that sub-lethal doses of some herbicides can exacerbate pest problems by flaring aphid populations. In our research with slugs, we continue to strive to understand factors influencing slug populations. Slugs are quite difficult to control in soybean fields where conservation tillage approaches have been adopted. Compounding problems is that growers have access to few control options. We are studying the populations of natural enemies harbors in soybean fields treated with insecticides and those that do not receive control products to understand if excessive insecticide use facilitates slug populations by knocking back natural enemy populations. PARTICIPANTS: John Tooker - Assistant Professor and member of S1039. TARGET AUDIENCES: Entomologist, Researchers, Extension Educators, Agricultural Industry Personnel. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Our research contributes to an improved understanding of influences that govern outbreaks of herbivores in soybean fields. Importantly, our discoveries in soybean fields will be relevant to other crop-pest species interactions. By communicating our findings via our extension programming, we have brought our work to farmers that can consider the results and change their farming tactics accordingly to better harness natural enemies to control their pest populations. IPM (integrated pest management) remains the best approach for combating insect problems in grain and forage production. Our recommendations for harnessing natural enemy populations to help control pest populations agree with the central principles of IPM that stress minimizing pesticide use to allow natural processes to help contribute to pest control. Much of our slug research has been directed by farmer input, so our work is empowered by the willingness of growers to provide insight and feedback on our findings. This approach will continue to be vital as we begin working with brown marmorated stink bug in earnest.
Publications
- No publications reported this period
|
Progress 10/01/09 to 09/30/10
Outputs
OUTPUTS: During the reporting period, we established several research experiments to understand factors contributing to soybean aphid control. Since 2001, soybean aphid has been the most important insect pest of soybeans grown in Pennsylvania. During odd-numbered years (e.g., 2005, 2007, 2009) soybean aphid populations outbreak, causing yield reductions and necessitating many growers to protect their fields with insecticides. In even-numbered years, natural enemies, such as ladybird beetles, lacewings and syrphid larvae, and predaceous bugs keep aphid populations in check. Our experiments seek to understand factors contributing to natural enemy success or failure. Our efforts have defined the suite of natural-enemy species that are active in Pennsylvania soybean fields. Moreover, the results appear to indicate that soybean fields planted with one genetic variety may not be colonized by as diverse a natural enemy community as those planted with several genetic varieties. In another project, we are learning that low levels of herbicide drift from adjacent fields have strong potential to stress plants and make them more prone to infestation by soybean aphid. We are also working to better manage slugs in soybean production. Slugs are extremely challenging to manage in no-till soybean fields and few commercial control options are available. We have begun a line of inquiry to better understand the feeding preferences of slugs and the natural enemies that will feed upon slugs. A better understanding of slug feeding preferences may facilitate design of cropping rotations that suppress slug populations. Understanding natural enemies of slugs will help direct efforts to minimize the impact of cropping tactics detrimental to populations of these beneficial arthropod species. PARTICIPANTS: John Tooker - Assistant Professor and member of S1039. TARGET AUDIENCES: Entomologist, Researchers, Extension Educators, Agricultural Industry PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Our research efforts are contributing to a better understanding of the factors that contribute to better natural-enemy mediated control of soybean aphid. Importantly the results are applicable to other crop-aphid systems. Through our extension efforts, we have shared our research findings and conveyed to growers the best ways to harness natural enemy-mediated control in their soybean fields. Integrated pest management remains the best framework for tackling insect outbreaks in field crop production and our recommendations for maximizing natural enemy populations align well with tenets of IPM that stress avoidance of prophylactic insecticide applications and/or calendar sprays and reliance on scouting and economic thresholds. For our work with slugs in no-till soybeans, we have begun sharing the information we are learning at extension meetings to establish a dialogue with growers about slugs control options they feel are successful. Growers are contributing to the dialogue and appear to feel empowered by the opportunity to shape research that will benefit their production systems.
Publications
- No publications reported this period
|
|