桑天牛幼虫高毒力白僵菌菌株筛选(英文)

Screening Test of Highly Virulent Strains of Entomopathogenic Fungi Beauveria bassiana against Apriona germari Larvae

为利用白僵菌防治桑天牛,从野外感病死亡昆虫体上进行分离,同时利用黄粉虫对河北省土壤中的白僵菌进行诱集。诱集结果表明:白僵菌较多存在于自然的或人为活动较少的土壤中。利用获得的菌株对桑天牛幼虫进行生物测定,初步筛选出Bi05和Bs042个致病力较强的菌株,其接种10d后的死亡率分别为96.47%和92.93%,致死中时分别为4.53d和4.83d,而其他菌株的死亡率在28.59%和82.12%之间,致死中时从5.84d到16.4d。利用不同孢子浓度的悬浮液对桑天牛幼虫进行接种,进一步测定了Bi05和Bs04菌株的致死中浓度分别为6.76×105和1.39×106conidia·mL-1。Bi05和Bs04菌株具有生物防治桑天牛的潜力。

To develop microbial control of Apriorta germari, a destructive stem-boring pest, Beauveria bassiana were isolated from infected insects obtained in the field and by the bait method from soil samples in Hebei Province. The bait results showed that B. bassiarta occurred more frequently in the natural and undestroyed soils. The virulence of all isolates was tested in bioassays by dipping larvae in 1 × 10^8 conidia· mL^-1 suspensions. Two isolates Bi05 and Bs04 with the shortest LT50 value（4.53 d and 4.83 d） caused 96.47% and 92.93% mortality（due to B. bassiana）respectively 10 d post-inoculation while other isolates only caused mortalities from 28.59% to 82.12% with LT50 value ranged from 5.84 d to 16.4 d. The virulence of Bi05 and Bs04 was further tested by exposing A. germari larvae to conidial serial concentrations of 1 × 10^4～ 1× 10^8 conidia· mL^- 1·LC50 value of Bi05 and Bs04 were 6.76 × 105 and 1.39 × 10^6 conidia· mL^-1, respectively. The present results suggest that the isolate Bi05 and Bs04 has excellent potential for biological control of A. germari.