球孢白僵菌对马铃薯块茎蛾的毒力及其与常用农药的生物相容性测定

室内测定了从云南分离的7株球孢白僵菌对马铃薯块茎蛾幼虫的毒力,结果表明,在接菌孢子浓度为10⁵个/mL和10⁷个/mL下,接种后7d马铃薯块茎蛾幼虫累积死亡率分别为23.3%～70.0%和33.3%～86.7%,添加吐温80的清水对照死亡率仅为3.3%。筛选出毒力较高的Bb7001、Bb7004、Bb8001 3个菌株,其中菌株Bb8001对马铃薯块茎蛾幼虫的毒力最高,在孢子浓度1×10⁵、1×10⁷个/mL下,第7天的累计死亡率分别为70.0%和86.7%,其毒力回归方程Y=0.366X+3.409(R=0.956),剂量效应LC₅₀=2.24×10⁴个/mL,孢子浓度10⁷个/mL下的LT₅₀为4.3d。测定了毒力较高的菌株与12种农药的生物相容性,结果表明在供试农药推荐用量及其101、00倍稀释液下,球孢白僵菌Bb7001、Bb7004、Bb8001的3个菌株孢子在含所选农药的营养液中生物相容性良好的农药有:苏云金芽孢杆菌可湿性粉剂(Bt)、10%吡虫啉可湿性粉剂、2.5%菜喜悬浮剂及松毛虫病毒可湿粉剂,可配伍使用;而阿维菌素、农安、卡死克、抑太保对球孢白僵菌有很强的抑制作用,应避免配伍使用。

Relative virulence of seven isolates of Beauveria bassiana to the potato tuber moth, Phthorimaea opercula (Zeller) and their biological compatibility with ten insecticides

The virulence of seven strains of Beauveria bassiana, namely Bb2001, Bb4014, Bb4015, Bb7001, Bb7002, Bb 7004 and Bb8001 that are originated from the cadavers of the larvae of potato tuber moth (PTM), Phthorimaea operculella (Zeller) in Yunnan was studied. The results showed that all of the tested strains were virulent to the larvae of PTM and the cumulative mortality ranged between 23.3% and 70.0% in the 7th day after inoculation at the concentration of 10~5conidia/ml. Strain Bb7001, Bb 7004 and Bb 8001 have higher virulence to the larvae of PTM than other strains, especially strain Bb8001, which caused the highest mortality of PTM and the cumulative mortality of which in the 7th day after inoculation at the concentration of 10~5conidia/ml and 10~7conidia/ml was 70.0% and 86.7%, respectively. So strain Bb7001, Bb 7004 and Bb8001 were selected as potential entomopathogenic fungi for further study. The compatibility of strain Bb7001, Bb7004 and Bb8001 with 10 widely used pesticides were assayed using 24h-liquid culture, containing 0.01, 0.1 and 1.0 fold of the recommended concentrations for field sprays. The results showed that the germination of B. bassiana conidia varied with the pesticides tested. Bt WP, Imidacloprid 10%WP, Spinosad 2.5%SC and the Dendrolimus virus WP were compatible with the three selected strains of B. bassiana originated from the PTM, but other pesticides showed inhibitory effects on the germination of the strains of B. bassiana, especially atabron 5%EC, abamectin 2.0%EC, cascade 5%DC, which showed intense inhibitory activity to the germination of the selected strains of B. bassiana so they shouldn't be used together with the biological control agents.