| Trichogramma spp. has been the most studied pests biological control method and the most widely used type of important insect pest at home and abroad as the egg parasitoid wasps. In order to coordinate the relationship of biological control and chemical control, this study determined the toxicity of different types of commonly used pesticide to adult and pupae of natural enemy Trichogramma ostriniae, screening for low and high toxic pesticides to T. ostriniae and testing the typical pesticides on lasting toxic action to it and comparing the influences on the other target Encarsia formosa. The main research results are as follows:1. The results of different type of pesticides acute toxicity to adult T. ostriniae showed that the LR50of chlorpyrifos, carbosulfan, phoxim, thiamethoxam, Dinotefuran and dichlorvos were from1.97×10-6to2.27×10-4mg·cm-2. The safety factor of them were less than0.04, belonging to the highest toxicity pesticides. The safety factor of imidacloprid, lambda-cyhalothrin and abamectin were less than0.2, belonging to high toxicity pesticides. Chlorantraniliprole, pyridaben and pymetrozine were safe to T. ostriniae. In fungicides, the LR50of azoxystrobin and difenoconazole were1.30×10-4and2.35×10-4mg·cm-2, belonging to high toxicity. Propiconazole and tebuconazole were medium risk to it. Herbicides nicosulfuron, paraquat and2,4-D butyl ester were high toxicity pesticides to T. ostriniae. Pendimethalin, acetochlor and atrazine were medium toxicity pesticides to T. ostriniae. The other herbicides were safe to it.2. The results of different type of pesticides toxicity to pupae of T. ostriniae showed that the insecticides phoxim, chorpyriphos and dichlorvos were high toxicity to pupae of T. ostriniae using the recommended doses. Eclosion rate of them were14.79%-19.34%,and that is significant different compared with the control46.07%. Imidacloprid, dinotefuran, thiamethoxam, lambda-cyhalothrin, abamectin and carbosulfan also had toxicity to T. ostriniae pupae. Chlorantraniliprole, pyridaben and pymetrozine were safe to pupae of T. ostriniae. Selected fungicides had no significant difference compared with control, and they were safe to pupae of T. ostriniae. In herbicides, mesotrione, pendimethalin and acetochlor were safe to pupae of T. ostriniae. The other herbicides had high toxicity to it.3. The toxicity of pesticide ready-mixture to T. ostriniae showed that abamectin-thiamethoxam, abamectin-imidacloprid and Abamectin-chlorfenapyr were highest toxicity pesticides. Abamectin-pymetrozine and Abamectin-pyridaben were safe to T. ostriniae. In6fungicide ready-mixtures, only azoxystrobin-chlorothalonil and azoxystrobin-hexaconazole were harm to T. ostriniae with LR501.85×10-3and8.96×10-4mg·cm-2. Azoxystrobin-dimethomorph and azoxystrobin-difenoconazole showed low eclosion rate to T. ostriniae.4. The results of8high-risk pesticides last Toxic-tests showed that the effect duration of thiamethoxam and abamectin to T. ostriniae were the longest among the selected pesticides. The mortality rate of them were64.15%and35.07%, respectively. They were significant difference compared with the control20.03%. After using carbosulfan, amistar, phoxim, dursban, lambda-cyhalothrin and imidacloprid7days, the mortality rate of T. ostriniae were not significant difference compared with the control.5. The results of the influence of6less toxicity risk pesticides to lifetime and parasitism rate showed that the pesticides can do some bad influence on the lifetime and parasitism of T. ostriniae. After the treatment of pendimethalin and acetochlor, the parasitism rate of T. ostriniae were29.98%and33.64%, respectively. It was significant lower compared with control57.36%. After the treatment of tebuconazole, pymetrozine, chlorantraniliprole and pendimethalin, the parasitism rate of T. ostriniae were37.32%,36.46%,42.97%and45.12%, showing no difference with control. Only mesotrione and pendimethalin had no effect on the lifetime of T. ostriniae. The lifetime after the treatmengt of pymetrozine, tebuconazole, acetochlor and chlorantraniliprole were1.90d,1.89d,2.25d and2.40d, they were significant different compared with control.6. The results of measurements of enzymatic activity showed that after the recommended dose treatment of pymetrozine, chlorantraniliprole and acetochlor, the GSTs active of T. ostriniae reduced obviously. It was significant different compared with control. The other pesticides had no effect to the GSTs active of T. ostriniae. Pymetrozine,chlorantraniliprole and tebuconazole had significant impact on the CarE active of T. ostriniae. It was significant different compared with control. the PO active of T. ostriniae enhanced obviously after the treatment of pymetrozine and chlorantraniliprole. The other pesticides had no effect on the PO active of T. ostriniae. Enzymatic determination reflected the chronic toxicity of pesticides to T. ostriniae. It can be reference frame of pesticides safety evaluation to T. ostriniae.1. The toxicity comparison of T. ostriniae and E. formosa showed that chlorantraniliprole,2,4-D butyl ester, imidacloprid, paraquat, difenoconazole, chlorpyrifos, thiamethoxam and acetochlor had higher toxicity T. ostriniae to than E. Formosa. And the toxicity of carbosulfan, abamectin, dinotefuran, pymetrozine, phoxim, lambda-cyhalothrin, pendimethalin and pyridaben were higher to E. formosa than T. ostriniae. Therefore, the selectivity of different parasitic wasp were different to pesticides. |
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