一株玫烟色虫草对草地贪夜蛾的致病性研究  

Pathogenicity study of a strain of Cordyceps fumosorosea to Spodoptera frugiperda (Lepidoptera: Noctuidae)

作　　者：雷妍圆[1] 吕利华[1] 王裕华 王德森 LEI Yan-Yuan;LU Li-Hua;WANG Yu-Hua;WANG De-Sen(Guangdong Provincial Key Laboratory of High Technology for Plant Protection,Institute of Plant Protection,Guangdong Academy of Agricultural Sciences,Guangzhou 510640,China;College of Agriculture,South China Agriculture University,Guangzhou 510642,China)

机构地区：[1]广东省农业科学院植物保护研究所,广东省植物保护新技术重点实验室,广州510640 [2]华南农业大学农学院,广州510642

出　　处：《环境昆虫学报》2020年第1期68-75,共8页Journal of Environmental Entomology

基　　金：草地贪夜蛾防控关键技术研究与集成示范(2019YFD0300104);国家重点研发计划(2017YFC1200600);广东省现代农业产业共性关键技术研发创新团队“外来入侵物种风险评估和监测预警”;广东省现代农业产业技术体系创新团队(2017LM1078)

摘　　要：草地贪夜蛾Spodoptera frugiperda(J.E Smith)是我国新发现的一种重要外来入侵害虫。为了寻找对草地贪夜蛾有致病性的昆虫病原真菌,本实验采用浸虫法研究了玫烟色虫草Cordyceps(=Isaria)fumosorosea SCAU-IFCF01对草地贪夜蛾1~6龄幼虫的致病力,通过体视镜观察了幼虫感菌后侵染症状和体表病变过程。结果表明:菌株IFCF01可侵染草地贪夜蛾6个龄期的幼虫。4龄幼虫接种后48 h,虫体出现缩短、强直等形态变化;接种后72 h,幼虫死亡且体外形成菌丝层;接种后120 h,虫体被浅玫烟色的分生孢子覆盖。随孢子浓度的升高,幼虫的感病死亡率增加,当浓度达到1×109孢子/mL时,1~3龄幼虫的累计死亡率均为100%,4龄幼虫和5龄幼虫也达到了98.9%和50%,6龄幼虫仅21.1%。5 d后1~5龄幼虫的LC 50值分别为3.74×104、1.17×105、1.86×105、8.09×105和3.03×108孢子/mL。幼虫LT 50值随孢子浓度增加而递减,在浓度为1.0×105~1.0×109孢子/mL的范围内,1龄幼虫和2龄幼虫的LT 50值分别为3.62~1.37 d和4.51~1.65 d;在1.0×106~1.0×109孢子/mL时,对3龄幼虫的LT 50为4.03~1.82 d;浓度为1.0×107~1.0×109孢子/mL时,对4龄幼虫的LT 50为3.47~2.52 d。浓度为1.0×109孢子/mL时,5龄幼虫的LT 50为4.74 d。本研究结果表明,玫烟色虫草菌株IFCF01对草地贪夜蛾幼虫具有较强的致病力,为今后草地贪夜蛾微生物防治提供重要的有效真菌。The fall armyworm,Spodoptera frugiperda(J.E Smith)(Lepidoptera:Noctuidae),is a new invasive pest to China.To understand the pathogenic effect of the entomopathogenic fungus Cordyceps fumosorosea(renamed from Isaria fumosorosea)to S.frugiperda,the pathogenicity of C.fumosorosea strain SCAU-IFCF01 to S.frugiperda larvae was studied in laboratory by immersing larvae of different instars into serial concentrations of conidial suspension.The external symptoms of infected larvae were observed under light microscope as well.The results showed that larvae from 1 st to 6 th instar were infected by C.fumosorosea strain IFCF01.The whole body surface of 4 th instar larvae thickened and reduced in size after 48 h post inoculation.Hyphae colonized and emerged around the cadavers after 72 h post inoculation.Whole insect body covered with aerial mycelium and conidia after 120 h post inoculation.The mortality rates of the S.frugiperda caused by infection of C.fumosorosea increased with the concentration of conidial suspension and the time after treatment.The highest concentration(1×109 conidia/mL)treatment caused 100%,100%,100%,98.9%,50%,and 21.1%mortality for 1 st to 6 th instar larvae on the 5 th day,respectively.The estimated LC 50 values of 1 st to 5 th instar larvae on day 5 after treatment were 3.74×104、1.17×105、1.86×105、8.09×105 and 3.03×108 conidia/mL,respectively.Values of LT 50 of all tested instars were shortened with concentration.The LT 50 values of 1 st and 2 nd instar were 3.62~1.37 d and 4.51~1.65 d,respectively,in the range of 1×105~1×109 conidia/mL.The LT 50 values of 3 rd instar were 4.03~1.82 d in the range of 1×106~1×109 conidia/mL.The LT 50 values of 4 th instar were 3.47~2.52 d in the range of 1×107~1×109 conidia/mL.The LT 50 value of 5 th instar was 4.74 d in 1×109 conidia/mL.The results suggested the potential of the C.fumosorosea strain IFCF01 for use in microbial control of S.frugiperda.

关 键 词：玫烟色虫草 草地贪夜蛾 侵染症状 致病力 微生物防治 

分 类 号：Q965.9[生物学—昆虫学] S433.4[农业科学—农业昆虫与害虫防治]