白僵菌对盲蝽的致病性

我国棉花盲蝽的发生危害日益严重,而化学防治是当前控制这类害虫的唯一有效途径.为了探索盲蝽的微生物防治技术,在室内条件下利用浸虫法评价了7个白僵菌菌株对我国3个盲蝽优势种类--绿盲蝽、中黑盲蝽和苜蓿盲蝽的致病能力.结果显示,不同菌株对不同种类盲蝽的致病效果存在较大差异,菌株C-1对绿盲蝽的致病力优于对中黑盲蝽和苜蓿盲蝽,菌株07-2-3、07-10-10、07-10-11、07-10-12和07-10-14对中黑盲蝽和苜蓿盲蝽的致病力优于对绿盲蝽.在7个菌株中,C-1对绿盲蝽2龄若虫的致病力最强,其LC50为5.34×106个孢子/mL.菌株C-1的致病力随着绿盲蝽若虫龄期的增加而减弱.在浓度为1×107个孢子/mL时,菌株C-1对绿盲蝽2～4龄若虫的致死中时间分别为7.11、8.37和12.44天;在浓度为1×108个孢子/mL时,分别为3.14、3.87和4.95天.研究表明,白僵菌在防治我国棉花盲蝽方面具有较大的应用潜力.

Pathogenicity of Beauveriaspp. strains to three species of mirids, Apolygus lucorum, Adelphocoris suturalisand Adelphocoris lineolatus

The mirids are causing increasing damage in Chinese cotton production, and chemical control is almost the exclusive management option for these pests at present. In order to develop microbial control measure, the pathogenicity of seven strains of Beauveria spp. to three dominant mirid species, Apolygus lucorum, Adelphocoris suturalis and Adelphocoris lineolatus was assessed in the laboratory. The results showed that the pathogenicity of each strain varied greatly with mirid species. The strain C-1 had the greater pathogenicity against A.lucorum than A.suturalis and A.lineolatus, whereas the strains 07-2-3, 07-10-10, 07-10-11, 07-10-12 and 07-10-14 were highly effective against A.suturalis and A.lineolatus than A.lucorum. Among all the tested strains, C-1 had the greatest pathogenicity against the 2nd instar nymphs of A.lucorum with the LC₅₀ value of 5.34×10⁶ conidia/mL. Additionally, the pathogenicity gradually lowered with the increasing age of A.lucorum nymphs. At a concentration of 1×10⁷ conidia/mL, the LT₅₀ values of the strain C-1 against the 2nd, 3rd and 4th instar nymphs were 7.11, 8.37 and 12.44 d, respectively, and those were 3.14, 3.87 and 4.95 d at 1×10⁸ conidia/mL. The Beauveria spp. has the potential of being used in microbial control of cotton mirids in China.