宿主湿度环境对球孢白僵菌致病力的影响  

Effects of host’s environmental humidity on pathogenicity of Beauveria bassiana

作　　者：唐亮 石美宁 朱方容 潘志新 黄旭华 胡文娟 黄深惠 

机构地区：[1]广西蚕业技术推广总站 [2]广西蚕业科学研究院,南宁530007

出　　处：《南方农业学报》2013年第7期1210-1214,共5页Journal of Southern Agriculture

基　　金：广西科学研究与技术开发计划项目(桂科攻1123002-5)

摘　　要：【目的】研究宿主湿度环境对球孢白僵菌致病力的影响,为采取适当防治措施以减少白僵病对蚕茧生产的危害提供参考依据。【方法】以广西象州蚕区球孢白僵菌感染家蚕获得的白僵病蚕尸体,观察不同湿度环境中白僵病蚕尸体形态的变化情况,并每隔15d进行一次分生孢子致病力测试。【结果】在25℃下的3种湿度环境（60%RH、75%RH和90%RH）中,白僵病蚕尸体在同一宿存时间内,球孢白僵菌活力与宿存湿度关系密切,在60%RH中宿存的蚕体保存较完好,60d后仍然可见淡黄白色的分生孢子,尸体质硬;随湿度增加,宿存病原活力逐渐降低。3种湿度条件下球孢白僵菌在2龄病蚕尸体中宿存30d内,对家蚕仍有很强的致病性,其半致死时间（LT50）分别为2.915、3.071和5.222d;在60%~75%RH条件下,宿存45~60d的球孢白僵菌对家蚕仍具有一定的致病力;而在90%RH条件下,宿存45d后球孢白僵菌分生孢子数量急剧下降,无法测定其致病力。【结论】球孢白僵菌在病蚕体中宿存60d内对家蚕的致死率仍然很高,因此及时清除病蚕尸体并使尸体病原性灭活,可降低白僵菌的二次感染。[Objective]Effects of host＇s environmental humidity on pathogenicity of Beauveria bassiana during white muscardine epidemic were studied to provide references for adopting proper treating and controlling measures to eliminate the influence of white muscardine on silkworm production. [ Method ]White muscardine silkworm bodies collected from Xiangzhou County of Guangxi were used to investigate their changes in different humid environment and pathogenicity every 15 days. [Result]White museardine silkworm bodies were observed at temperature of 25~C in 60%, 75% and 90% RH environment, respectively. The results showed that there was a close relationship between humidity and survival ability of Beauveda bassiana. In storage environment of 60% RH, silkworm bodies remained intact and hard with yellowish white conidium clearly seen on 60 d. The pathogen activity went down progressively at increasing humidity. Those three treatments all had strong pathogenicity of Beauveria bassiana to 2＂d-instar of silkworm during the first 30 days. Their LT~ was 2.915, 3.071 and 5.222 d, respectively. At 60%-75% RH, Beauveria bassiana still had strong toxicity to silkworm on 45-60 days, while at 90% RH, conidium number dramatically fell on the 45~ d, hence its pathogenicity could not he de- tected. [Conclusion]Within 60 days, pathogenicity rate of Beauveria bassiana to silkworm was high, therefore it was useful to reduce reinfection of Beauveria bassiana by removing the diseased silkworm body timely and inactivating body pathogenic- ity.

关 键 词：家蚕 球孢白僵菌 致病性 半致死时间 宿存 

分 类 号：S884.31[农业科学—特种经济动物饲养]