TOXICOLOGICAL STUDIES ON THE LATEX OF THE USHER PLANT CALOTROPIS-PROCERA (AIT.) IN SAUDI-ARABIA - IV - EFFECTS OF PARTLY PURIFIED USHER LATEX AND OF THE POISON GLAND SECRETION OF THE USHERHOPPER, POEKILOCERUS-BUFONIUS KLUG ON THE DESERT LOCUST, SCHISTOCERCA-GREGARIA FORSKAL - (ORTHOPTERA, ACRIDIDAE)

The partially purified latex (PPL) of the usher plant, Calotropis proc era (Air), as well as the cardiac glycosides-rich poison gland secreti on (PGs) of the usherhopper, Poekilocerus bufonius Klug have been test ed for their toxicity on the desert locust, Schistocerca gregaria Fors kal by injecting them into the haemocoel of the locust. Both proved to xic to the locust, but PGs was far more so than PPL. The former caused 100% mortality in the locust at all dose levels used, but the mortali ty rate caused by the latter was proportional to the dose used. The po tential of both PPL and PGs as pesticides is discussed.