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Biorationals for Management of Lepidopteran Pests of Fresh Market Sweet Corn 1999

Project Leader: R. W. Straub, Cornell’s Hudson Valley Laboratory

Abstract:

Shippers of fresh market sweet corn strive to maintain pests below a market threshold of 5% infested ears. Sweet corn pests in the Hudson Valley (European corn borer [ECB]; corn earworm [CEW]; and fall armyworm[FAW]), are currently controlled by pyrethroid or carbamate insecticides that generally provide excellent results. Much of the sweet corn in the region is treated by aircraft. Aerial applications are highly visible and raise environmental and public health concerns in the minds of some who reside in proximity to treated fields. It is unlikely that the practice will change in the near future, but concerns might be lowered if conventional insecticides were replaced by compounds that are reduced-risk or biorational in origin and activity. We reasoned that if biorational insecticides were being sprayed instead of 'hard' insecticides, such as pyrethroids, aerial application might be more readily accepted. Over two seasons of field experimentation, the relative efficacies of present and near-future biorationals (SpinTor® [spinosad]; Proclaim® [emamectin]; M-Pede® [soap]; Confirm® [tebufenozide]; Dipel® [Bacillus thuringiensis]; and Neemix® [azadiractin]) were determined in efforts to give them serious consideration for inclusion into NY management programs.

Results of this research provide information concerning 'soft' programs for producers of fresh market sweet corn--particularly useful in those areas of the state where applications of conventional insecticides are becoming socially problematic. Under the conditions of testing, biorational or reduced-risk insecticides were generally inferior to the standard pyrethroid (Warrior) insecticide. The exception was SpinTor (recently registered), which generally performed very well relative to the standard, and probably will become commonly used in sweet corn production. Other biorationals, if applied at twice the recommended application rate under low infestation conditions, appear to have sufficient efficacy for use in commercial sweet corn production — however, the cost would likely be prohibitive. At high infestation conditions, only SpinTor is comparable to the Warrior® standard. We have not performed experimental trials to evaluate decreased application intervals. Applying these materials more often may render them more efficacious, but again the cost-effectiveness is questionable. It is concluded that of the biorational insecticides evaluated, only SpinTor shows promise of being commonly used in fresh market sweet corn production.