Evaluation of N-(1-alkoxy-2,2,2-trichloroethyl)-2-hydroxybenzamides for Clubroot Control in Chinese Cabbage. Kaoru Ohmori, Ageo Research Laboratory, Agrochemicals Division, Fine Chemicals Group, Nippon Kayaku Co., Ltd., Koshikiya, Ageo-Shi, Saitama-Ken 362, Japan. Taizo Nakagawa, and Kengo Koike, Ageo Research Laboratory, Agrochemicals Division, Fine Chemicals Group, Nippon Kayaku Co., Ltd., Koshikiya, Ageo-Shi, Saitama-Ken 362, Japan. Plant Dis. 70:51-53. Accepted for publication 19 June 1985. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1986. DOI: 10.1094/PD-70-51.

Ten N-(1-alkoxy-2,2,2-trichloroethyl)-2-hydroxybenzamides were tested in the greenhouse against Plasmodiophora brassicae, causal agent of clubroot of Chinese cabbage. C₄, C₅, and C₆ derivatives of the alkoxy group gave better clubroot control than the standard PCNB. The most effective derivative, N-(1-butoxy-2,2,2-trichloroethyl)-2-hydroxybenzamide (trichlamide), was field-tested. Clubroot control on Chinese cabbage with preplant broadcast soil treatment of trichlamide at 30 kg a.i./ha was equal to that obtained with standard PCNB treatment (50 kg a.i./ha). Yield increase was associated with decrease in disease severity.