Toxicity and Absorption of Azadirachtin, Diflubenzuron, Pyriproxyfen, and Tebufenozide after Topical Application in Predatory Larvae ofChrysoperla carnea(Neuroptera: Chrysopidae)

Abstract

Abstract Susceptibility of the generalist predator, the lacewing Chrysoperla carnea (Stephens), to the insect growth regulators azadirachtin, diflubenzuron, pyriproxyfen, and tebufenozide was tested in the laboratory. Third instars were topically treated with different doses of formulated materials of each compound by direct topical exposure. At maximum field-recommended dose, pyriproxyfen and tebufenozide were harmless to C. carnea, whereas azadirachtin and diflubenzuron were harmful (respective LD90s were 24.5 and 6.9 ng active ingredient [AI] per insect). At sublethal doses of azadirachtin and diflubenzuron, females laid fertile eggs, but azadirachtin caused a slight negative effect on oviposition. Pyriproxyfen and tebufenozide had no effect on oviposition and egg fertility. As a second approach of this study, toxicity data are discussed in relation to the rate of penetration and excretion after topical application. One hour after administration, ≈80% of pyriproxyfen had penetrated; whereas for diflube...