ABSTRACT

This study was conducted in 2002 to evaluate the ovicidal properties of neonicotinoids against Helicoverpa zea (Boddie) in a field environment, located in Nash county, North Carolina. Newly laid (white) bollworm eggs were collected from leaves of cotton plants within respective treatments at 0, 1, and 2 days after insecticide application and transported to the laboratory for assessment of ovicidal and eclosion mortality. The neonicotinoids acetamiprid, imidacloprid, and thiamethoxam provided mortality for eggs present on the plants at application (0 DAT), comparable to that obtained with two ovicide standards, thiodicarb and lambda-cyhalothrin. Mortality of eggs deposited the night after application and collected 24 hr after application (1 DAT) dropped precipitously in all insecticide treatments, except thiodicarb. Egg mortality at 1 DAT was comparable for all neonicotinoids. For eggs collected at two day after application, ovicidal activity of the neonicotinoids had ceased and egg mortality in the standard treatments had declined to ca. 25%. This study confirmed ovicidal activity of the three neonicotinoids under field conditions; however ovicidal activity of neonicotinoids was ephemeral and not comparable to that of the ovicide standards.