金龟子绿僵菌对椰心叶甲的致病力

Pathogenicity of Metarhizium anisopliae against Brontispa longissima

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。

The virulence of 5 Me ta rhizium, ani sopl iae strains against B r o n t i sp a lo n g i s s ima in different development stages were determined by spraying. The results showed that various strains of M. a n i s o p l ia e had certain virulence against B . lo n g i s s im a after inoculation ＂with （ 1 ±0.5）x107 spore.inL 1 for 10 d. Compared various strains, Ma1775 strain exhibited the most effective virulence against B. longissima. After treatment, the Ma1775 strain caused a cumulative corrected mortality 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 Lr50（5.77±0.38） d. The corrected mortality and cadaver rate were （82.59±2.48） % and （77.86±3.44） %, and ir50 ＂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 ir50（6.49±0.12） d. The median lethal concentration （iC50） of Ma1775 strain at each development stage in 6 d were 3.52 ×105, 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 .