Screening And Preliminary Application Of Entomopathogenic Nematodes For Controlling Fungus Gnats On Edible Fungi

China is a major country of edible fungi production.In recent years,with the further expansion of the planting scale of many edible fungi,the damage of fungus gnats to edible fungi has become more and more severe.Lycoriella pleuroti and Phyxia scabiei are important pests that harm many edible fungi.The application of entomopathogenic nematodes to control the larvae of L.pleuroti and P.scabiei has good prospect for the sake of safe edible fungi production,and the key to safe edible fungi production is to choose appropriate species of entomopathogenic nematodes.In this paper,the pathogenicity of five entomopathogenic nematodes(Heterorhabditis bacteriophora H06,H.indica LN2,Steinernema feltiae SN,S.carpocapsae All and S.longicaudum X-7 on L.pleuroti and P.scabiei.On the basis of pathogenicity test,the effects of six different types of insecticides on the infectivity of selected dominant entomopathogenic nematodes and effectiveness of mixture of insecticides and dominant entomopathogenic nematodes for L.pleuroti were determined.The control effectiveness of dominant entomopathogenic nematodes for L.pleuroti in the mushroom house was studied.The S.feltiae SN was the most resistant to low temperature among the five entomopathogenic nematodes and had good infection effect on the larvae of L.pleuroti and P.scabiei at 15～30℃.At 25～30℃,the infection effects of H.bacteriophora H06 and S.feltiae SN on the larvae of L.pleuroti were the best,while the infection effectiveness of S.feltiae SN and S.carpocapsae All for the larvae of P.scabiei were the best.The infection rates of the selected dominant nematodes to the larvae of L.pleuroti and P.scabiei were higher with higher temperature rise within a certain temperature range.The control effectiveness of H.bacteriophora H06 for the L.pleuroti larvae and that of S.feltiae SN for the P.scabiei larvae were quite significant when the ratio of fungus gnat number to nematode number is more than1:200.The control effectiveness of S.feltiae SN for the larvae of L.pleuroti were the bast when the ratio of fungus gnat number to nematode number is more than 1:400.When S.carpocapsae All was used to control the P.scabiei larvae and the ratio of fungus gnat number to nematode number is at least 1:100,the effectiveness is obvious.The S.feltiae SN was used to control the L.pleuroti larvae in mushroom house,at 21～28d the mortality rate was over80% and the decline rate of the L.pleuroti larvae was obvious when the nematode concentration was 800:1 and 400:1.At 28～35d,although the mortality of L.pleuroti is lower,but the control effectiveness still was better.Among six kinds of insecticides（ethyl spinosad,chlorfenapyr,cyfluthrin,matrine,chlorobenzuron and cyantraniliprole）,matrine had a slightly higher mortality rate for entomopathogenic nematodes,while the other five insecticides had no adverse effect on the infection and survival of nematodes.The mixture of three concentrations of ethyl spinosad with cyfluthrin 2RC（2× recommended concentration）and S.feltiae SN can significantly increase the infection rate of L.pleuroti,which is better than that of nematodes alone.The mixture of chlorfenapyr RC,1/2RC with S.feltiae SN can significantly increase its infection rate to L.pleuroti,which is significantly higher than that of nematodes alone.