Efficacy of soil fumigants for control of Verticillium wilt of potatoes

Soil fumigation with materials containing methyl isothiocyanate, 1, 3-dichloropropene, or trichloronitromethane, alone or in combination, delayed “early maturity disease” symptoms caused byVerticillium dahliae Kleb, in potatoes and increased yields. Soil fumigation increased the crop value as much as $818 per acre, depending on the material and rate, used when potatoes were grown for two consecutive years following fumigation. With the exception of trichloronitromethane, fall fumigation was as effective or more effective than spring fumigation.