CHOLESTEROL OXIDASE - AN OOSTATIC AND LARVICIDAL AGENT ACTIVE AGAINSTTHE COTTON BOLL-WEEVIL, ANTHONOMUS-GRANDIS

The enzyme cholesterol oxidase (E.C.1.1.3.6), purified from Streptomyc es culture filtrate was previously found to have oral insecticidal act ivity on neonate larvae of the boil weevil (Anthonomus grandis grandis Boheman) from a laboratory population. In the present study, second i nstar larvae were also controlled by the enzyme at diet concentrations similar to those which control neonates (12 day LC(50) = 2.4 mu g.ml( -1) in diet). Larvae from field-collected adults were similarly suscep tible to cholesterol oxidase in the diet. When ingested by adult femal es during the mating/pre-oviposition period, cholesterol oxidase great ly reduced subsequent oviposition (83% reduction in eggs laid as compa red to controls) and larval survival (97% reduction from controls). Di ssection of treated adult females revealed poorly developed ovaries an d few developing oocytes. These studies were conducted to further eval uate the utility of cholesterol oxidase in a program to establish boil weevil-resistant transgenic cotton.