苏云金芽孢杆菌YJ-2000菌株对家蚕主要生物学特性影响的研究

苏云金芽孢杆菌YJ 2 0 0 0菌株对多种鳞翅目害虫具明显杀虫活性而对家蚕蚁蚕表现低毒性。以对家蚕蚁蚕表现高毒性的苏云金芽孢杆菌CRY1Ab和YJ 1999菌株为对照 ,研究了苏云金芽孢杆菌YJ 2 0 0 0菌株对家蚕的生物学安全性。YJ 2 0 0 0菌株除导致 1龄幼虫历期延长 11 1%、取食量减少 0～ 6 0 0 %及体重降低 5 2 3%～ 6 2 5 %外 ,对 2龄及其以后各龄幼虫的存活率、发育历期、取食量、眠蚕体重、化蛹率、蛹期、全茧量、蛹重、茧层量、羽化率和产卵量等均无显著影响。相比之下 ,CRY1Ab和YJ 1999菌株则不同 ,高浓度会导致全部蚁蚕死亡 ,呈现高急性毒性 ;低浓度虽不能使幼虫全部死亡 ,但对幸存幼虫的取食、生长发育、结茧和产卵等大多呈现明显的不良影响。综合分析认为 :YJ 2 0 0 0菌株对家蚕不仅低毒 ,而且对其生长发育、结茧和生殖力等均无明显的不良影响。

Effect of Bacillus thuringiensis Strain YJ-2000 on Common Biological Characters of the Domestic Silkworm,Bombyx mori

The biological safety of Bacillus thuringiensis (Bt) Strain YJ-2000 which acted the low toxicity to Bombyx mori newly hatched larvae and marked insecticidal activity to other lepidopterous insects was evaluated compared with other two Bt strains,i.e. CRY1Ab and YJ-1999 with high toxicity to Bombyx mori newly hatched larvae.As compared with those of the control,the survival rate,stadia,feeding amount and molter body weight of 2nd instar and more older larvae,pupation rate,pupal span,cocoon weight,pupal weight,cocoon shell weight,emergence rate and amount of laid eggs were not affected after treatment with Bt YJ-2000,except that about 11.1% in the stadia,0～60.0% in feeding amount and 52.3%～62.5% molter body weight of lst instar larvae were markedly lengthened,minimized and lightened,respectively.In contrast,CRY1Ab and YJ-1999 could cause all newly hatched larvae dead as treated at high concentration.They could not kill all newly hatched larvae as treated at low concentration,however perform marked negative effects on growth and development,cocooning and oviposition of the survived larvae,which were restored from CRY1Ab or YJ-1999 treatment at low concentration,at most cases.It was concluded that YJ-2000 not only showed low toxicity to the silkworm,but also acted no marked negative impacts on growth and development,cocooning as well as fecundity of the silkworm.