The present invention relates to a compound having the following general formula (I): ##STR1## wherein X stands for a halogen atom or a methyl radical; and R stands for an alkyl or alkoxy radical containing 3 to 6 carbon atoms provided that R represents an alkyl radical containing 3 to 6 carbon atoms when X is a methyl radical, a process for the production thereof, an agricultural composition containing the said compound as an effective component, and a method for preventing and healing the diseases of the plant and in soil using the said compound.