Abstract
Activities of 5 chitin synthesis inhibitors against Thrips palmi infesting musk melons were eveluated in the laboratory and some compounds were applied on musk melons grown in a greenhouse from 1987 to 1988, in Shizuoka Prefecture, Japan. Five compounds of diflubenzuron (DFB, 235 ppm), teflubenzuron (TFB, 50 ppm), chlorfluazuron (CFA, 50 ppm), flufenoxuron (FFX, 50 ppm) and chiromazine (CHM, 750 ppm) were utilized. The former 4 compounds belong to benzoylphenyl ureas. After foliar spraying with the 5 compounds, it was observed that the numbers of mature larvae whcih dropped from leaves in order to pupate decreased drastically. Nolarvae treated with these chemicals pupated, except for those treated with CHM. The same larvicidal activity was observed after dipping treatments of mature larvae treated with DFB, TFB, CFA and FFX. DFB, CFA and FFX also showed ovicidal activity in adults LC50 values of FCA and DFB for mature larvae were 13 ppm and 140 ppm respectively. In foliar application of CFA, FFX and DFB on musk melons grown in a greenhouse, CFA and FFX controlled the thrips much better than DFB and conventional spraying of methidathion and BPMC.
