Study On The Action Clonostachys Rosea With Four Tree And Fruit Of Stems Bio-control Pathogens

The diseases on timber trees and fruit trees caused by Botryosphaeria dothidea,Valsa mali,Valsa sordida,Fusarium oxysporum are serious biological disasters.At present,the chemical control method is adopted widely,while the effect of control is not stable and the environment pollution is serious.Biological control is an effective and enduring method to control the disease.Clonostachys rosea be regarded as one of the most important biological control agents with the advantage of rapid growth,large amount of spore production,wide host range,strong parasitic ability,varietal antagonistic mechanism.It has important significance to carry out the control effect of Clonostachys rosea on stem diseases of timber trees and fruit trees.In this study,one strain of Clonostachys rosea was isolated from disease branch of apple tree,the strain was cultured and identified.The biological control ability of the strain was identified by further experiments,all of this has important research significance.On the basis of study in morphology and growth characteristics of Clonostachys rosea,we focus on exploring the effect and mechanism of Clonostachys rosea with different pathogen.The results of the study are as follows:Colony morphology show that:in early stage colony of Clonostachys rosea was white,the edge is neat,hyphae creeping,loose,the aerial hyphae is not developed and then colony becomes pink.There is little water overflow on the surface of the colony,and the bottom of the colony produce light red pigment.Through the cultivation of Clonostachys rosea,we found Clonostachys rosea produced a large number of conidia.Measure of growth characteristics of continuous multiple generations,the growth characteristics of Clonstachys rosea is relatively stable and will not be degraded with continuous culture.We come to the conclusion that Clonostachys rosea is a kind of stable biological control agent.ITS sequence determination showed that the strain is similar with the strain of Clonostachys rosea submitted in GenBank,homology reached 100%.The study identified the strain as Deuteromycota,hyphomycetes,moniliales Moniliaceae,Gliocladium,Clonostachys rosea.Through the determination of Clonostachys rosea biological control effect we found:the area of scabs on the appples which inoculate Clonostachys rosea and Botryosphaeria dothidea at the same time is smaller than the scabs on the apples which only inoculate Botryosphaeria dothidea;the area of scabs on the apples which inoculate Clonostachys rosea previously and then inoculate Botryosphaeria dothidea is minimum.There is no scabs on apple fruit and apple branch which only inoculate Clonostachys rosea,This shows that Clonostachys rosea does not have pathogenicity.But the inhibition rate that Clonostachys rosea with Botryosphaeria dothidea,Valsa mali,Valsa sordida and Fusarium oxysporum was more than 60%.Plate stand facing culture and microscopic observation of Clonostachys rosea with Botryosphaeria dothidea,Valsa mali,Valsa sordida and Fusarium oxysporum showed that hyphae fusion was emerged in areas where the confrontation colony touched.Hyphae of Clonostachys rosea formed a hyphae ring or wound on the hyphae of the pathogen directly,the structure of attachment was formed and then penetrate into the internal hyphae,the hyphae of pathogen degradation,resulting in discoloration,wilting and death.The above results show that Clonostachys rosea is a stable,parasitic ability of biological control.This is the first time that biological control agent be found from branch of timber trees and fruit trees.It is also proved that Clonostachys rosea has good development and application value.