Henan Province Poplar Canker Pathogen Identification And Biological Characteristics

Poplar canker is one of the most serious hazards in poplar which poplar seedlings,saplings and trees are all infringed, and seedlings, saplings suffer the most. Poplarcanker which is very severe in henan province in recent years has been a obstaclefactor in the development of poplar industry. Reports on the pathogens of poplarcanker are not very consistent and there has been more than ten kinds in the reports.Because the difference between the poplar canker bacteria morphology and the relatedplant pathogen morphology are not significance, especially in the asexual stage, it isdifficult to make an accurate identification only depending on pathogen morphology.In this study, poplar canker standard sample collected from18cities in henanprovince and employing the method of separation and cultivation, the kinds ofpoplar canker pathogens are appraised by morphology and DNA sequence. Accordingto the results, the kinds of poplar canker and strains constituent can be identified inhenan province, in addition, a research is made on biological characteristics of poplarcanker in henan province. The aim of this study is to provide the basis for monitoringand controlling poplar canker. The results are as follows:1.18poplar canker strains are separated from the test which all can creat typicalcanker symptoms, and these strains can be devided into3groups according tocolonies characteristics. Only asexual generation is appeared in the culturing course,and the morphology and characteristic is very similar to the Dothiorella gregaria Sacc.and Fusicoccum aesculi Corda. Described in the literature.2. ITS and β-tubulin gene sequences of the18strains from the test, comparisionwith the sequence registered on NCBI, the conclusion is reached that the strains areBotryosphaeria dothidea (Moug: Fr) Ces. Et de Not. Combined with morphology andcharacteristics and literature, the result is made that Asexual type of poplar canker is F.aesculi. 3. Based on the ITS and β-tubulin gene sequences of the18strains from the test,an application is made to establish phylogenetic tree with the means of Neighbor-Joining (NJ) and Maximum Parsimony (MP). Analyzing the relationship of the strains,it is found that these strains can be divided into several subgroups.4. the study on biological characteristics of the poplar canker in henan provinceindicate that optimum mycelial growth temperature of fungi is25℃; peptone is thebest nitrogen source in the tested carbon source, sucrose followed by; the optimum pHvalue is6and it can also grow mormally between4and11;80%ethylicin EC,430g/ltebuconazole SC,15%bismerthiazol WP is most sensitive to the poplar cankerfungi in the16kinds of fungicides.According to the DNA sequence analysis, the conclusion is made that the sexualtype of poplar canker fungi in henan province named B. dothidea and the asexualgenerations type named F. aesculi.80%Ethylicin EC,430g/L tebuconazole SC,15%bismerthiazol WP can be used in prevention of poplar canker.