Toxicity of Plants Crude Extract on Common Cutworm (Spodoptera litura Fabricius)

Abstract

     The toxicity of plants crude extracts from neem (Azadirachta indica), turmeric (Curcuma longa) and Siam weed (Chromolaena odorata) in controlling cotton leafworm, Spodoptera litura, was conducted in the laboratory. Each crude extract (1, 3, 5 and 10% w/v) was tested for contact and oral toxicity. In term of contact toxicity, the results indicated that the 10% turmeric crude extract was the highest effective to cause Spodoptera litura die 83.33% in 7 days, followed by 10% Siam weed crude extract for 63.33% and 1% neem crude extract was lowest effective (6.67%) . The LC₅₀ values at 7 days of turmeric, Siam weed and neem were 5.66, 6.92 and 24.55, respectively. According to oral toxicity, 10% Siam weed extract caused Spodoptera litura die 43.33% highest than that of all crude extracts. The LC₅₀ values of oral toxicity at 7 days of Siam weed, neem and turmeric were 10.47, 14.57 and 14.78, respectively. In summary, 10% crude extract of turmeric and Siam weed have high ability of controlling Spodoptera litura within 7 days and could be used in planning insect pests control, reducing and replacing chemical use in control method.