Indoor toxicity of azadirachtin to Spodoptera frugiperda and its control effect in field.

Abstract

Objective: To evaluate the toxicity and control effect of azadirachtin to Spodoptera frugiperda and provide a technical reference for prevention and control of Spodoptera frugiperda. Method: The toxicity and field control effect of azadirachtin on Spodoptera frugiperda were determined by soaking leaf method and spraying method. Result: Under indoor condition, the LC₅₀ values of 2^nd and 3^rd instar larvae were 0.59 and 0.46 mg/L respectively, when treated with 0.3% azadirachtin EC after seven days; At seven days after treated with 40% azadirachtin dry powder, the LC₅₀ values of 2^nd and 3^rd instar larvae were 0.93 and 0.79 mg/L respectively; At three days after treated with 0.3% azadirachtin EC, the AFC₅₀ values of 2^nd and 3^rd instar larvae were 0.30 and 0.12 mg/L respectively; At three days after treated with 40% azadirachtin dry powder, the AFC₅₀ values of 2^nd and 3^rd instar larvae were 0.53 and 0.30 mg/L respectively. When 0.3% azadirachtin EC was diluted 500 times and sprayed on corn, the control effects on S. frugiperda reached 24.83%, 50.34% and 75.50% after 1, 3 and 7 days respectively. Conclusion: Azadirachtin has good toxicity and antifeedant activity, and the control effect on S. frugiperda is better at seven days after treatment. Azadirachtin has a broad application prospect in controlling S. frugiperda.