Abstract:

Toxicities of matrine, avermectin and Bacillus thuringiensis (Bt) against Corythucha ciliata were evaluated in laboratory by leaf-dip method. The results showed that matrine had the highest toxicity among the three reagents, and the LC₅₀ to lst nymph, 5th nymph and adults of C. ciliata were 0.195 7, 194.9 and 197.3 mg·L^–1, respectively. The LC₅₀ of avermectin for three ages’ insects were 10.66, 420.5 and 472.0 mg·L^–1, and that of BT were 3.23,1 414.2 and 6 967.2 mg·L^–1. The influence of three pesticides on detoxification enzymes was also detected and the results indicated the activities of carboxylesterase (CarE), acetylcholinesterase (AChE) and glutathione-s-transferase (GST) in the BT-treated insects were significantly higher than those in the control. The GST activity of three development stages, the CarE activity of adult and the AchE activity of lst nymph with avermectin treatment were significantly higher than the control. The GST activity of three development stages and the AchE activity of lst nymph treated with matrine were significantly higher than the control. The activities of CarE, AChE and GST were different among development stages of C. ciliata.

Key words: Corythucha ciliata, biological pesticide, toxicity determination, carboxylesterase, acetylcholinesterase, glutathione-s-transferase