Evaluation of the efficacy of fumigants allyl isothiocyanate and dimethyl disulfide against Panax notoginseng root rot caused by Fusarium solani

Fusarium root rot caused by Fusarium solani severely damages the roots of Panax notoginseng (ginseng) seedlings eventually leading in most cases to the total loss of this valuable crop. Soil fumigants are generally better at controlling soil-borne diseases such as F. solani than fungicides which provide unacceptable control. We tested the efficacy of two fumigants allyl isothiocyanate (AITC) and dimethyl disulfide (DMDS) against F. solani in the laboratory. AITC inhibited F. solani mycelial growth completely at a concentration of 1.2 μg/L and significantly reduced CO 2 emissions of F. solani . Ultrastructural studies showed that AITC disrupted the cell membrane of F. solani by causing plasmolysis and plasma leakage. AITC had multiple modes of action affecting F. solani cell respiration, plasmolysis and cell membrane function. However, the inhibitory effect of DMDS was slightly less than AITC which was mostly ineffective against F. solani . In all, AITC but not DMDS effectively controlled F. solani in ginseng production and could therefore be recommended as controls for this disease as a component of an integrated pest management program.