金龟子绿僵菌在森林土壤中的分布及对松墨天牛致病性测定

松墨天牛是重大森林植物检疫性病害——松材线虫病的主要媒介昆虫。本研究于2005年8月～2006年8月从福建、江西两省共110个林分样区(其中松林88个样区)采集土壤样品330份,采用选择性培养基分离土壤中的金龟子绿僵菌。从21个样区的26份土样中分离出的金龟子绿僵菌占采集样区的19．1％和样品的7．9％,成菌落数(CFU)500～72500CFU/g,表明金龟子绿僵菌在森林土壤中有较为广泛的分布。对分离到的9个产孢量高的菌株,采用浸渍法(1×10~7孢子/mL)接种3～4龄健康松墨天牛幼虫,采用跗节接种法接种2～15日龄健康成虫,测定其致病力。结果表明,MaYTTR-03、MaYTTR-04菌株对松墨天牛幼虫和成虫均有较高致病力,表现出良好的生防潜力。

The investigation of Metarhizium anisopliae in forest soil in Fujian and Jiangxi provinces and pathogenicity against Monochamus alternatus

Monochamus alternatus is the main vector of pinewood nematode, a critical plant quarantine organism. Three hundred and thirty soil samples were collected from 110 forest fields (of which 88 were pine wood fields) distributed over 40 counties in Fujian and Jiangxi province from August 2005 to September 2006. Metarhizium anisopliae was detected in 26 soil samples from 21 forest fields (of which 16 were pine wood fields) by selective medium, which accounted for 7.9% of the samples and 19.1% of the fields. Colony Forming Units (CFU) of M. anisopliae in the soils ranged from 500 to 72500CFU/g, indicating a wide distribution of this fungus. The pathogenicity of 9 well sporulating isolates against M. alternatus was evaluated by using adult-conidial attaching method and larva dip method. MaYTTR-03 and MaYTTR-04 have showed high virulence to M. alternatus and the mortality in 21d after inoculation was 80.0% and 76.0% for larvae and 83.4% and 88.9% for adults respectively at inoculation of 1.2×10⁶ ± 2.0×10⁵ and 1.5×10⁶ ± 5.0×10⁵ conidia/individual, indicating their high potential for management of M. alternatus.