3种丝孢虫生真菌对西花蓟马成虫的毒力测定

Virulence of three hyphomycetes entomopathogenic fungi against the adult of Frankliniella occidentalis(Pergande)

【目的】测定3种丝孢类虫生真菌对西花蓟马[Frankliniella occidentalis(Pergande)]成虫的毒力,为筛选出对西花蓟马成虫高毒力的虫生真菌及生物防治提供依据。【方法】采用浸渍法在室内测定3种丝孢虫生真菌(球孢白僵菌、黄绿绿僵菌和玫烟色棒束孢)共14株菌株对西花蓟马成虫的侵染致死率;从3种丝孢虫生真菌中选取对西花蓟马成虫相对致病力较好的高毒力菌株各1株,测定其在不同浓度(浓度梯度分别为1.0×10^4、1.0×10^5、1.0×10^6、1.0×10^7和1.0×10^8孢子/mL)下对西花蓟马成虫的毒力。【结果】用1.0×10^7孢子/mL的球孢白僵菌菌株(WSWM81832、WSWL21831、WSWM1018315、WSWH21833和WSWL21836)、黄绿绿僵菌菌株(HLT17103、NGS21751、YKZ51712和WSWL51721)和玫烟色棒束孢菌株(WSWH31836、WSWL51831、WTS101822、NGS118310和WSWL21837)接种西花蓟马成虫10 d后,西花蓟马成虫的累积校正死亡率分别为68.45%~75.60%、67.35%~82.65%和61.45%~70.67%。球孢白僵菌WSWL21836、黄绿绿僵菌WSWL51721和玫烟色棒束孢WSWL21837菌株以1.0×10^4~1.0×10^8孢子/mL的孢子悬浮液接种西花蓟马成虫后,第10 d时西花蓟马成虫的累积校正死亡率分别为56.67%~82.33%、56.67%~89.67%和48.33%~76.67%;各菌株的毒力回归方程分别为Y=3.2543+0.3332X(r=0.9167)、Y=3.5878+0.2874X(r=0.9656)和Y=3.8188+0.2082X(r=0.9925),致死中浓度(LC50)分别为2.63×10^4、4.17×10^4和7.85×10^5孢子/mL,在1.0×10^8孢子/mL浓度下对西花蓟马成虫侵染致病的致死中时间(LT50)分别为5.67、4.91和6.12 d。【结论】黄绿绿僵菌菌株WSWL51721和球孢白僵菌菌株WSWL21836对西花蓟马成虫具有较强的毒力,可作为西花蓟马生防制剂开发的潜力菌株。

【Objective】The virulence of three hyphomycetes entomopathogenic fungi against the adult western flower thrips,Frankliniella occidentalis(Pergande)was studied to provide basic information for the selecting of high virulent entomopathogenic fungi and biological control for the adult F. occidentalis.【Method】Immersion method was used to test the virulence of three entomopathogenic fungi(Beauveria bassiana,Metarhizium flavoviride and Isaria fumosorosea)against the F. occidentalis adults under laboratory condition,and based on the fourteen isolates tested,three high infective and lethal rates strains(B. bassiana WSWL21836,M. flavoviride WSWL51721,I. fumosorosea WSWL21837)were selected against the F. occidentalis adults at different concentrations(1.0×10^4,1.0×10^5,1.0×10^6,1.0×10^7 and 1.0×10^8 spore/mL).【Result】After 10 d of F. occidentalis adults were inoculated with 1.0×10^7 spore/mL of B. bassiana strains(WSWM81832, WSWL21831,WSWM1018315,WSWH21833 and WSWL21836),M. flavoviride strains(HLT17103,NGS21751, YKZ51712 and WSWL51721)and I. fumosorosea strains(WSWH31836,WSWL51831,WTS101822,NGS118310 and WSWL21837),the cumulative corrected mortality rates of F. occidentalis adults were 68.45%-75.60%,67.35%-82.65%,and 61.45%-70.67%,respectively. The virulence of B. bassiana WSWL21836,M. flavoviride WSWL51721 and I. fumosorosea WSWL21837 to F. occidentalis adults were inoculated with spore suspension at the concentration of 1.0×10^4 to 1.0× 10^8 spores /mL. On the 10th day,the cumulative corrected mortality rates of F. occidentalis adults were 56.67%-82.33%, 56.67%- 89.67% and 48.33%- 76.67%,respectively. The virulence regression equations of each strain were Y=3.2543+ 0.3332X(r=0.9167),Y=3.5878+0.2874X(r=0.9656)and Y=3.8188+0.2082X(r=0.9925),respectively,and the median lethal concentrations(LC50)were 2.63×10^4,4.17×0^4 and 7.85×10^5 spores/mL,the median lethal time(LT50)of infected F. occidentalis adults were 5.67,4.91 and 6.12 d with the concentration of 1.0×10^8 spores/mL,respectively.【Conclusion】The strains M. flavoviride WSWL51721 and B. bassiana WSWL21836 have strong virulence to F. occidentalis adults,and can be used as a biological control agent in an integrated pest management program.