长枝木霉对南方根结线虫致死和寄生作用的显微观察及测定

摘要

对不同时期长枝木霉(Trichoderma longibrachiatum)分生孢子悬浮液对南方根结线虫(Meloidogyne incognita)2龄幼虫的致死和寄生作用过程进行了显微观察和室内测定.显微观察结果表明,侵染初期长枝木霉分生孢子吸附或寄生在虫体的表面,并且分生孢子萌发产生大量的菌丝穿透虫体体壁.侵染后期被分生孢子寄生的虫体开始出现畸形,且寄生的部位出现缢缩和溶解,甚至有的虫体完全溶解.室内测定结果表明,不同浓度长枝木霉分生孢子悬浮液对2龄幼虫具有明显的致死和寄生作用,并且不同浓度长枝木霉分生孢子悬浮液之间存在显著的差异.第14天浓度为1.5×107个/mL的长枝木霉分生孢子悬浮液对2龄幼虫的寄生率为87.33％,以及72 h后2龄幼虫的死亡率和校正死亡率分别为90.00％和88.81％.%The lethal and parasitic effects of the conidial suspension of Trichoderma longibrachiatum on the second-stage juveniles of Meloidogyne incognita were studied in vitro and observed under microscopic conditions.Microscopic observation results showed that the conidial suspension of T.longibrachiatum adsorbed or parasitized the surface of second-stage juveniles,germinated a large number of hyphae and penetrated the integument at the initial stage.The parasitized nematodes were later become deformed and begun to dissolve,and some second-stage juveniles were even completely dissolved.In vitro studies showed that different concentrations (1.5 × 105-1.5 ×107 cfu/mL) of T.longibrachiatum had strong lethal and parasitic effects on the second-stage juveniles of M.incognita,and there was significant difference between different concentrations of T.longibrachiatum.The parasitic rate of the second stage juveniles was 87.33％ at 14 d,and the mortality and corrected mortality of the secondstage juveniles were 90.00％ and 88.81％,respectively,after 72 hours,when treated with 1.5 × 107 cfu/mL T.longibrachiatum.