用球孢白僵菌和粉拟青霉防治美国白蛾的研究

美国白蛾下树化蛹的过程为昆虫病原真菌与之接触侵染提供了有利环境。从来源于河北、北京地区的22株球孢白僵菌和2株粉拟青霉菌中,筛选出对美国白蛾高致病力的球孢白僵菌菌株FD和粉拟青霉菌株SH9-4,通过爬行接触接种的方法,测定了它们对进入下树化蛹过程的美国白蛾老熟幼虫的侵染效果。研究表明,接种144 h后,白僵菌校正致死率92.4%,LT50为87.06 h;粉拟青霉校正致死率94.9%,LT50为92.34h;受感染的老熟幼虫多在预蛹阶段死亡。同时,对生产出的白僵菌和粉拟青霉的固体菌剂,通过在树干基部施菌的方法进行了小规模的野外防治试验。结果表明,白僵菌和粉拟青霉对越冬代美国白蛾幼虫的防治效果分别为72.9%和83.5%,对第2代美国白蛾幼虫的防治效果分别为88.4%和87.0%。表明针对美国白蛾下树化蛹进行防治是用真菌防治美国白蛾可行的途径。

Elementary Study on Control of Hyphantria cunea by Beauveria bassiana and Paecilomyces farinosus

The process of the mature larva of Hyphantria cunea crawls down the trees to ground to look for suitable place for pupation provides time and environment for entomopathogenic fungal pathogen to contact with infect H.cunea.In the study,highly pathogenic Beauveria bassiana strains FD and Paecilomyces farinosus strains SH9-4 were screened from 22 strains of B.bassiana and 2 strains of P.farinosus,which were collected or baited from Hebei and Beijing.The pathogenicity of B.bassiana strains FD and P.farinosus strains SH9-4 on mature larvae were determined by crawling contact inoculation method in this research.144 h after inoculation,the corrected mortality of B.bassiana against mature larvae was 92.4%,and LT50 was 87.06 h.And the corrected mortality of P.farinosus against H.cunea mature larvae was 94.9%,and LT50 92.34 h.Most of infected larvae could not finish pupation process,and usually died in pre-pupae instar.Soil agents of B.bassiana and P.farinosus were applied around trunk base in field control experiments.Control efficacy of B.bassiana and P.farinosus to overwintering generation of H.cunea was 72.9% and 83.9%,and to the 2nd generation was 88.4% and 87.0% respectively.These results indicated that applying soil agents for pupation process was a feasible way to control H.cunea by pathogenic fungi.