Comparative Effects of Different Insecticides on the Spodoptera frugiperda under Laboratory Conditions

The fall armyworm, Spodoptera frugiperda, is a highly destructive phytophagous of agricultural crops in various countries around the world. The study focused on evaluating the toxicity of six insecticides namely, emamectin benzoate, chlorfenapyr, indoxacarb, methomyl, azadirachtin and KZ oil against the 2nd , 3rd and 4th larvals of S. frugiperda under laboratory conditions using the Leaf-dip method. The results exhibited that the fourth instar larvae of S. frugiperda was less susceptible to the examined insecticides than the larvae in their second and third instars. Moreover, the treatment of Emamectin benzoate showed a higher residual mortality effect against second, third and fourth instars of S. frugiperda larvae with an average of 68.67% compared to other tested compounds. While mineral oil treatment showed a lower effect on the residual mortality by 52.67%. The insecticides that were tested could be sorted as follows in descending order: emamectin benzoate, chlorfenapyr, indoxacarb, methomyl, azadirachtin and KZ oil. The corresponding LC50 values after 24 h. were 0.02, 0.07, 0.11, 0.14, 0.23 and 0.25 ppm for 2nd instar larvae , while in case of 3rd instar larvae were 0.04, 0.10, 0.21, 0.23, 0.28 and 0.29 ppm. On the other hand, the result could be descendingly arranged as follows: emamectin benzoate, chlorfenapyr, indoxacarb, methomyl, KZ oil and azadirachtin and corresponding LC50 values after 24 h. were 0.05, 0.12, 0.25, 0.34, 0.35 and 0.35 ppm for 4th instar larvae. According to the results, emamectin benzoate is a good component of an integrated pest management program.