A strain DK49 of high insecticidal activity against Luperomorpha suturalis was screened. Homology of the strain DK49 was compared using gene sequences of gyr B and pho R in Gen Bank separately, which showed high homology (99％) to that of Bacillus thuringiensis. Phylogenetic trees indicated that the strain DK49 is a B. thuringiensis strain. Biolog phenotypic analysis showed that the strain DK49 could effectively absorb 14 carbon sources and was sensitive to 10 chemicals and insensitive to 11 chemicals. Laboratory evaluation of bioactivity determined its 3 d LC50 against L. suturalis adult to be 0.8161×107 cfu/mL. Field assays with 3 continuous sprays at 1×107 cfu/mL showed a control efficiency of 96.81％ against L. suturalis. Therefore the strain DK49 has a potential for field control of L. suturalis.%本研究筛选到一株对葱黄寡毛跳甲具有较高杀虫活性的菌株DK49,利用菌株DK49 gyr B基因序列和pho R基因序列分别在Gen Bank中进行同源性比较,两种基因序列均与苏云金芽胞杆菌的相应基因序列同源性最高,达到99％;同时分别构建系统发育树,发现菌株DK49均与苏云金芽胞杆菌聚合在一起,说明菌株DK49属于苏云金芽胞杆菌.Biolog表型分析结果显示菌株DK49可有效利用14种碳源,对二甲胺四环素等10种化学物质敏感,对利福霉素等11种化学物质不敏感.通过室内生物活性评价,明确菌株DK49对葱黄寡毛跳甲成虫3 d的LC50为0.8161×107 cfu/mL.田间小区结果显示,菌株DK49在1×107 cfu/mL浓度下,连续施药3次后对葱黄寡毛跳甲的虫口减退率达到92.31％,防治效果达到96.81％.可见,菌株DK49能有效地控制葱黄寡毛跳甲的发生为害,具有良好的应用前景.
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