For screening excellent biocontrol strains of rice water weevil,four B.bassiana strains from different sources were bioassayed against the rice water weevil in 2.0 × 104 spores/mL,2.0 × 105 spores/ mL,2.0 × 106 spores/mL,2.0 × 107 spores/mL and 2.0 × 108 spores/mL concentration gradients of spore suspension with 0.1％Tween-80 bacteria free water.After application of strains,the deaths of rice water weevil were observed in 5 d,7 d,10 d and 15 d.The results showed that time and concentration effects of the strains showed negative trends and the most virulent to the rice water weevil was YS03 compared with others.The strain caused 96.55％ of rice water weevil dead at 26C 15 days after inoculating at a concentration of 2.0 × 108 spores/mL.The results showed that the strain YS03 is highly toxic to rice water weevil and has the potential for use in biological control of the insect pest.%为了筛选出防治稻水象甲优效的生防菌株,利用不同来源的4株球孢白僵菌(Beauveria bassiana)菌株,分别用0.1％Tween-80无菌水配制成5个不同的孢子浓度(2.0×104个/mL,2.0×105个/mL,2.0×106个/mL,2.0×10 7个/mL,2.0×108个/mL)的菌株对稻水象甲成虫进行室内生物测定.在施茵后5d、7d、10 d、15d分别观察稻水象甲成虫的死亡情况.结果表明:各菌株的时间效应与浓度效应呈负相关趋势,并筛选出对稻水象甲成虫毒力最强的YS03菌株.该菌株在孢子浓度为2.0×I08个/mL接种处理后,26.C条件下第15天供试成虫平均校正死亡率达96.55％,显示出对靶标害虫具有较好的毒力,在稻水象甲的生物防治中具有潜在的应用价值.
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