Activities of 6 Kinds of Insecticides Aginst the Larvae of Plutella xylostella

The toxicities of Chlorfenapyr, Chlorine insects benzamide, Emma streptozotocin, Diafenthiuron, Abamectin and Fipronil to 3 instar larvae of Plutella xylostella were tested by leaf-dipping method. The results indicated that Emma streptozotocin activity was the highest after 24 h with the LC50 of 22.21 mg/L. Diafenthiuron activity was the lowest with the LC50 of 996.17 mg/L. The most toxic insecticides were Emma streptozotocin and Chlorine insects benzamide after 48 h with the LC50 of 13.08 mg/L and 13.90 mg/L, the minimal toxicity insecticide was Diafenthiuron with the LC50 of 244.57 mg/L. The most toxic insecticides were Chlorine insects benzamide and Emma streptozotocin with the LC50 of 4.77 mg/L and 8.59 mg/L, the minimal toxicity insecticide was Diafenthiuron with the LC50 of 135.94 mg/L after 72 h.