The Study Of Isolation And Identification Of Tea Anthracnose Pathogens And Prevention Technology

Tea is an important economic crop in our country,Colletotrichum which cause serious threat to the development of tea industry will directly affect the yield and quality of tea,and have an increased trend in recent years.The objectives of work were to figure out the pathogen of anthracnose and its biological characteristics.The toxicity of nine kinds of fungicides were tested in the indoor experiments so that effective fungicides could be selected from existing fungicides and provided scientific basis for the disease control.The bio-fertilizer Bacillus amyloliquefaciens B2was used for tea plant cultivation.The endophytic bacteria were isolated from the fertilized tea leaves,then were screened and cultured for the experiment of antagonistic effect to pathogenic fungi of anthracnose.The main results were as follows:1.6 strains were isolated and purified from anthracnose leaves of tea in Ningde,Zhouning,Longyan in Fujian province,then inoculate the health and re-separate.With the onset of natural field show similar symptoms,the typical symptoms of leaf tissue separation again.It has been proved that the isolate was the pathogen of anthracnose by the method of Koch s Rule.2.Cultured in PDA medium for 7days,the colony come into being a color of orange grease on the central bulge,the mycelia were closely and villus in the center of gray,the edge is white.The medium was concentric structure with the melanin on the reverse side.The morphological characterizations were performed by observing the fruiting bodies,which were oblong,oval,colorless and the black grain on the surface.On the basis of traditional morphological classification and morphological identification,the pathogen were identified as anthracnose.To confirm the morphological diagnosis,the genomic DNA was extracted from mycelia grown on PDA plates following the procedure described by DNA extraction kit,then conducted DNA quantification and purity analysis.PCR products obtained using primers ITS,?-Tub,LSU,GS and CglNT,respectively.The sequences were compared with those in Genebank.Furthermore the analyses confirmed the results of the morphological characterization,these strains were Colletotrichum Corda.3.In order to screen effective fungicides to control anthracnose pathogens,the toxicity measurement against its pathogen by inhibition of mycelium growth,calculated the toxicity regression equations and the effective inhibition of the concentration.It was found that 40%prochloraz,50%azoxystrobin,40%cyprodinil could significantly inhibit mycelium growth,while 80%carbendazim was the worst.4.The results showed that the number of endophytic bacteria in fertilized tea leaves were significantly increased,the antagonistic ability of the fertilized leaves against pathogenic fungi of anthracnose is equal to the Bacillus amyloliquefaciens B2 stains.PCR amplification of 16S rRNA gene,sequencing and alignment,and phylogenetic analysis for screened endophytic Bacillus strains and B2 were carried out,the result of 99.93%similarity between the sequences,and the morphological identification,ensured that B2 was propagated successfully in tea plant.Additionally,the fertilizer application has not showed significant effect on the morphological development of tea plant.5.We discussed the possibility of carrying out ecological control diseases in tea garden without using chemical pesticide,adopting a nested manner by planting variety trees and crops to enhance the ecological self-regulating ability of tea plantation and reduce diseases.It is necessary for developing ecological tea garden because of its good nature environment and promoting to enhance the tea quality.At last we can establish tea industry in a new model of green development,enhance the tea brand of"Fresh Fujian and Green Agriculture".