【摘要】 通过对不同化学防治水平苹果园叶螨种群数量的调查、室内杀虫(螨)剂对叶螨相对毒性的测定以及对叶螨在苹果叶片上的分布及为害性状的考察表明:①频繁施用杀虫(螨)剂的果园.苹果全爪螨的种群数量明显大于李始叶螨种群数量;施用杀虫(螨)剂次数少的果园,李始叶螨的相对数量均高于苹果全爪螨;多年不喷洒杀虫(螨)剂的果园.李始叶螨种群数量占绝对的代势.②苹果全爪螨对三氯杀螨醇的扰性显著强于李始叶螨.③李始叶螨和苹果全爪螨在苹果叶片上存在着相互干扰.营养竞争等现象.进而证实田间大量使用三氯杀螨醇是促使兰州苹果园叶螨优势种演变的主要原因.并对压低苹果全爪螨发生基数和控制苹果园叶螨的防治对策进行探讨.更多还原

【Abstract】 Population densities of spider mites Eotetramn(?)chus pruni and Panonychuusulmi were compared in 10 apple orchards of varying chemical treatment levelsin Lanchou,Gansu Province in 1987.Resistance of the two spider mitesagainst 4 miticides,Kelthane、DVP、Phoxim and optunal were tested in theIaboratory.The resultes demonstrated that P.u(?)i had a higher population thanE.pruni in orchards where frequent miticide application was made,while E,prunihigher in orchards where less intensive chemical treatment was carried out..pruni occupied a dominant status in abandoned orchards where no chemicalEspraying was received.The resistance test rev aled that P.ulmi had moreh stronger resistance against kelthane than E.pruni.Therefore,the boom of P.ulmiwas the consequence of selection of pesticides.The interspecific disturbanceand the competition for nutrition of the two spider mites were examined throughlaboratory and field observation.A tentative IPM program in Lanzhou appleorchards was proposed,and the prospect of the utilization of the phytos(?)iidmite T phlodrmus occidentalis in controlling spider mites on apple trees was dis-cussed as well.更多还原