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

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.