Method of controlling fungal diseases in plants and Compositions effective therefor are shown. The method comprises the steps of applying an effective amount of a substituted derivative of 1,1,-dichloroalkene-1 of the general formulaR--X--(CH.sub.2).sub.n --CH.dbd.CCl.sub.2In this generalized formula R is an alkyl group having 1 to 12 carbon atoms, a phenyl group, a di-chloro-phenyl group, a methyl-phenyl group, a nitro-phenyl group, a benzyl group, a chloro-benzyl group, a di-chloro-benzyl group, a methyl-benzyl group, a phenethyl group or a benzothiazolyl group; X is sulfur, a sulfinyl group or a sulfonyl group; and n is an integer of 3,5, and 7.