金龟子绿僵菌对椰心叶甲的致病力

采用喷菌法接菌,测定5株金龟子绿僵菌对不同龄期椰心叶甲的致病力。结果表明:浓度为(1±0.5)×10~7孢子·mL~(-1)的孢子悬液接菌10 d后,各绿僵菌菌株对该虫不同发育阶段均有一定致病力。其中,以Ma1775菌株对椰心叶甲致病力最强,成虫校正死亡率和僵虫率分别为(67.96±3.66)%和(60.59±1.31)%,LT_(50)为(7.11±0.52)d;5龄幼虫校正死亡率和僵虫率分别为(78.53±2.73)%和(73.55±3.22)%,LT_(50)为(5.77±0.38)d;4龄幼虫校正死亡率和僵虫率分别为(82.59±2.48)%和(77.86±3.44)%,LT_(50)为(5.80±0.14)d;2~3龄幼虫校正死亡率和僵虫率分别为(73.46±4.60)%和(69.50±3.87)%,LT_(50)为(6.49±0.12)d。Ma1775菌株对该虫各发育阶段6 d的LC50分别为:3.52×10~8、7.13×10~7、2.48×10~7、7.69×10~7孢子·mL~(-1)。时间-剂量-死亡率(time-dose-mortality,TDM)模型分析结果表明椰心叶甲各发育阶段幼虫死亡高峰期均为3~7 d。因此,Ma1775菌株在椰心叶甲生物防治中有较大的应用潜力。

Pathogenicity of Metarhizium anisopliae against Brontispa longissima

The virulence of 5 Metarhizium anisopliae strains against Brontispa longissima in different development stages were determined by spraying.The results showed that various strains of M.anisopliae had certain virulence against B.longissima after inoculation with (1±0.5)x107 spore·mL-1 for 10 d.Compared various strains,Ma1775 strain exhibited the most effective virulence against B.longissima.Mter treatment,the Ma1775 strain caused a cumulative corrected morality of (67.96±3.66)％,the cadaver rate of (60.59±1.31)％ and the median lethal time (LT50) of (7.11±0.52) d in adults.For 5 instar larvae,the corrected mortality and cadaver rate were (78.53±2.73)％ and (73.55±3.22)％,with LT50(5.77±0.38) d.The corrected mortality and cadaver rate were (82.59±2.48)％ and (77.86±3.44)％,and LT50 was (5.80±0.14) d for 4 instar larvae.The corrected mortality and cadaver rate were (73.46±4.60)％ and (69.50±3.87)％ for 2～3 instar larvae,with LT50(6.49±0.12) d.The median lethal concentration (LC5o) of Ma1775 strain at each development stage in 6 d were 3.52×10s,7.13×107,2.48× 107,7.69×107 spore· mL-1,respectively.By employing a time-dose-mortality model to estimate parameters of time and dose,the Ma1775 strain had a high lethal effect on B.longissima during 3～7 d after treatment.Thus,the Ma1775 strain has been proved to be a great potential application in biological control to B.longissima.