Study On Sublethal Effects Of Abamectin And Pyridaben To Neoseiulus Barkeri(hughes)

Neoseiulus barkeri is one of important biological control product to prevention and control of farmland orchard spider mites at present in China. After its release in the field will be inevitably affected by poison and sublethal effects of pesticide.In order to define the pestcides’ sublethal effects to predator mites, coordinating biological control and chemical control in the field, Abamectin and Pyridaben which are often used in the field prevention and control of spider mites were selected to test the impact of two pesticides’ sublethal concentrations(LC10、LC20、LC30) to Growth, feeding and the detoxification enzymes in N.barkeri, which aimed to supply the basic reference for the combination releasing N. barkeriand with chemical pesticides. The main results were as follows:1. By using the leaf spray method, the determination of virulence regression equation of Abamectin to Neoseiulus barkeri was y = 2.3105 + 3.4237 x, of which its LC10, LC20, LC30 concentrations were 2.0261 mg/L, 3.0924 mg/L, 3.9721 mg/L respectively. Virulence regression equation of Pyridaben to Neoseiulus barkeri was y = 2.2443 + 1.3895 x, its LC10, LC20, LC30 concentrations were 11.5054 mg/L, 23.8508 mg/L, 40.3454 mg/L.2. By building fertility life table, the two pesticides’ impact of LC10 and LC20 concentration to F0 and F1 group generation reproduction in N.barkeri were studied separately. The results showed that the longevity of female adult mites was 16.550 d of control group,and 15.667 eggs per female laying, F1 generation development period was 6.053 d, and F1 generation Intrinsic growth raterm = 0.136; after treated by abamectin LC10 and LC20 concentration of Abamectin, F0 generation’s longevity and each female laying number were significantly shorten, of which the female adult life(12.117 d) treated by LC20 reached the lowest, and per female laying number(9.183) was also the lowest. The maximum developmental duration was 6.454 d and the intrinsic strength was the lowest(rm = 0.127) of the F1 generation; After treated by Pyridaben LC10 and LC20 concentration, longevity and per female laying number in F0 generation significantly decreased, but the impact is inferior to Abamectin, and the impact on F1 generation is weak, developmental duration slightly prolonged and rm decreased slightly as well.3. Neoseiulus barkeri adult female mites had been treated respectively by Abamectin and Pyridaben sublethal concentration, then fitting the Disc equation of predatory functional responses to indicate the effects of two pesticide to Neoseiulus barkeri’s predation capacity.The results showed that daily feeding amount of N.barkeri decreased significantly treated by Abamectin sublethal concentrations(LC10, LC20, LC30). of which LC30 concentration had the greatest influence, the instantaneous attack rate reduced from 0.8285 to 0.5771, the biggest daily feeding amount reduced from 16.8014 to 13.8629; Pyridaben sublethal concentrations of feeding amount lower than that of abamectin treatment group obviously, concentration of LC30 instantaneous attack rate is 0.6881, the maximum daily feeding amount was 15.3095.4. The glutathione S- transferase(GST), multi-function oxidase(MFO) and carboxylesterase(Car E) specific activity, michaelis constant Km, the maximum reaction rate Vmax of Neoseiulus barkeri were analyzed by the effects of Abamectin and Pyridaben sublethal concentration to N.barkeri’s detoxification enzymes in the body.The results showed that Abamectin had the significant induction to GSTs and stimulated the specific activity of GSTs and Vmax rosed significantly, and with the rising of concentration, the action showed more stronger. And for MFOs and Car Es, the influence varies in different concentration, low concentration(LC10) induced MFOs and the activity of Car Es, and high concentration(LC20 and LC30) inhibit enzyme activity, little influence on activity of Car Es. Pyridaben also had the significant induction to GSTs, when the specific activity of GSTs rosed, it showed siginicant inhibiting effect to MFOs, and when the specific activity of GSTs reduced, the Vmax increased significantly, and high concentration showed obvious stumilation while low concentration showed not obvious.