DEVELOPMENT OF 0.5% AZADIRACHTIN MICROENCAPSULE AND TEST FOR ITS ACTIVITY

0.5% azadirachtin microencapsules (Azadirachtin MC) manufactured with the method of common solid phase grinding are made from β-CD and azadirachtin. In a laboratory assay, the LC_(50) of Azadirachtin MC against the 4~(th) instar larvae of Pieris rapae were determined to be 4.3202±0.3180 mg/L and its CL_(0.95) 3.7389～4.9913 mg/L. P. rapae apparently refused to eat the food treated with Azadirachtin MC at 5～260 mg/L with an anti-feeding rate of 85.60%~82.44% and an anti-feeding index of 11.82~14.94. Field spray with Azadirachtin MC solution at 10, 6.25 and 4.55 mg/L gave a corrected control efficiency of (85.89%), 82.95% and 78.97%, respectively, as determined 3 days after the treatment and 81.86% 82.48% and 80.88% as determined 7 days after the treatment. In contrast, the control efficiency of Azadirachtin EC was 77.31% and that of Pardon was (84.38%). ANOVA showed that no significant difference was present among them at P=0.05.