Insect growth regulatory activity of naturally occurring quinones and their derivatives in Dysdercus koenigii Fabr. (Hem., Pyrrhocoridae)

Plumbagin, a naphthoquinone occurring in the plants belonging to Plumbago s p. is known to have insect growth disrupting activities. In the present stu dy, a comparative evaluation of bioactivities of related naphthoquinones. j uglone and menadione and benzoquinones, 2,6-dimethylbenzoquinone and 2,3,6- trimethylbenzoquinone along with 2,6-dimethylhydroquinone have been underta ken using Dysdercus koenigii. The LD50 values of the compounds showed wide variation. Although all the test compounds disrupted the normal growth at s ublethal doses, 2.6-dimethylbenzoquinone and menadione showed activity at l ow doses.