不同绿僵菌菌株对筛胸梳爪叩甲幼虫的毒力测定

Virulence Bioassay of Different Metarhizium Strains Against Melanotus cribricollis Larvae

竹林金针虫是南方竹林笋期最为重要的害虫之一,筛胸梳爪叩甲幼虫是竹林金针虫的优势种群,应用绿僵菌防治具有重要意义。测定了3株绿僵菌对筛胸梳爪叩甲幼虫的毒力,并比较了毒土法和毒饵法两种施菌方式对绿僵菌致病力的影响。结果表明,平沙绿僵菌WP08菌株和金龟子绿僵菌30104菌株对筛胸梳爪叩甲幼虫具有明显的致病效果,在30 d的试验期内,校正累计死亡率分别为90.0%和66.3%,半数致死时间(LT50)分别为15.8 d和25.8 d;毒土法的校正累计死亡率略高于毒饵法,分别为60.1%和52.0%,LT50分别为22.6 d和28.0 d。金龟子绿僵菌LRC112菌株对金针虫无致病力。

The bamboo wireworm Melanotus cribricollis is a devastating pest of underground bamboo shoots in south- ern China. To explore an alternative control strategy with fungal biocontrol agents, the authors bioassayed the viru- lence of three Metarhizium strains against Melanotus cribricollis larvae （ 120 - 150 mg per capita） in small cups filled with 50 g soil containing 5 - 106 conidia per gram of soil. The application of the stains Metarhizium pingshaense WP08 and Metarhizium attisopliae 30104 resulted in the corrected mortalities of 90.0% and 66.3% during a 30 - day period under controlled conditions, respectively, whereas Metarhizium anisopliae LRC112 showed no lethal effect on the larvae. Time-mortality analysis led to the median lethal time （LT50） estimates of 15.8 and 25.8 days for the two virulent strains. The high-virulence strain Metarhizium pingshaense WP08 was further assayed for its le- thal effect on the larvae in contact of conidia mixed with corn bait and soil respectively. As a result, the soil mixture caused higher mortality （60.1% ） and shorter LT50 （22.6 days） than the bait mixture （52.0% ; 28.0 days）.