COMPARISON OF CHEMIGATED AND AERIALLY-APPLIED CHLORPYRIFOS AND FENVALERATE FOR CONTROL OF EUROPEAN CORN-BORER (LEPIDOPTERA, PYRALIDAE) LARVAE

Aerial and overhead center-pivot irrigation system (chemigated) applic ations of chlorpyrifos 4 emulsifiable concentrate (EC) and fenvalerate 2.4EC significantly reduced numbers of first- and second-generation E uropean corn borer, Ostrinia nubilalis Hubner, larvae in field corn, Z ea mays L. The number of first-generation O. nubilalis larvae, pupae, or cavities per plant in plots chemigated with chlorpyrifos in 1984 wa s significantly less than in plots where chlorpyrifos was applied aeri ally. A similar trend was observed for fenvalerate in 1985. No signifi cant differences among application methods were observed for second-ge neration O. nubilalis treatments. Chlorpyrifos and fenvalerate were ef fective O. nubilalis control agents but efficacy differences between t hese two insecticides were variable. Corn yields did not vary signific antly among application methods.