Molecularidentification And Pesticides Screeningof Four Fungal Pathogens Of Dioscorea Alata L

Purple yam (Dioscorea alata L.) is the dioscoreaceae plants list Hato Moto. It have high Nutritive value, Now,which is being planted as a kind of special organic vegetables and suitable for planting in South China large areas, but most planting areas have serious disease,,the kinds of disease is very more, so the output is not high, the tuber quality is poor. the main diseases of purple yam are the anthracnose, the Wilt, the Root nematode disease, and theLeaf spot disease, and each kind of disease is very serious and difficult to control.To Distinguish the various diseases and use True application In the field productionsoIsolating and identificating pathogens is very useful in our Field management。In this experiment by studying the yam diseases in many parts of Hainan and we found that the Purple yam are prone to fungal diseases in many earas,and the Repeated planting area areSeriouser than others,the Anthracnose andWilt are more seriouser than others,They spread very fast and It is difficult to control them, the Melasma is not serious. the anthracnose, the Wilt and theLeaf spot disease are similarand very fast, but they have different Pathogens and propagation modes.In This experiment,we use conventional tissue isolation method and single spore isolation to separated the four kinds of purple yam diseases,we Cultured and purificatied them, Constantly. finally we got four bacterias A13All A12A14, through the comparison their morphology, size, growth speeds are obviously different.They are different species。We use vitro leaves inoculation and seedling inoculation respectively to do the pathogenicity test for each kind of bacteria, the results show that each kind of bacteria are pathogenic, and have the performance with in the traits. we did the ITS analysis for the four bacterias. ITS analysis showed that: the A13is Colletotrichun dematium or Fusarium oxysporumThe results need further verification; All is Fusariumoxysporum.; A12is Ascomycota sp;A14is Aspergillusfumigatus。In This experiment we use the medicine plate bacteriostatic method to Screen for propiconazole, carbendazim, metalaxyl mancozeb, zineb, chlorothalonil, thiophanate methyl, Fenaminosulf, iprodione. The results are Fenaminosulf have the best effect for the Fusariumoxysporum;thiophanate methyl have The best control effect on Anthracnose; Carbendazim has good control effect on spotted blight; Thiophanate methyl has good control effect on black spot...