Lifestage Specific Mortality Induced by a Combination of Ethion and Crop Oil on the Sweetpotato Whitefly in the Greenhouse, Summer, 1989

Abstract

Abstract Mortality of adults, crawlers hatching from treated eggs, small and large nymphs, and pupae were evaluated following treatment with a commercial product containing ethion and crop oil. All tests were conducted using two-leafed plants. To evaluate toxicity to adults, plants were sprayed with the insecticidal preparations. When the sprays had dried, leaves were excised and the petioles of each were placed individually in water-filled vials in 34 oz screen-ventilated plastic containers. Twenty-five adults were caged on each of four leaves for each treatment and mortality was evaluated after the containers had been held 2 d in a room at ca. 27°C. To evaluate toxicity to the immature stages, plants were exposed 24 h to adults. Two, two-leaved plants with 25 eggs per leaf were sprayed for each treatment the same d that adults were removed. The no. of crawlers that died as they exited the eggs or that died in close proximity to the eggs were recorded a wk later. The small amt of morality that was observed in the egg stage was added to crawler mortality. Other plants were held until either small nymphs, large nymphs, or pupae were present. Two two-leaved plants with 25 individuals of the desired lifestage per leaf were sprayed for each treatment. When the individuals on the check had developed to the next lifestage, mortality of the treated lifestage was evaluated.