Morphogenetic Effects of the Juvenoid Active Compound from Blumea laccinata (Compositae) on Dysdercus cingulatus

Laboratory experiment was carried out to assess the effect of Thin Layer Chromatography (TLC) purified component from a commonly available weed, the Blumea lacciniata on Dysdercus cingulatus, the red cotton bug. Last instar nymphs and newly emerged insects were treated with the active component and effect of internal reproductive organs namely, testes, seminal vesicle, vasa deferentia and accessory as well as male genitalia have been observed. Different degree of deformities has been observed on male reproductive organs of test insect as normally found with juvenoid action. Parameres which are the main components of the male external genitalia also showed abnormality and even a slight variation in parameres inhibits mating, indicating that the purified extract of B. laccinata was effective against the mating behaviour and external genitalia of male D. cingulatus. The study further confirmed juvenoid action of TLC purified component.