Method of controlling mollusc pest

A method of controlling mollusc which comprises subjecting them to a molluscicidally effective amount of a compound of the formula:

• R1 ? ##STR5## wherein:
• R' is alkyl having from 1 to 4 carbon atoms;
• R.sub.2 is alkyl, alkylthio, alkylsulfinyl, alkylsulfonyl, alkoxy, alkanoyl or alkoxycarbonyl, all of which may be unsubstituted or aliphatically substituted in any combination with one or more cyano, nitro, alkylthio, alkylsulfinyl, alkylsulfonyl, alkoxy or phenyl;
• or R.sub.2 is R.sub.4 R.sub.5 --NCO or R.sub.6 CON(R.sub.4)--groups, wherein:
• R.sub.4 and R.sub.5 are individually hydrogen or alkyl;
• R.sub.6 is hydrogen, alkyl or alkoxy;
• R.sub.3 is hydrogen, alkyl, alkylthio, alkylsulfinyl, alkylsulfonyl or cyano;
• with the provisos that:
• A. the total number of carbon atoms in R.sub.2 and R.sub.3 together may not exceed eight;
• and
• B. when R.sub.2 is alkyl substituted with alkylthio, R.sub.3 is cyano, alkyl, and alkylthio.