Control Effects Of Different Insecticides On Bemisia Tabaci(Gennadius) And Application Technology Study Of Abamectin

?Bemisia tabaci(Gennadius) is one of the most important pests of greenhouse vegetables. Control effects of several insecticides on B. tabaci were studied. Action mode of abamectin, as well as its application techniques in field in B. tabaci were investigated in this paper. The major results are as follows:1. Biological activities of several insecticides on B. tabaci were studied. The results of biological activities indicated that the toxicity of abamectin was the highest (LC50: 2.286 mg/L) to adult B. tabaci, followed by Beta-cypermethrin,azadirachtin,imidacloprid,pymertrozine (15.07mg/L,22.88mg/L,30.64mg/L,51.10mg/L, respectively). Imidacloprid was most toxin (LC50: 169.50mg/L mg/L) to eggs of B. tabaci, while abamectin had the highest toxicity to both low and high instar nymph (LC50: 1.25mg/L,2.25 mg/L, respectively). The LC50 of Beta-cypermethrin,imidacloprid,pymertrozine,azadirachtin to low instar nymph were 15.46mg/L,23.48mg/L,45.88 mg/L,46.79mg/L, respectively, while the values to high instar nymph were 33.5mg/L,34.99mg/L,51.76mg/L,54.52mg/L, respectively. The LC50 of Buprofezin,chlorpyrifos,Chlorantraniliprole to both low and high instar nymph of B. tabaci were more than 94.90 mg/L.2. The results of field experiments showed that control efficacy of 1.8% abamectin EC,25% pymertrozineWP,0.3% azadirachtinEC after 9 days treatment with 2000x were the highest, with the value being more than 80.72%, followed by 10% imidacloprid WP, with the value being 80.00%, and 40% chlorpyrifosEC,25% Buprofezin WP,4.5% Beta-cypermethrin EC,20% Chlorantraniliprole SC had the lowest efficacy, with the value being less than 66.62% after 9 days treatment with 1000x.3. Different action modes of abamectin were tested. The results showed that abamectin had several kinds of action mode, including stomach poison toxicity,contact toxicity and intake transportation activity. The efficacy order of different action modes was intake transportation activity is stomach poison toxicity > contact toxicity. The effects of abamectin on activity of several enzymes in B.tabaci were tested. The results indicated that there was reversible inhibition of abamectin with LC50 concentration on activity of carboxylesterases and glutathione s-transferase agents in B. tabaci. At 12h after abamectin treatment the specific activity of carboxylesterases and glutathione s-transferase agents were 0.6814 and 0.8677, respectively which increased with the time, and it reached 1.1929 times and 1.1985 times at 48h after abamectin treatment, respectively.4. There were significant influences of environmental temperature on application effect of abamectin. The results showed that the toxicity of abamectin at 32℃was 14.20 times higher than that at 19℃. The corrected mortality of abamectin to adult B. tabaci was 80.55% within 15 days after treatment, which decreased with the time.