Bio-efficacy of some insecticides against cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae)

Laboratory bioassay of eight insecticides namely Chlorpyriphos 20 EC, Ethiprole+ imidacloprid 80 WG, Pymetrozine 50 WP, Lamda cyhalothrin 4.9 CS, Imidacloprid 30.5 SC, Acephate 95 SG, Thiacloprid 240 SC and Fipronil 5 SC was done against cotton mealybug, Phenacoccus solenopsis Tinsley. Among insecticides, Lamda cyhalothrin 4.9 CS was the most toxic with the lowest LD50 16.03 ppm followed by Chlorpyriphos 20 EC (LD50 27.56 ppm), Ethiprole+ imidacloprid 80 WG (LD50 44.82 ppm), Imidacloprid 30.5 SC (LD50 80.68 ppm), Thiacloprid 240 SC (LD50 87.13 ppm), Pymetrozine 50 WP (LD50 181.45 ppm), Acephate 95 SG (LD50 359.61 ppm), Fipronil 5 SC (LD50 705.59 ppm).