Isolation And Identification Of Pathogen Of "Black Head Disease" Of Pueraria Thomsonii Benth And The Examination Of Biological Characteristics

Pueraria thomsonii Benth is a vine belonging to Pueraria of the pulse family,which can be eaten as well as used for medicine.Not only has good nutrition and health care value,but also has various medicinal values and biological activity functions.And it plays an important role in the market of Chinese medicine.In recent years,with the continuous expansion of the planting area of P.thomsonii Benth,the occurrence of Black head disease of P.thomsonii Benth has become more and more serious,which has seriously restricted the vigorous development of P.thomsonii Benth industry and caused great economic losses.In oeder to identify the pathogenic species of Black head disease of P.thomsonii Benth,and To explore the influencing factors on the growth of the pathogens,and To analyze the optimum growth conditions for the pathogens,and to select highly efficient Trichoderma spp.strains for root rot of P.thomsonii Benth.In this research,through pathogens isolation and identification root rot of P.thomsonii Benth,biological characteristics,select highly effective Trichoderma Strains,the main results follows:The research regard Infected tissue of P.thomsonii Benth as target.The moisture-preserving culture method used to separate and identify the different diseased parts of Pueraria thomsonii Benth and determine the pathogenicity of inoculation.The results showed that 87 strains were isolated,According to morphological and molecular biological identification,51 strains belong to 5 species of Fusarium sp.Including Fusarium incarnatum has 17 strains、Fusarium oxysporum has 14 strains、Fusarium incarnatum has 14 strains、Fusarium solani has8 strains、Fusarium commune has 6 strain,and there are 26 strains not identified.So,separation frequency of Fusarium sp.is 88.51%.through Koch’s postulation,the main pathogens were F.proliferatum,F.oxysporum and F.commune.Study the biological characteristics of three pathogens,1)The results showed that the optimal culture medium for F.proliferatum is Czapek’s Agar media,the optimal p H of mycelia growth and sporulation was 11 and 8,the optimal carbon source for mycelia growth and sporulation were glucose and sucrose,the optimal nitrogen source for mycelia growth and sporulation is nitrate and peptone.the optimal microelements for mycelia growth and sporulation were Fe SO4 and Zn SO4,the optimal light condition for mycelia growth and sporulation was 12 h alternating light and dark,the optimal temperature for mycelia growth and sporulation was 25℃.2)The optimal culture medium for F.oxysporum of mycelia growth and sporulation were LD and PSA media,the optimal p H was 6,the optimal carbon source for mycelia growth and sporulation were glucose and fructose,the optimal nitrogen source was peptone,the optimal microelements for mycelia growth and sporulation were Mn SO4 and Zn SO4,the optimal light condition for mycelia growth and sporulation was 24 h dark,the optimal temperature for mycelia growth and sporulation was 28℃.3)The optimal medium for F.commune of mycelia growth and sporulation were LD and Czapek’s Agar medium,the optimal p H of mycelia growth and sporulation were 6 and 4,the optimal carbon source for mycelia growth and sporulation were soluble starch and maltose,the optimal nitrogen source for mycelia growth and sporulation were sodium nitrate and nitrate,the optimal microelements for mycelia growth and sporulation were Cu SO4 and Na2 Mo O4,the optimal light condition for mycelia growth and sporulation were 24 h light and 24 h dark,the optimal temperature for mycelia growth and sporulation were 28℃ and 25℃.Antagonistic effect strain was screened in 12 Trichodrema strains by dually culture method。The result showed that 3 strains were screened that it against F.proliferatum,it contains T2,T7 and T10 in sequence with antibacterial rates of 71.56%,74.92%,and 69.42% respectively.There are 3 strains were screened that it against F.oxysporum,it contains T1,T7,and T10 in sequence with antibacterial rates of 79.54%,82.79%and77.06% respectively.There are 3 strains were screened that it against F.commune,it contains T2,T3 and T9 in sequence with antibacterial rates of 65.63%,64.69% and 64.69% respectively.The result showed that the volatile metabolites of T10 has a better antibacterial effect on F.proliferatum with antibacterial rate of 45.12%.The volatile metabolites of T10 has a better antibacterial effect on F.oxysporum with antibacterial rate of 50.44%.