不同温湿度下球孢白僵菌对小猿叶甲的致病力(英文)

Effect of temperature and humidity on the virulence of beetle-derived Beauveria bassiana (Balsamo) Vuillemin (Deuteromycetes: Moniliales) against the daikon leaf beetle, Phaedon brassicae Baly (Coleoptera: Chrysomelidae)

本文在室内研究了分离自小猿叶甲的一株球孢白僵菌(SCAU-BB01D)在不同温度和湿度条件下对小猿叶甲成虫和2龄幼虫的致病力.结果显示温度和相对湿度对白僵菌的致病力有显著影响.在17℃和29℃,小猿叶甲成虫和2龄幼虫的死亡率显著低于其他温度;在23℃下,成虫接菌后第14天的累计死亡率达到最高为95.60%;在23℃和26℃下,2龄幼虫接菌后第10天达到最高累计死亡率96%.随着相对湿度的提高,球孢白僵菌对小猿叶甲的致病力显著增加,当相对湿度从50%增加至100%时,成虫第14天的累计死亡率从55.70%增加到88.80%,2龄幼虫第10天的累计死亡率从62.00%增加到96.00%.机率值分析结果表明,在17、20、23、26和29℃温度下,白僵菌对小猿叶甲成虫和2龄幼虫的LT50分别为13.63、10.27、8.05、8.87、12 41天和6.06、5.72、4.90、4.86、6.73天.随着相对湿度的升高,球孢白僵菌对小猿叶甲的致死中时(LT50)呈缩短的趋势,当相对湿度为50%、60%、70%、80%、90%、100%时,成虫和2龄幼虫的LT50分别为12.97、10.97、10.13、9.79、9 14、8.29天和7.68、6.92、5.76、5.57、5.48、4 82天.由实验结果可以得知,23～26℃是球孢白僵菌感染小猿叶甲最适宜的温度范围,环境湿度越高越有利于病原菌侵染,当相对湿度大于90%时,最有利于球孢白僵菌对小猿叶甲的感染.

In this study, the effect of temperature and humidity on the virulence of a Beauveria bassiana isolate, SCAU-BB01D, to Phaedon brassicae, a serious insect pest of cruciferous vegetables in South China, was studied in the laboratory. The mortality of P. brassicae was significant lower at temperature of 17℃ and 29℃ than at other temperatures. At temperature of 23℃ , the mortality of adult on the 14th day after treatment reached its highest, 95.60%. For 2nd instar larvae the highest mortality （96.00%） was obtained at both 23℃ and 26℃ on the 10th day after treatment. The pathogenicity of B. bassiana to P. brassicae was enhanced as relative humidity increased. When relative humidity （RH） was increased from 50% to 100%, adult mortality 14 days after treatment was enhanced from 55.70% to 88.80% and 2nd instar larvae mortality 10 days after treatment was enhanced from 62.00% to 96.00% . At 17, 20, 23, 26, and 29℃ , the LT50 values were 13.63, 10.27, 8.05, 8.87 and 12.41 days for adults, and 6.06, 5.72, 4.90, 4.86 and 6.73 days for 2nd instar larvae, respectively. LT50 values at RH of 50%, 60%, 70%, 80%, 90% and 100% were 12.97, 10.97, 10.13, 9.79, 9.14, 8.29 for adults and 7.68, 6.92, 5.76, 5.57, 5.48, and 4.82 days for 2nd instar larvae, respectively. Therefore, temperatures between 23-26℃ and RH higher than 80% were the most suitable conditions for promoting infection of B. bassiana to P. brassicae.