The effects of topically-applied sublethal doses of carbofuran and carbaryl on oviposition and longevity of Diabrotica virgifera LeConte females were studied. At application rates representing very small percentages of their respective LD50 values, females treated with either insecticide oviposited significantly more and lived significantly longer than did control females. Carbofuran enhanced these phenomena more consistently than did carbaryl. No explanations are suggested as to why the carbamate insecticides tested stimulated oviposition and extended longevity.