INSECT GROWTH REGULATORS: PROMISING EFFECTS ON CITRUS THRIPS (THYSANOPTERA: THRIPIDAE)

Several insect growth regulators (IGRs) were tested against citrus thrips, Scirtothrips citri (Moulton), in Munger cells. In all larval tests, the IGRs worked by preventing the thrips from developing to the pupal or adult stages. After exposing adult females to IGR residues, numbers of emerging progeny were reduced, although these results did not always rank the IGRs in the same order as the larval tests. The most effective IGR tested was UC84572, followed by cyromazine. Avermectin B1, a streptomycete-derived lactone, did not show IGR activity but acted as an insecticide and controlled the thrips at a much lower percentage active ingredient.