Host range and mycotoxin production by Fusarium equiseti isolates originating from ginseng fields1

Fusarium equiseti is prevalent in soil and straw mulch in ginseng (Panax ginseng) fields in British Columbia and causes a reddish brown discolouration on ginseng roots. The pathogenicity of two isolates of F. equiseti from ginseng fields to other plant species belonging to different families was evaluated. Mycelial plugs and spore suspensions were used to inoculate seeds and roots in laboratory, growth room, and greenhouse experiments. Seed decay and reddish brown to black lesions were observed on hypocotyls and roots of kidney bean (Phaseolus vulgaris), bush bean (Phaseolus lunatus), broad bean (Vicia faba), chickpea (Cicer arietinum), and pea (Pisum sativum). A brownish discolouration and water-soaking symptoms developed on roots of alfalfa (Medicago sativa), canola (Brassica napus), wheat (Triticum aestivum), barley (Hordeum vulgare), and oat (Avena sativa) seedlings. Tomato (Lycopersicon esculentum), pepper (Capsicum annum), carrot (Daucus carota), and cucumber (Cucumis sativus) plants did not exhibit any visible symptoms. Diseased tissues from several affected plant species contained the mycotoxins nivalenol and (or) zearalenone at concentrations ranging from 0.3 to 11 ppm. This study shows that the host range of F. equiseti includes several members of the Leguminoseae, in addition to some cereals. The fungus may be one of the potential causes of damping-off and root rot on these plant species.