【作者】 张发成；

【导师】 刘树生；

【作者基本信息】 浙江大学 ， 农业昆虫与害虫防治， 2002， 硕士

【摘要】 在蚜虫生物防治研究中，球孢白僵菌对蚜虫的毒力及其应用近年来受到关注。已有的研究大多集中在测试球孢白僵菌对成蚜的毒力，而对若蚜的毒力则缺乏研究，也未在种群水平上定量评估球孢白僵菌的控制潜能。 本文针对这一现状，选择了内吸性化学杀虫剂吡虫啉和一个对蚜虫毒力较强的球孢白僵菌菌株BBSG8702，以桃蚜为毒杀对象，开展以下三步相互衔接的研究。首先测定球孢白僵菌对桃蚜若蚜发育、存活和其发育为成蚜后产仔量的影响，在理论上更深入地分析该菌对桃蚜种群的控制潜能；第二步测试吡虫啉对桃蚜的致死和亚致死效应，为设计吡虫啉与球孢白僵菌联合应用提供依据；第三步测试桃蚜种群在球孢白僵菌单独作用、吡虫啉与球孢白僵菌联合应用两种情况下数量增长及种群年龄结构变化。研究目的是想在种群水平上更深入地了解球孢白僵菌对蚜虫种群的控制潜能，提出增高该菌对蚜虫控制潜能的新途径，为研制新型球孢白僵菌杀蚜制剂提供参考依据。 第一步应用球孢白僵菌侵染若蚜的试验结果表明，用球孢白僵菌接种桃蚜1、4龄若蚜后，若蚜进入下一个龄期的脱皮时间均略有提前，接菌后12天内的感菌死亡率分别为7.2％和58.7％；感菌的4龄若蚜大部分是发育为成蚜后死亡，死亡高峰为接菌后第7～10天；接菌的4龄若蚜发育为成蚜后，感菌死亡成蚜的产仔量略有下降，而未感菌死亡成蚜的产仔量与对照成蚜的相比没有差异。1龄若蚜接菌后未感菌死亡的发育为成蚜后，其产仔量与对照成蚜相比没有差异。 第二步的吡虫啉浓度筛选试验表明，0.1μg/ml的吡虫啉明显延长桃蚜1龄若蚜的发育历期，发育为成蚜后的产仔量也明显下降；虽然2μg/ml和4μg/ml吡虫啉不能明显延长桃蚜4龄若蚜的发育历期，但其发育为成蚜后的产仔量显著降低。室内联合应用白僵菌和0.4μg/ml吡虫啉处理2龄若蚜时，其感菌死亡率明显提高；而联合应用0.5μg/ml浓度的吡虫啉和白僵菌处理3龄若蚜时，其感菌死亡率没有增加。 第三步种群水平的试验表明，单独应用球孢白僵菌时，以无翅成蚜开始的桃蚜种群，在接菌后第6天，不接菌对照和接菌处理之间只有成蚜数量差异显著，虽各龄期若蚜数量和桃蚜总数接菌处理与不接菌对照之间差异不显著，但接菌处理的总数量少于不接菌对照的总数量；但在接菌后第13天，接菌处理的种群数量已经增长 到与不接菌种群数量相当的水平；以4龄无翅若蚜开始的桃蚜种群，在接菌后第6 天接菌处理与不接茵对照之间的种群数量就很接近。室内以无翅成蚜开始的桃蚜种 群，接菌后第7天1龄若蚜和成蚜数量不接菌对照和接菌处理之间差异显著，第门 天只有4龄若蚜的数量在对照与处理之间有差异。不论是在田间还是在室内，接菌 10无以后桃蚜总数在不接菌对照和接菌处理之间的差异从未达到显著水平，这表明 球抱白僵菌单独并不能对桃蚜种群数量的增长起到控制作用。当白僵菌和微量毗虫 啦联合应用时，处理后第9天和 16天白僵菌十毗虫琳处理中的桃蚜总数低于对照。 白僵菌和毗虫晰三种处理各自的桃蚜总数，虽然在接菌后第23天的取样中，各处理 之间的差异未达到显著水平，但毗虫琳十白僵菌处理的数量比其它三种处理的要低， 这表明白僵菌和微量毗虫琳联合应用可在较长时间内对桃蚜种群数量增长起到控制 作用。 综合分析以上三步试验结果可见，球抱白僵菌由于其侵染速度较慢，不能有效 地侵染和致死若蚜，对成蚜的致死速度慢且对感菌个体在死亡前产仔量降低不明显， 故单独使用后对桃蚜种群增长速率只在短期内有轻微的降低，总体上未能起到明显 的控制作用。微量的毗虫咐可以显著延缓低龄若蚜的发育速率，给球泡白僵菌侵染 低龄若蚜并将其致死在成蚜之前创造机会。球抱白僵菌与微量毗虫咐联合应用可以 提高球泡白僵菌的侵染力，并可对桃蚜种群增长起到一定的控制作用。更多还原

【Abstract】 In the studies of biological control of aphids, the virulence ofBeauveria bassiana to aphids and its utilization have received considerable attention in recent years. However, most studies up to date have concentrated on the evaluation of virulence of B. bassiana to aphid adults, the virulence to the nymphal stages has been rarely studied, and the potential of B. bassiana as a biological control agent of aphids has not been examined quantitatively at the population level.In this study, we chose a systemic insecticide, imidacloprid, an isolate of B. bassiana highly virulent to aphids, BBSG8702, and the green peach aphid, Myzuspersicae, as the target pest, and conducted the research in the following three interconnected steps. First, the effect of B. bassiana on the nymphal development and survival and the subsequent fecundity of these inoculated nymphs after they had become adults was examined, in order to analyse the potential of the fungus as a control agent for populations of the green peach aphid; next, the lethal and sublethal effects of imidacloprid on the green peach aphid were tested, to provide the necessary data for the combined utilization of imidacloprid and B. bassiana; and finally, the population increase and the change of population structure were investigated when B. bassiana alone or B. bassiana combined with imibacloprid were applied. Our purpose was to further understand the potential of B. bassiana as a biological control agent of aphids at the population level, to find out new ways for enhancing the potential of the fungus, and to provide information for developing new aphicide formulations with B. bassiana.In the first part of the study, when first or fourth instar nymphs of the green peach aphid were inoculated with B. bassiana, the durations to the first moult following inoculation were slightly decreased, and the levels of cumulative mortality at the 12l day after inoculation reached 7.2% and 58.7% respectively. Deaths of the infected aphids inoculated with the fungus at the fourth instar occurred after they had become adults, and the peaks of mortality occurred at 7-10th day after inoculation. When the nymphs inoculated with the fungus at the fourth instar had developed to adults, the fecundity of the adults infected by the fungus was slightly decreased, while the fecundity of uninfected adults remained unaffected, compared to that of the adults in the control. When the nymphs inoculated with the fungus at the first instar had developed to adults, their fecundity did not differ from that of the aphids in the control.In the second part of the study, the test results showed that O.lu.g/ml imidacloprid significantly increased the development time of the first instar nymphs of aphid, and when these treated nymphs had developed to adults, their fecundity was significantly lower than that of the adults in the control. Although 2ug/ml and 4u.g/ml imidacloprid applied to nymphs at the fourth instar did not increase the development time of that instar, the fecundity of these treated aphids after they developed to adults was much lower than that of the adults in the control. When B. bassiana and 0.4(ig/ml imidacloprid were both applied to nymphs at the second instar, the mortality induced by the fungus was significantly increased. However, when B. bassiana and 0.5|ig/ml imidacloprid were bothapplied to nymphs at the third instar, the mortality induced by the fungus did not increase.In the third part of the study with experimental populations of the green peach aphid, when the cohorts were started with apterous adults and B. bassiana was applied alone, at the sixth day after inoculation the number of adults in the treatment with the fungus was significantly lower than that in the control. Although the numbers of individual instars did not differ significantly between the control and the treatment, the total number of aphids in the treatment with the fungus was lower than that of the control. However, at the 13th day after inoculation, the total number of aphids in the treatment ha更多还原