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Division of Agricultural Chemicals, Indian Agricultural Research Institute, New Delhi, 110 012, India
Studies have been conducted to stabilize azadirachtin - A with neem oil, neem meliacins1 and some known stabilizers. Neem oil and butylated hydroxy anisole (BHA) gave maximum stability to aza-A. When methanolic solution of aza-A and neem oil (1:1), and aza-A and BHA (9:1) were exposed to sun light, T1/2 was found to be 5.68 and 3.67 respectively while that of aza-A alone was 1.76 only. Further, the antifeedant activity of aza-A against tobacco armyworm, Spodoptera litura Fab was considerably enhanced following incorporation of BHA and neem oil. Fifty two and 27% antifeedancy were observed with aza-A mixed with neem oil and BHA respectively as compared to 10% antifeedancy observed with aza-A alone. The apparent enhancement in antifeedant activity was attributed to the possible stabilizing effect of neem oil and BHA2
