白僵菌对西花蓟马若虫的致病力和对巴氏钝绥螨的影响

本文测定了5株球孢白僵菌Beauveriabassiana对西花蓟马Frankliniellaoccidentalis1龄若虫的致病力，获得3株毒力较高的菌株：TL．7、sz．15和RSB，在1×10^8孢子．mL^-1浓度下的西花蓟马l龄若虫死亡率分别为90．8％、92．5％和100％；结合测定的致死时间与致死浓度，得出菌株RSB为最优菌株（LT50为2．383d，LC50为1．53X10’孢子．mL^-1）。以西花蓟马1龄若虫为猎物，测定菌株RSB对其天敌巴氏钝绥螨Amblyseiusbarkeri的影响。结果表明：用菌株RSB（1×10’孢子．mL^-1）处理的巴氏钝绥螨可发育为成螨；发育历期、雌成螨寿命和平均每雌每天产卵量分别为5．9d、33．850d和1．78粒，与对照均差异不显著，说明西花蓟马的高效白僵菌菌株RSB对其天敌巴氏钝绥螨不存在显著的负面影响。本文结果表明白僵菌可在田间与巴氏钝绥螨协同控制重大外来入侵害虫西花蓟马。

Virulence of Beauveria bassiana Isolates against the First Instar Nymphs of Frankliniella occidentalis and Effects on Natural Enemy Amblyseius barkeri

Virulence of five Beauveria bassiana isolates against the first instar nymph ofFrankliniella oceidentalis was evaluated in this study. Three isolates TL^-7, SZ%-15 and RSB were highly virulent to the first instar nymph with 90.8%, 92.5% and 100% mortality at the dose of 1 ×^108 conidia-mL-1, respectively. Among the five isolates, isolate RSB was the most virulent, with LTs0value of 2.383 d and LCs0value of 1.53 × 103 conidia.mL-1. The non-target effects of RSB on Amblyseius barkeri, an important predator ofF. occidentalis, were investigated. Results showed that RSB （ 1 × 10^7 conidia .mL-^1 ）-treated A. barkeri could develop into adult stage. RSB did not significantly reduce the development duration, fecundity and longevity of A. barkeri compared to control, with the development duration of 5.9 d, fecundity of 33.850 d and longevity of 1.78 individual, indicating that the isolate RSB had no significant negative effects on the non-target predator A. barkeri. All the data above suggested that B. bassiana combined used with A. barkeri would be potential for the control ofF. occidentalis under field conditions.