[Identification and prevention of root rot pathogen in model of ginseng cultivated in farmlands]

Root rot is one of the major diseases of Panax ginseng cultivated in northeastern farmlands. This study aims to identify pathogens that causing ginseng root rot disease, verify inhibiting effects of perilla crude extracts on the pathogens and present the basis for control of ginseng root rot. The species of root rot pathogens was isolated using the tissue isolation. The morphological analysis showed that the strain contained two forms of conidia, one was sickle-shaped or columnar and the other was large oval. There were obvious separations in the conidia. Based on the molecular analysis, sequence of 18s rDNA from this strain showed 100% homology with that of Fusarium oxysporum JF807402.1 by Blast. The results confirmed that F. oxysporum was the pathogenic strain for root rot of ginseng cultivated in farmlands. Inhibiting effects of perilla crude extracts were evaluated by the method of Oxford cup. The results indicated that 0.50 g•L⁻¹ of the perilla crude extract showed better sensitivity on the pathogenic strain, and its bacteriostatic diameters were 11.75 mm. The species of root rot pathogens of ginseng cultivated in farmlands was confirmed in this study. Our results presented materials for exploitation of botanical pesticide against root rot, and guaranteed the successful development of ginseng cultivated in farmland.