Topical application of I to 4 micro-g of plumbagin, a napthoquinone from Plumbago zeylanica to the newly moulted 5th instar nymphs of Dysdercus cingulatus retarded growth and delayed metamorphosis in a dose-dependent manner. Metamorphosed adults possessed deformed wings. Treatment of the nymphs with higher doses of plumbagin inhibited moulting. Prothoracic gland cells of such insects were selectively stained blue-black. These observations suggest that plumbagin interferes with the function of prothoracic glands.
N. K. Joshi, Lathika, K. M., Banerji, A., and Chadha, M. S., “Effect of plumbagin on Growth and Development of Red Cotton Bug, Dydercus Koenigii”, vol. B54. Proc. Indian Natn. Sci. Acad., p. 43, 1988.