A method of protecting plants and seeds thereof which are susceptible to attack by microorganisms. To the plant or seed is applied a compound having the formula (see fig.I) wherein R and R' are independently selected from hydrogen and alkyl of 1 to 4 carbon atoms; and R" is a moiety selected from the group consisting of (a) hydrogen, (b) a halogen atom selected from the group consisting of F, C1, Br and I, and (c) a nitro group or the hydrochloride salt of the compound. The method disclosed is especially useful for protecting ornamental plants, vegetable plants and cereal crop plants and seeds thereof which are susceptible to attack by microorganisms. A composition containing the compound of formula I for use in protecting plants which are susceptible to attack by microorganism is also provided.