Research On Dendrocola Nematode-trapping Fungi

Pine wilt disease was one kind of fatal disease to pine,had been paid attention by entire world,but didn't find out a method to completely control it all the time.While it had been the hot topic at the present stage that how to control and stop the occurrence and spread of the disease with biological control method.In this article,an analysis species of the nematode-trapping fungi on infected black pine in Ninghai city of Zhejiang province was performed, determined the distribution law of nematode-trapping fungi on trees,predation effect and the interaction with other dendrocola fungi.The results as follows:In the research,7 species of nematode-trapping fungi were isolated and identified from the pine infected by pine wood nematode in Ninghai city,including 5 species of Arthrobotrys,2 species of Monacrosporium.Except A.oligospora,the other 6 were new recorded species on the tree infected by pine,including A.cladsodes,A.musiformis,A.dendroides,M. ellipsosporum,M.thaumasium and A.polycephala.The nematode-trapping fungi were abundant on the tree infected by pine wood nematode wilt disease,how to use them relieve and control the nematode had been a research emphasis.The nematode-trapping fungi weren't isolated from the healthy pine,so dendrocola nematode-trapping fungi was dependent on the pine wood nematode;the number of nematode-trapping fungi in bark was more than in xylem; there was osculation relationship between dendrocola nematode-trapping fungi and soil nematode-trapping fungi.Species and number of isolated nematode-trapping fungi in different month had a large discrepancy;it was abundant in July,September and November.The dominant species was A. oligospora in November and A.cladodes in July and September.A.cladodes is the dominant species in this place,it had extensive distribution in different part of the tree and had a high isolation rate.Predation effect was determined on 6 species of dendrocola nematode-trapping fungi isolated from the pine infected by pine wilt disease and 1 species isolated from the rhizosphere soil under 2 kind of different nutrition.As the result,every species had good predation effect, but the best predation effect was in protophase or anaphase,or maintained stable all the time.A. polycephala had the highest predation effect and the strongest adaptability;it's the best strain among the tested dendrocola nematode-trapping fungi.The predation effect of dendrocola nematode-trapping fungi were all better than soil fungi,Arthrobotrys was better than Monacrosporium.The predation effect of LPDA treatment was more stable than the LCMA.It was also found that dendrocola nematode-trapping fungi had dynamic relationship of interdependence and mutual restriction with pine wood nematode,with the time lapse,the preyed situation of pine wood nematode may have a new change.In the isolation experiment of dendrocola fungi,29 other strains were isolated and selected one strain separately from genera Trichoderma,Pestalotiopsis and Verticillium to do confrontation experiment with A.oligospora.The experimental includeed confront culture of A. oligospora with one species of dendrocola fungi and with two of dendrocola fungi.With the changing of species and number of the dendrocola fungi without nematode-trapping fungi,the result of A.oligospora was restrained or promoted was obviously different,even appeared completely opposite result.For example:A.oligospora was inhibited when A.oligospora confront cultured with Trichoderma,A.oligospora was promoted when A.oligospora, Trichoderma and Pestalotiopsis was cultured together.