On-Farm Evaluation of Beauveria bassiana for Long-Term Suppression of the European Corn Borer in Midwestern Cropping Systems

On-Farm Evaluation of Beauveria bassiana for Long-Term Suppression of the European Corn Borer in Midwestern Cropping Systems

Summary

The European Corn Borer (ECB), Ostrinia nubilalis, is a serious pest of corn in the Corn Belt, causing estimated yield losses in the Midwest from $50 to $120 per hectare of corn (est. $20-$50 per acre). With increasing restrictions on insecticides, the call for sustainable agriculture, federal mandates for less surface and ground water remediation and requirements to have 70 percent of crop land under IPM by the year 2000, there is a greater need for innovative methods to control this pest.

In 1996 and 1997 we conducted on-farm research, with cooperators from the Practical Farmers of Iowa (PFI), in a biointensive approach to managing this insect. In 1997 we also conducted research on an additional farm not affiliated with PFI. An entomogenous fungus, Beauveria bassiana, that develops a unique endophytic relationship with the corn plant, was employed in this management technique. In 1996 the fungus was applied to corn at the whorl stage, pollen-shedding stage and at post-harvest to manage the first generation, second generation and overwintering ECB. In 1997 the fungus was applied only at the whorl stage of plant growth. In small field plots B. bassiana has been shown to reduce plant feeding during the growing season, and B. bassiana present at harvest kills overwintering larvae, reducing the following year’s population. Once this fungus is placed in the ecosystem it will maintain itself in the soil, crop residue and the growing corn plant.

At this time in our research we do not know how often B. bassiana must be applied to the ecosystem to maintain the ECB below an economic threshold. If this scenario is practiced over a wide area it may be possible to maintain the ECB below an economic threshold without use of synthetic chemical insecticides. This approach may completely transform ECB management. Primary benefits of this proposed research are: 1) reduced producer dependency and exposure to synthetic insecticides; 2) less environmental contamination; and 3) a contribution to long-range goals of reduced environmental and ecological disruption from overuse of insecticides. North Central Region SARE 1997 Annual Report.

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