Combating pests with N-phosphonylcarbonyl-carbamates

An N-phosphonylcarbonyl-N-methylcarbamic acid ester of the formula ##STR30## in which R.sup.1 and R.sup.2 can be identical or different and each represents straight-chain or branched alkyl with 1-8 C atoms, alkenyl with 3-6 C atoms or alkynyl with 3-6 C atoms, it being possible for R.sup.1 and R.sup.2 optionally to be substituted by 1-3 halogen atoms, and

• R.sup.3 represents alkyl with 1-4 C atoms, phenyl, naphthyl, benzodioxolanyl dihydrobenzofuranyl or indanyl, it being possible for any of these radicals to carry one or more substituents selected from alkyl, alkenyl, alkynyl, alkoxy, alkenoxy, alkynoxy, alkylmercapto, alkenylmercapto, alkynylmercapto and dialkylamino with in each case up to 4 C atoms, and trihalogenomethyl, halogen, nitro, cyano, cycloalkyl, formamidino, dioxanyl and dioxolanyl, or
• R.sup.3 represents the radical of the formula ##STR31## in which R.sup.4 and R.sup.5 can be identical or different and each represents alkyl, alkoxy or alkylthio, with in each case 1 to 4 carbon atoms, cyano, alkoxycarbonyl or alkylthioalkyl with 2 to 4 carbon atoms, dialkylcarbamoyl or dialkoxyphosphonyl, with 1 to 4 carbon atoms per alkyl group, or triazolyl, or
• R.sup.4 and R.sup.5, together with the C atom to which they are bonded, form a dithiolane, dithiane, oxythiolane or oxathiane ring which is optionally substituted by methyl or phenyl.