【作者】 吴圣勇；

【导师】 雷仲仁；

【作者基本信息】 中国农业科学院 ， 农业昆虫与害虫防治， 2014， 博士

【摘要】 为了提高对单一害虫的生物防治效果和减少经济损失，生防工作者提出多天敌联合应用的策略。经过多年的科研实践，该策略逐渐成为一个热议的话题，备受争议。由于天敌之间可能存在的兼性捕食或寄生作用、对资源的掠夺性竞争和拮抗等关系，因此，多天敌的兼容性和如何协调使用成为联合应用能否取得成功的关键。本论文以外来入侵害虫西花蓟马为防治对象，通过筛选高毒力的球孢白僵菌菌株，并引入一种对西花蓟马具有较高防治潜力的国内优势捕食螨品种——巴氏新小绥螨，在室内和温室开展了这几者之间的互作关系研究，从多角度评价白僵菌和捕食螨的兼容性以及二者联合应用的潜力和方法。研究的主要内容如下：一、白僵菌、巴氏新小绥螨和西花蓟马两两互作关系研究生测法筛选出了一种对西花蓟马具有高毒力的菌株，并测定了不同浓度和不同持续时间的白僵菌孢子液对西花蓟马的毒力作用。用扫描电镜方法比较了高毒力菌株对西花蓟马成虫和巴氏新小绥螨成螨的侵染过程，发现白僵菌处理西花蓟马成虫后，孢子在60h内可以完成体表附着、萌发、穿透体壁和成功入侵的整个过程，进一步表现出对西花蓟马具有较高的毒力作用；对巴氏新小绥螨进行同样处理后，白僵菌孢子可以在其体壁完成附着和萌发阶段，但不能穿透捕食螨体壁，表明捕食螨对白僵菌的侵染具有防御能力。通过定性和定量两个方面，研究了巴氏新小绥螨携带白僵菌孢子防治西花蓟马成虫的能力，并研究了其所携带孢子的数量和活力，结果表明由于捕食螨行为的影响，导致其携带和传播孢子的能力有限。用白僵菌处理后的雌成螨，其产卵前期显著延长。试验还发现捕食螨具有直接取食白僵菌孢子的现象。二、白僵菌、巴氏新小绥螨和西花蓟马三者互作关系研究用功能反应方法，研究被白僵菌处理的巴氏新小绥螨对西花蓟马初孵若虫的捕食能力，结果表明捕食螨的捕食能力不受白僵菌影响，且捕食螨对被白僵菌侵染12h后的蓟马若虫的捕食量增加。通过室内模拟和生测方法，发现被捕食螨攻击过的蓟马2龄若虫和蛹，容易被白僵菌侵染。通过测定捕食螨对白僵菌的趋性反应，表明无论有无蓟马的引诱，捕食螨都对白僵菌孢子液处理0和12h后的菜豆叶片具有明显的排斥反应。通过两性生命表研究，巴氏新小绥螨取食被菌侵染的蓟马若虫后，生命表参数变化显著，表明白僵菌对捕食螨具有间接影响。三、温室单独和联合应用白僵菌和巴氏新小绥螨防治西花蓟马通过在温室中设置不同的处理，研究单独、同时联合和间隔联合应用白僵菌和捕食螨对西花蓟马的防治效果，结果表明白僵菌和捕食螨同时联合应用时，二者之间具有明显的交互作用，从而抑制了联合应用的效果，而间隔联合应用能够起到对西花蓟马的增效防治作用。因此，建议白僵菌和捕食螨在田间采取间隔联合应用的方式。更多还原

【Abstract】 In order to improve biocontrol effect on single target pest and minimize economic losses, multiplenatural enemies to be integrated has been recommended in the IPM strategy. However, the issue ofbenefits of introducing single or multiple natural enemy species for classical biological control hasbecoming controversial after many years of scientific practice. Since the intraguild predation (IGP),resource competition and antagonism exist among enemies, a better understanding of the interactionsamong multiple natural enemy species would improve their integration into pest management practices.This paper investigated the interactions between Beauveria bassiana and predatory miteNeoseiulus barkeri for the control of their target pest, Frankliniella occidentalis, one of the mostimportant insect pests in ornamentals and vegetables worldwide. Neoseiulus barkeri is distributedwidely and displayed potential for biological control of several species of thrips. Beauveria bassianawas demonstrated potential in managing F. occidentalis. Our study was conducted in laboratory andgreenhouse to evaluate the compatibility between B. bassiana and N. barkeri and the potential use of B.bassiana in combination with N. barkeri for the control of F. occidentalis.1. Interaction between B. bassiana, N. barkeri and F. occidentalisWe screened one of the most virulent strains against F. occidentalis from30new fungal isolates. Thedirect toxicity of different concentration of B. bassiana and the residual toxicity at different time to F.occidentalis were tested. We compared the fungal infection process in the predator and thrips byscanning electron microscopy. The results revealed that B. bassiana successfully infected F. occidentaliswithin60h. In contrast, we never observed penetration of the cuticle of N. barkeri. Neoseiulus barkeridisplayed effective defense against B. bassiana. The ability of conidia carried by N. barkeri and thevitality of conidia were tested, and the results showed that the treated N. barkeri can carry a largenumber of conidia within a short time, the conidia can be dispersed and infected F. occidentalis, andthese synergistic effects were rapidly weakened by the self-grooming behavior of N. barkeri. We alsofound that the preoviposition duration of the female N. barkeri was significantly longer and conidiacould be fed by N. barkeri.2. Interaction among B. bassiana, N. barkeri and F. occidentalisFrom functional response and bioassay experiments, we showed that the predation capability of N.barkeri was not affected by B. bassiana. The first instar larvae of F. occidentalis after having beentreated with the fungus for12h were more vulnerable to be killed by N. barkeri. Second instar larvaeand pupae of F. occidentalis which had been attacked by N. barkeri were more susceptible to B.bassiana infection. When treated the leaves of kidney bean with B. bassiana solution, N. barkeridisplayed behavioral repellence. From two-sex life table study, we found that the life table parameters ofN. barkeri were strongly affected when fed on infected F. occidentalis.3. Application of B. bassiana and N. barkeri for controlling F. occidentalis in greenhouse.We determined the effects of single and combined application of B. bassiana and N. barkeri forcontrolling F. occidentalis in cucumber greenhouse experiments. The results indicated that there were obvious interactions between B. bassiana and N. barkeri with little synergistic effects for F. occidentalisbiological control when combined both simultaneously, so the application of B. bassiana in combinationwith N. barkeri at certain intervals was suggested.更多还原