金龟子绿僵菌MaYTTR-04菌株对松墨天牛成虫的致病力

Virulence of a strain of Metarhizium anisopliae,MaYTTR-04,against adults of Monochamus alternatus

松墨天牛Monochamus alternatus Hope是重大森林植物检疫性病害———松材线虫病的主要媒介昆虫。采用跗节接种法测定金龟子绿僵菌Metarhizium anisopliae MaYTTR-04菌株对松墨天牛成虫的致病力。结果表明：在恒温条件下,松墨天牛第6天开始死亡,第18天-21天为死亡高峰期,每头成虫接种孢子量为2.3×10^6±0.2×10^6时成虫的死亡率第18天达85%,第21天达95%;时间效应指标值LT50为14.7天。室内自然变温条件下,松墨天牛第3天出现死亡,第15天-21天为死亡高峰期,每头成虫接种孢子量为2.3×10^6±0.2×10^6时的死亡率在第15天达85%,第21天达100%;时间效应指标值LT50为12.9天。林间套笼21天后,菌液处理的成虫平均死亡率为60%,僵虫率为48.9%;而通过无纺布菌条的成虫死亡率为86.7%,僵虫率为75.6%。表明MaYTTR-04菌株对松墨天牛成虫有强的致病力,且在较高变温环境温度下致病力更强。结果说明该菌株可作为生产性菌株应用于林间防治松墨天牛。

Monochamus alternatus Hope is the major insect vector transmitting pinewood nematode disease, an important quarantine disease of pine forest. The virulence of a strain of Metarhizium anisopliae, MaYTTR-04, to adult M. alternatus was assayed by using the adult-conidial-attaching method （attaching all tarsi of adult with dry conidial）. The results showed that M. alternatus began to die at 6 days post inoculation （dpi） day at constant temperature （25℃±1 ℃, RH 70% ±10%, light period 10L： 14D）. The peak of death was between 18 - 21 dpi. The mortality of this beetle was 85% at 18 dpi when applied with the amount of inoculum at 2.3 ×10^6 ±0.2 ×10^6 spores/adult, and the LT50 was 14.7 d. At room temperature （24℃ -33℃, RH 40% - 60%, natural light from north）, the adult of M. alternatus began to die at 3 dpi. The peak of death was between 15 - 21 dpi. The mortality was 85% at 15 dpi and 100% at 21 dpi when applied with the amount of inoculum at 2.3 ×10^6 ±0.2×10^6 spores/adult, and the LT50 was 12.9 d. When the adults of M. alternatus were kept in the cage in natural pine forest for 21 days, the average mortality of the adults dealt with conidia suspension was 60%, and the cadaver rate was 48.9%, while the average mortality of the adult deal with non- woven fabric strips of M. anisopliae was 86.7%, and the cadaver rate was 75.6%. It was concluded that this strain of M. anisopliae is high virulent to M. alternatus, and more virulent at higher temperature, which may serve as a productive strain of biocontrol agents and be used in forest for controlling M. alternatus.