球孢白僵菌与印楝素对温室白粉虱实验种群影响研究

发布时间：2018-06-28 06:26

本文选题：温室白粉虱 + 球孢白僵菌　；参考：《西南大学》2017年硕士论文

【摘要】：温室白粉虱(Trialeurodes vaporariorum Westwood)是一种世界性农业害虫,具有分布广、寄主多的特点,目前生产上主要依靠使用化学农药控制其发生与危害。由于化学药剂的大量使用,以及温室白粉虱发育期短、繁殖力强的生态对策,导致其抗药性急剧上升。应用生物防治手段不但可以延缓害虫抗性增长,还具有环境友好、持续控制等优势,合理开发使用生防技术越来受到关注。因此,本研究开展生防真菌球孢白僵菌(Beauveria bassiana)和印楝素对温室白粉虱的致病力测定,评价两者混配对其发育、繁殖与存活的影响,并利用扫描电镜技术比较分析了球孢白僵菌对单独使用和混配使用下对温室白粉虱若虫的侵染过程。主要研究内容如下:1.球孢白僵菌株系筛选及其对温室白粉虱发育与存活的影响测定了8株供试球孢白僵菌株系对温室白粉虱3龄若虫致病效果,在初步筛选过程中,所有株系均表现出一定的致病力,在孢子悬浮液浓度为1×107个/mL时,校正死亡率为27.0%~70.6%,僵虫率为27.0%~67.5%,同时在上述浓度下进行时间-死亡率线性拟合测得致死中时间为4.9~7.9 d,Bb252株系的校正死亡率、僵虫率显著高于其他株系,因此判定Bb252是对温室白粉虱具有潜在控制作用的优良株系。进一步测定Bb252株系对温室白粉虱的致病力效果,测得LC50值为3.99×106个/mL。球孢白僵菌Bb252株系对温室白粉虱的潜在防控结果表明,1×104、1×105、1×106、1×107、1×108个/mL浓度Bb252孢子悬浮液处理温室白粉虱24 h后,各浓度处理对其取食、产卵行为均有显著影响,且随着浓度的升高而增强,在1×108个/mL浓度下,球孢白僵菌Bb252株系对温室白粉虱的取食忌避率、拒食率、产卵忌避率最高,分别达到78.8%、80.9%、78.7%。温室白粉虱发育历期随着球孢白僵菌Bb252浓度增加而逐渐缩短,在1×108个/mL浓度下,发育历期最短,为20.73±0.30 d,显著低于对照处理下的23.48±0.23 d。利用Kaplan-Meier法分析结果表明在浓度为1×108个/mL作用下,温室白粉虱累积存活率在22 d达到最低值0.482。2.印楝素对温室白粉虱存活与发育的影响测定不同浓度印楝素对温室白粉虱3龄若虫的毒力作用,结果表明印楝素对温室白粉虱3龄若虫的LC50为5.76 mg/L。通过忌避作用、发育历期影响以及生存分析,印楝素在500 mg/L、50 mg/L、5 mg/L、1 mg/L、0.5 mg/L等5种浓度处理24 h后,温室白粉虱拒食率为17.81%~60.11%,产卵忌避率为14.58%~69.64%,且随着浓度的增高忌避作用越明显。经印楝素处理后,烟草叶片不仅可以降低温室白粉虱种群的取食率,取食该叶片后还可导致粉虱发育历期延长,当浓度达到50mg/L时,其发育历期最长为24.95±0.83 d。温室白粉虱在50 mg/L浓度印楝素处理下累计存活率在25 d达到最低值0.432。因此,印楝素对粉虱种群控制作用除直接的致死效应外还具有趋避、拒食以及干扰其生长发育等潜在控制作用。3.球孢白僵菌与印楝素混配使用对温室白粉虱防控效果分析通过球孢白僵菌与印楝素二者的相容性混配试验,利用不同浓度印楝素配制成含毒培养基并接种白僵菌菌饼,结果表明,印楝素浓度在500 mg/L时,对球孢白僵菌的抑制率达到65.3%,当印楝素浓度低于50 mg/L,对其抑制率均小于30%,表明两者相容较好。将印楝素与球孢白僵菌分别以LC50浓度按9∶1、4∶1、1∶1、1∶4、1∶9的比例混配,在1∶1、1∶4比例混配后表现为增效作用,其中1∶4比例下的共毒系数最高为294.23。通过扫描电镜观察单剂与最优混剂中球孢白僵菌孢子萌发及侵染过程,发现白僵菌孢子易在寄主表皮的凹槽、褶皱处附着、萌发,在光滑的背板处则极易脱落。2种剂型对孢子萌发影响差别不大,在48 h内均能够陆续萌发,只有在菌丝营养生长后期,形成网状结构包围寄主时(96 h~120 h),混剂菌丝的网状结构较单剂的稀疏。
[Abstract]:The greenhouse whitefly (Trialeurodes vaporariorum Westwood) is a worldwide agricultural pest. It has a wide distribution and many host characteristics. At present, the production is mainly controlled by chemical pesticides to control its occurrence and harm. Because of the large use of chemical chemicals and the short development period of the greenhouse whitefly, the ecological countermeasures of strong fecundity have led to its resistance to drug. The use of biological control means not only can delay the growth of resistance to insect pests, but also have the advantages of environmental friendly and continuous control. The rational development and use of biological control technology have attracted more and more attention. Therefore, this study carried out the determination of the pathogenicity of Beauveria bassiana and azadirachtin on the greenhouse whitefly, and evaluated two The influence of the people on their development, reproduction and survival, and using scanning electron microscopy to compare and analyze the infection process of Beauveria bassiana to the nymphs of the greenhouse whitefly. The main contents are as follows: 1. screening of Beauveria bassiana and its effects on the development and survival of white Whitefly in greenhouse, 8 test In the preliminary screening process, the strains of Beauveria bassiana had a certain pathogenicity in the preliminary screening process. When the concentration of the spore suspension was 1 x 107 /mL, the correction mortality was 27.0%~70.6% and the rate of ossified insect was 27.0%~67.5%. At the same time, the time mortality linear fitting under the above concentration was used to determine the death rate. The median time was 4.9~7.9 D and the correction mortality of Bb252 strain was significantly higher than that of other strains. Therefore, it was determined that Bb252 was a good plant line with potential control effect on the greenhouse whitefly. The pathogenicity effect of Bb252 strain on greenhouse whitefly was further measured, and the value of LC50 was 3.99 * 106 /mL. of Beauveria bassiana to greenhouse white. The potential control results of whitefly showed that after 1 x 104,1 * 105,1 x 106,1 x 107,1 x 108 /mL concentration Bb252 spores suspension solution treatment of greenhouse white meal louse 24 h, each concentration treatment had a significant effect on its feeding and spawning behavior, and increased with the increase of concentration. At the concentration of 1 x 108 /mL, the Bb252 strain of Beauveria bassiana was taken to the greenhouse whitefly. Avoidance rate, antifeedant rate and oviposition repellent rate were the highest, reaching 78.8%, 80.9% respectively. The development period of 78.7%. greenhouse whitefly gradually shortened with the increase of Bb252 concentration of Beauveria bassiana. Under 1 * 108 /mL concentrations, the development duration was 20.73 + 0.30 D, which was significantly lower than that of the control treated by 23.48 + 0.23 D. using Kaplan-Meier analysis results. Under the action of 1 x 108 /mL, the cumulative survival rate of the greenhouse whitefly reached the lowest value of 22 D. The effect of azadirachtin on the survival and development of greenhouse whitefly was determined by 0.482.2.. The toxicity of azadirachtin to 3 nymphs of greenhouse whitefly was determined by different concentrations. The results showed that the LC50 of azadirachtin for the 3 age nymphs of the greenhouse whitefly was 5.76 mg/L.. After 500 mg/L, 50 mg/L, 5 mg/L, 1 mg/L, 0.5 mg/L, the antifeedant rate of the greenhouse whitefly was 17.81%~60.11%, the oviposition avoidance rate was 14.58%~69.64%, and the deterrent effect was more obvious with the increase of concentration. After treatment with azadirachtin, the tobacco leaves could not only reduce the low temperature. The feeding rate of the Bemisia tabaci population could lead to the prolongation of the development period of the whitefly. When the concentration reached 50mg/L, the longest development period was 24.95 + 0.83 D., the cumulative survival rate of the white powdery Whitefly in the 50 mg/L concentration of azadirachtin reached a minimum of 25 D, so the control effect of azadirachtin to the whitefly population was directly caused by the Azadirachtin. The effect of the death effect also has the potential control effect of avoidance, antifeedant and interference with the growth and development of.3.. The control effect of the mixed use of Beauveria bassiana and azadirachtin on the control of greenhouse whitefly by miscibility test of assius bassiana and azadirachtin two, using different concentrations of azadirachtin into a poisonous medium and inoculated with Beauveria bassiana The results showed that the inhibition rate of azadirachtin at 500 mg/L was 65.3%. When the concentration of azadirachtin was lower than 50 mg/L, the inhibition rate of azadirachtin was less than 30%, indicating that both of them were compatible. The mixture of azadirachtin and Beauveria bassiana was mixed at the concentration of 9: 1,4: 1,1: 1,1: 4,1: 9, respectively, after mixing with 1: 1,1: 4. The CO toxicity of 1 to 4 ratio was the highest of 294.23.. The spore germination and infection process of Beauveria bassiana was observed by scanning electron microscope. It was found that the spores of Beauveria bassiana were easy to be in the grooves of the host epidermis, the folds were attached and germinated, and the spores were easily sprouting out of the.2 forms at the smooth back plate. The difference was not significant, and it could germinate in succession in 48 h. Only in the late growth of the mycelium, the reticular structure surrounded the host (96 h~120 h), and the reticular structure of the mixed mycelium was thinning than that of the single agent.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S433

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