Toxicity of some juvenile hormone-active compounds forspodoptera littoralis boisd. larvae

Six juvenile hormone analogues, compounds 6–9550, 8–4314, and 20–3600 of Dr. R. Maag Ltd., Switzerland, and compounds ZR-512, ZR-515 and ZR-619 of Zoecon Corp., U.S.A., were tested against big and medium-size larvae ofS. littoralis Boisd. by topical application. Compounds 6–9550 and 8–4314 were slightly active against big larvae and inactive against medium-size larvae; ZR-512 was moderately active against big and inactive against medium-size larvae. The other three compounds caused 90% mortality in big larvae: 20–3600 at 20μg/larva and ZR-515 and ZR-619 at 5μg/larva. ZR-512 and ZR-619 were less toxic for medium-size larvae than for big larvae, whereas 20–3600 was about equitoxic for larvae of both sizes