【作者】 王慧；

【导师】 林华峰；

【作者基本信息】 安徽农业大学 ， 植物保护， 2013， 硕士

【摘要】 烟粉虱Bemisiatabaci（Gennadius）是一种世界性重要害虫。长期以来，烟粉虱依赖于化学防治，抗药性问题十分突出。因此，研究开发经济有效防治烟粉虱的可持续替代技术迫在眉睫。本文对从本实验室的菌种资源库中选取的3株绿僵菌和6株球孢白僵菌菌株，分别进行了菌株营养生长量、产孢初始时间、产孢量、萌发性状等生物学特性的比较，并采用叶片浸渍法对烟粉虱3～4龄若虫开展毒力测定试验，利用时间-剂量-死亡率模型对实验数据进行模拟分析，揭示试虫死亡率随时间和孢子剂量变化的趋势，以期筛选出对烟粉虱若虫高致病力菌株；同时研究筛选出的高致病力菌株与常用化学农药的相容性及与相容性较好的化学农药混配后的杀虫效果，为开发生产防治烟粉虱的真菌制剂提供理论支持。主要获得以下结果：1、烟粉虱高致病力真菌菌株的筛选选择了3株绿僵菌和6株球孢白僵菌菌株分别进行了菌落营养生长量、产孢初始时间、产孢量和孢子萌发率的测定。结果表明：不同菌株之间生物学特性差异显著。3株绿僵菌菌株中，Mf62菌株培养10d的菌落直径最大、产孢初始时间相对较短、产孢量和24h的孢子萌发率最高，分别为6.97cm、130h、7.06×108孢子·cm-2和97%;6株球孢白僵菌菌株中Bb781、Bb84和Bb52的菌落营养生长量、产孢初始时间、产孢量和萌发率较好，最好的是Bb781菌株，分别为9.0cm、115h、10.17×108孢子·cm-2和99.9%。总体比较可见，球孢白僵菌菌株Bb781的生物学特性最好。3株绿僵菌菌株中，绿僵菌Mf62菌株的致病力最强，10d的累计死亡率达45.33%；而Mf21、Ma98菌株的致病力较差，累计死亡率仅为12.33%和36%，但3株绿僵菌的致死中时间都较长，达10d以上，因此3株绿僵菌菌株对烟粉虱若虫都不具备较好的防治效果。6株白僵菌菌株中，Bb781菌株的致病力较强，致死中时间较短，仅5.75d，且10d累计死亡率达83.67%，Bb84菌株次之，致死中时和累积死亡率分别为6.91d和77%。Bb22菌株最差，累计死亡率仅达30%。研究表明，不同菌株对烟粉虱若虫的致病力差异显著，球孢白僵菌菌株Bb781和Bb84对烟粉虱若虫均有较高致病力。在筛选出Bb781和Bb84菌株的基础上，测定了两种菌株从低到高5种浓度梯度的孢子悬液对烟粉虱若虫的致病力。结果表明：随着孢子浓度的增加，烟粉虱若虫的累计校正死亡率逐渐增加。经Bb781处理的烟粉虱若虫的死亡率在各个浓度水平上都高于Bb84，两组处理的最高死亡率分别为91.11%和85.56%。虽然接种两种菌株烟粉虱若虫的累积死亡率差异不显著，但接种Bb781菌株1×108孢子悬液第三天烟粉虱若虫的累计死亡率就已达到接种Bb84菌株1×108孢子悬液的3倍，Bb781菌株的致死速度快于Bb84，这对解决真菌制剂本身所具有的防效滞后性有很大的帮助，因此选择球孢白僵菌Bb781菌株做进一步分析。利用时间-剂量-死亡率模型对实验数据进行模拟分析，所建模型均顺利通过Hosmer-Lemeshow拟合异质性检验，表明模型拟合良好，并由模型估计出了球孢白僵菌Bb781菌株对烟粉虱若虫的致死剂量与致死时间。接种后第7d，LC50值为1.60×105个孢子·mm-2,LC90为3.59×107个孢子·mm-2。球孢白僵菌Bb781孢子悬液对烟粉虱若虫的致死时间与对数剂量相关，供试菌剂LT50值随着对数剂量的增加而递减，对数剂量由6.0增加到8.0时，LT50由4.3d降为2.9d。可见球孢白僵菌Bb781菌株对烟粉虱若虫具有较强的毒力，在烟粉虱生物防治中具有广阔的应用前景。2、常用化学农药对球孢白僵菌Bb781菌株的影响以对球孢白僵菌Bb781菌株营养生长量、产孢量和孢子萌发率的抑制率为评价指标，测定6种常用化学农药在致死浓度、亚致死浓度、次亚致死浓度下与球孢白僵菌Bb781菌株的相容性。结果表明：随着化学农药浓度的不断增高，对菌株的抑制率也不断上升。阿维菌素对孢子的抑制作用最强，在次亚致死浓度时菌株营养生长量、萌发率和产孢量的抑制率分别为71%、71.88%和67.92%；吡虫啉、啶虫脒和虫螨腈与球孢白僵菌Bb781孢子的相容性较好，抑制作用最弱的是吡虫啉，在次亚致死浓度时菌株生长量的抑制率为7.04%，产孢量的抑制率也仅为8.18%，萌发率的抑制率则只有1.74%，与孢子相容性最好。3、球孢白僵菌Bb781菌株与化学农药混配对烟粉虱若虫的毒力本实验研究了球孢白僵菌Bb781菌株孢子悬液与低浓度相容性较好的化学农药混配对烟粉虱若虫的毒力。结果表明：单独使用球孢白僵菌Bb781菌株孢子悬液，第7d的累计死亡率为76.67%，吡虫啉、啶虫脒和虫螨腈与球孢白僵菌Bb781菌株孢子悬液混用后，第7d的累计死亡率分别达到91.11%、87.78%、84.44%。可见，菌药混合物比单独施用球孢白僵菌Bb781菌株孢子悬液明显提高了毒力，而且缩短了潜伏期，第2d累计死亡率就明显开始上升。三种混剂的LT50均小于球孢白僵菌Bb781菌株孢子悬液，尤其吡虫啉的混剂，LT50仅为2.9d。因此，球孢白僵菌Bb781菌株孢子悬液和吡虫啉混合施用时对烟粉虱若虫毒杀效果最好。更多还原

【Abstract】 Bemisia tabaci is an important worldwide pests. For a long time, Bemisia tabaci dependent on the chemical control, and the drug resistance is very prominent.Therefore, the research and development on effective and economic sustainable alternative technology against Bemisia tabaciis imminent.In this paper,3strains Metarhizium anisopliae and6strains of Beauveria bassiana were selected from the laboratory strain repository, and had conducted a series of comparative experiments like the vegetative growth of the strains, the initial time of sporulation, spore production rate and germination properties in terms of biological characteristics.And conducting virulence determination tests on whiteflies3-4instar nymphy by leaf dipping, using time-dose-mortality model for simulating the experimental data analysis, reveal the test insect mortality rat e and spore dose trends over time, in order to screen out the high virulent strains against Bemisia tabaci larvae. In the meantime, carrying out researchs about the compatibility between the highly pathogenic strains and commonly-used chemical pesticides and its insecticidal effect with the chemical pesticides which mixed with the highly pathogenic strains, it provides theoretical support for developing production of fungal agent for control of Bemisia tabaci. The main results are as follows:1. Screening the high virulence fungi strains of Bemisia tabaciSelect three strains of Metarhizium anisopliae and six strains of Beauveria bassiana and determinate their biological characteristics of vegetative growth, time of sporulation initial, sporulation and spore germination rate.The results showed:the biological characteristics is significant different between the different strains. In three strains of Metarhizium anisopliae,the Mf62strain has the largest colony diameter trained ten days, the sporulation initial relatively short period of time, sporulation and spore germination rate in24h, they are6.97cm,130h,7.06×108spores·cm-2and97%; In six strains of Beauveria bassiana, Bb781, Bb84and Bb52colonies vegetative growth, the initial time of sporulation, sporulation and germination rate are better, the best is Bb781strains, they are9.0cm,115h,10.17×108spores·cm-2and99.9%.Overall visible,the biological characteristics of Beauveria bassiana Bb781strain is best.In three strains of Metarhizium anisopliae, the strongest pathogenicity is Mf62strain, ten days cumulative mortality is45.33%; While Mf21and Ma98strain pathogenicity are poorer, cumulative mortality rate are only12.33%and12.33%, but the death time of three strains of Beauveria bassiana is longer more than10d, so three strains of B. bassiana strains to Bemisia tabaci larvae don’t have good control effect. In six strains of Beauveria bassiana strains, the strongest pathogenicity is Bb781strains, the half death time is shorter, only5.75d, and the ten days cumulative mortality was83.67%, and the Bb84strains is less than Bb781,the half death time and cumulative mortality rates were6.91d and77%. The worst strains is Bb22, only30%of the total mortality. Research shows that different strains have significant difference of Bemisia tabaci larvae in pathogenicity, Bb781and Bb84strains on Bemisia tabaci larvae were higher pathogenicity.On the basis of filtering out Bb781and Bb84strains,determined the virulence of two strains from low to high concentration gradient spore suspension on Bemisia tabaci larvae. The results showed:the cumulative corrected mortality of Bemisia tabaci larvae gradually increased with the increase of the concentration of spores. The mortality rates of Bemisia tabaci larvae processed by Bb781on various levels are higher than Bb84, two groups deal with the highest mortality rates were91.11%and85.56%, respectively. Inoculated with two strains of cumulative mortality of nymphs difference was not significant, but inoculation with Bb781strains1×108spore suspension on the third day the accumulated mortality rates of Bemisia tabaci larvae vaccination Bb84strain had reached3times than Bb84strains1×108spore suspension,the lethal speed of Bb781strains is faster than Bb84, which lag a great help to solve the efficiency of anti-fungal agents, so select Beauveria bassiana Bb781strains for further analysis.Using the time-dose-mortality model simulation analysis, the model passed the Hosmer-Lemeshow fit test for heterogeneity, indicating a good model,and estimated the lethal dose and lethal time of Beauveria bassiana strain Bb781on Bemisia tabaci larvae by the model.After the seven inoculation day, the LT50value of1.60×105spores·mm-2, LT90value of3.59×107spores·mm-2. Beauveria bassiana the Bb781spore suspension on Bemisia tabaci larvae lethal time with the number of dose related for the test agents LT50values decrease with the increase in the number of doses of the number of doses from6.0to8.0, the LT50reduced by the4.3d to2.9d. Visible the Beauveria bassiana Bb781strains with a strong virulence on Bemisia tabaci larvae,in the biological control of Bemisia tabaci has broad application prospects.2.The the compatibility of Beauveria bassiana Bb781strains with the commonly used chemical pesticides For ball spore Bb781strains of beauveria bassiana in nutrition growth, spore production rate and spore germination inhibitory rate of evaluation indexes, determinate six kinds of commonly used chemical pesticides in the lethal concentration, concentration of sub lethal concentration, time and death under the compatibility with the ball spore Bb781beauveria bassiana strains. Results show that with the increasing of concentration of chemical pesticide, the inhibition rate of strain is also rising. Abamectin strongest inhibition of spore strains during times of sub lethal concentration nutrition growth, germination rate and spore production quantity the inhibition rate of71%,71.88%and67.92%respectively; Imidacloprid, organism amidine and insect mite acrylic with ball spore Bb781Beauveria bassiana spores has good compatibility, the inhibition is the weakest of imidacloprid, in times of sub lethal concentration when the strain growth inhibitory rate was7.04%, the amount of spore production of inhibition rate is only8.18%, germination rate, the inhibition rate of only1.74%, the best compatibility with spores.3.Toxicity of Beauveria bassiana strain Bb781mixed with chemical insecticides on Bemisia tabaci larvaeThis study the virulence of Beauveria bassiana strain Bb781spore suspension mixed with the low concentrations of chemical pesticides with better compatibility on Bemisia tabaci larvae. The results showed that:used alone Beauveria bassiana strain Bb781spore suspension seven days cumulative mortality rate was76.67%,Beauveria bassiana strain Bb781spore suspension mix with imidacloprid, acetamiprid and Chlorfenapyr, seven days cumulative mortality rate reached91.11%,87.78%,84.44%, respectively. Visible bacterial agents mixture than single application of Beauveria bassiana strain Bb781spore suspension significantly increased virulence, but also shortens the incubation period,2d cumulative mortality rate began to rise significantly. Three mixtures LT50less than Beauveria bassiana strain Bb781spore suspension, especially imidacloprid mixture, the LT50of only2.9d. Therefore, the application of Beauveria bassiana strain Bb781spore suspension mixed with imidacloprid poisoning on Bemisia tabaci larvae is the best.更多还原