Abstract: ObjectiveToxicity of four biopesticides against Pseudodendrothrips mori and their control effects in natu-ral environment were studied to provide reference for selection of pestcides against P. mori and development of safe mixed pestcides.MethodLeaf dipping method was usd to test indoor toxicity of four biopesticides( rotenon,veratrine,celan-gulins and spinetoramx)against P. mori. 1×,2×,4× recommended dosoge of each pesticide were prepared for field con-trol experiment during P. mori damage period. The survival number of P. mori was investigated in fixed trees 1,3,5 and 7 d before and after pesticides application. Correction control effect was calculated. Also,significant difference analysis for control effect of every pesticide was conducted by software SPSS 17.0.ResultThe toxicity of the four pesticides against P. mori was ranked as follows:60 g/L spinetoramx SC>7.5%rotenon EC>1%celangulins EC>0.5%veratrine SL. The field experiment showed that the control effects of three pesticides increased with the rise of dose concentration except for spinetoramx. The control effects of each dosoge of 60 g/L spinetoramx was 90.6%-99.8%1-5 d after applica-tion,which were higher than the other three pesticides. There was no significant differences between control effects 1-3 d after 1× recommended dosoge of 7.5%rotenon EC(30.0%-85.3%)and that of 60 g/L spinetoramx SC(90.6%-99.0%)(P>0.05,the same below). The control effect of rotenon was not available 5 d after application due to rainfall,indicating its poor persistence. Under 1× recommended dosage,the control effects of 1%celangulins EC and 0.5%veratrine SL was not good. The effects 1-5 d after application were 45.5%-57.2%and 23.3%-64.5%respectively,and there was no significant differences between them. Under 2 × recommended dosage,the control effects of 1%celangulins EC and 0.5%veratrine SL 1-5 d after application were 57.4%-65.8%and 57.0%-78.9%respectively,and the control effects were close.Conclu-sion60 g/L spinetoramx SC(1500 ×)is the first-choice pesticide for controling P. mori,7.5%rotenon EC is the second choice. During rainy season,750 times liquid of 7.5 rotenon EC,600 times liquid of 1%celangulins EC and 400 times liquid of veratrine SL can achieve sound control effects.