Isolation,Identificationand Fungicides Screening For Pathogen Causing Panax Notoginseng Root Rot

In recent years, the root rot of panax notoginseng is rising with the industrialization andlarge-scale production, It has been one of impotant limitations of panax notoginsengproduction. In this research, biological characteristics, chemical control of pathogen wasidentified and studied from panax notoginseng Root Rot and rhizosphere soil.First of all, the author isolated90fungals from the growing areas of panax notoginsengroot rot From Yunnan wenshan and rhizosphere soil around it, Based on colony morphology,preliminary identification and Koch’s postulates, which can be divided into six categories:Fusarium oxysporum, Fusarium oxysporum, Alternaria alternaria, Penicillium, Aspergillusand Trichoderma spp. The separation frequency of six pathogens are were26.67%,24.44%,20.00%,24.44%,8.89%and7.78%. To further identify the taxonomic status of pathogenicbacteria. The18S rDNA gene sequence of filamentous fungi was amplified by PCR usingfungal universal primers NS1and NS6sequence analysis.The results of the biological studies on Fusarium solani, Fusarium oxysporum andAlternaria alternaria showed that25℃and pH7.0is the optimum condition for Fusariumsolani, Peptone and beef extract has the obvious effect on the growth of Fusarium solani,1.5g/L K ion can promot the growth of Fusarium solani.25℃is the optimum condition forFusarium oxysporum, peptone, yeast extract, beef extract can promot the growth of fusariumoxysporum as Nitrogen source,1.5g/L K ions is the optimum condition for Fusariumoxysporum. Alternaria alternaria can grow in15~40℃，growing faster with the temperaturegrowing.Using the toxicity of fifteen fungicides were determined by testing the colony growth.conidial germination rate and colony growth. The test showed that250timesThiophanate-Methyl,700times mancozeb,3000times difenoconazole,1000times the greenwith50billion living bacterium,250times Carbendazim,600times Anti-rot&cancer,1000times Polyoxin B has good effect on Fusarium oxysporum.250times Thiophanate-Methyl,25%carbendazim, root health,600times Lvdu agents with100billion living bacterium hasgood control on Fusarium solani,250times Thiophanate-Methyl,700times mancozeb,500 times procymidone,1000times the green with50billion living bacterium,3000timesdifenoconazole has effective control Alternaria tenuis.Field text of prevention for panax notoginseng root rot shows that600timesAnti-rot&cancer,250times Thiophanate-Methyl,600times the green with100billion livingbacterium can effective control panax notoginseng root rot caused by Fusarium solani, thehealth index is86.67,86.67,80.1000times the green with50billion living bacterium,600times Anti-rot&cancer,250times Thiophanate-Methyl can effective control panaxnotoginseng root rot caused by fusarium oxysporum.500times procymidone,250timesThiophanate-Methyl, root rot prevention effect is good,70%methyl sulfur bacteria spirit250times,50%pythium can effective control panax notoginseng root rot caused by Alternariatenuis.