Dosage-Mortality Data for Five Insecticides on Three European Corn Borer Ecotypes

Dosage-mortality studies were conducted to develop baseline dosage-mortality data for 5 insecticides topically applied to 3rd in stars of Ostrinia nubilalis (Hubner) representing the northern, central, and southern ecotypes of this insect in the U.S. For each ecotype, the relative insecticide toxicity on the basis of LDso values in declining order was: carbofuran>-fonofos>phorate>carbaryl>toxaphene. The Central ecotype was significantly ( P = 0.05) more tolerant to carbofuran and fonofos as compared with the northern and southern ecotypes. No differential responses to carbaryl, phorate, and toxaphene were detected among ecotypes.