A Genetically-Modified Bacillus thuringiensis Product Effective for Control of the Fall Armyworm (Lepidoptera: Noctuidae) on Corn

J. N. All, J. D. Stancil, T. B. Johnson, R. Gouger


ECX9399, a variant of strain EG2348 (the active ingredient of the bioinsecticide CondorĀ®) of Bacillus thuringiensis (Berliner) (Bt) subspecies kurstaki was developed by recombinant DNA technology by Ecogen Inc. This strain showed greater control of fall armyworm, Spodoptera frugiperda (J. E. Smith), infestations in whorl stage corn, Zea mays L., than other Bt products in field tests conducted in Georgia, Mississippi and Florida during 1993. Control by EC9399 was greatest in Mississippi, where a 4-day spray interval (total of 3 sprays) was used and least in Georgia, where a 7-day schedule (total of 3 sprays) was maintained. The new genetically-modified Bt product had comparable efficacy (decrease in larval number on plants and reduced defoliation) to methomyl, which was used at commercial rates as a conventional insecticide standard at the 3 locations.

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