不同绿僵菌菌株对筛胸梳爪叩甲幼虫的毒力测定

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。

Virulence Bioassay of Different Metarhizium Strains Against Melanotus cribricollis Larvae

The bamboo wireworm Melanotus cribricollis is a devastating pest of underground bamboo shoots in southern China. To explore an alternative control strategy with fungal biocontrol agents, the authors bioassayed the virulence 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 anisopliae 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 lethal 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).