Submitted to: Environmental Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/4/1997
Publication Date: N/A
Citation: Interpretive Summary: The European corn borer is a major pest of corn in the Midwest costing farmers annually anywhere from $15 to $50 for every acre of corn. In addition to yield losses, pesticide loads to the environment due to this pest are substantial. Genetically-engineered corn hybrids (also called transgenic corn hybrids) will allow farmers to reduce insecticide applications and will help stabilize corn yields. These plants could lead to cleaner environments for producers' families and communities and could contribute substantially toward an overall goal of sustainable agriculture. Widespread use of transgenic plants, coupled with extensive control of insects on these plants, has many scientists concerned about corn borers becoming resistant to these plants. Most scientists favor resistance management programs that include corn borer refuge, that is, plants that support the growth of corn borers that are susceptible to transgenic corn. The intent is to reduce the frequency of resistant moths with an abundant number of susceptible moths. Reliable methods to attract corn borer adults to small grain crops could influence the production of susceptible moths. Also, aggregating moths into small well-defined areas could be useful for control purposes. In this study various planting combinations of oats and legumes, and barley and legumes were investigated. Highest number of corn borer adults were attracted to double-planted oats in one study and barley planted with alfalfa in another. Corn borer aggregation behavior increased with plant canopy. This information is useful to scientists and producers who wish to increase corn borer refuge for managing corn borer resistance to transgenic corn hybrids.
Technical Abstract: Reliable methods to attract adult European corn borers (ECB), Ostrinia nubilalis (Hubner) to small grain crops could be used in a resistance management program for delaying potential corn borer resistance to transgenic corn or could be used to aggregate moths into small well-defined areas for control purposes. The objective of this research was to determine whether small-grain crops could be managed to influence ECB aggregation behavior. In farmer-managed oats, Avena sativa (L.), more corn borer moths were attracted to high-density patches of oats compared with standard patches of oats; no difference was found between patches of high- density oats, and brome, Bromus spp. Numbers of ECB moths found in six barley, Hordeum vulgare (L.), and legume treatments and four oat treatments were significantly different. Barley planted with alfalfa, Medicago sativa (L.), attracted the highest number of ECB adults followed by barley planted dwith crimson clover, Trifolium incarnatum (L.), berseem, Trifolium alexandrinum (L.), black medic, Medicago lupulina (L.), barley alone, and lespedeza, Lespedeza stipulacea (Maxim.). Double-planted oats attracted the highest number of ECB adults followed by oats planted with crimson clover, oats planted with alfalfa and single-planted oats. Each of the studies suggest that there is a positive correlation between the tendency for moths to aggregate and canopy percentage.