The cluster bug (Agonoscelis pubescens) is a major pest of Sorghum bicolor and many other crops in Sudan. Despite its costly chemical control, the pest retains more or less similar trend every year. This advocated the search for effective, cheap and safe alternatives. Hence, laboratory experiments were carried out to evaluate the insecticidal potentiality of Datura innoxia leaf extracts compared with a standard insecticide. Three extracts (water, ethanol and hexane) were studied concerning their application routes (spraying, dipping and filter paper methods) and bioassays against the adult A. pubescens. Mortality levels were recorded at different intervals (2, 3, 5 and 7days), post treatments. The results revealed that spraying of bugs on host plant gave better effects than the other application methods. The leaf hexane extract exerted significantly the highest mortality levels as compared with the other extracts, though was exceeded by the insecticide. In all extracts, the mortality rates generally increased in response to concentration and exposure time. Moreover, the hexane extract also manifested a hormonal effect on the pest emerged in deformed hind legs. In conclusion, the study proved variable biocidal activities of D. innoxia, and invites more research to isolate and characterize its active compounds particularly of hexane extract for proper assessment as natural biocides.

Keywords: Agonoscelis pubescens; Datura innoxia; bioassays; mortality effect; hormonal effect.