THIOPHOSPHORIC(PHOSPHONIC) ACID ESTERS, PROCESS FOR THEIR PREPARATION AND USE AS PESTICIDES

Phosphoric (phosphonic) acid esters of the formula where R1 denotes linear or branched alkyl of up to 4 carbon atoms, R2 denotes linear or branched alkyl, alkoxy or alkylthio, each of up to 4 carbon atoms, mono- or dialkylamino of up to 4 carbon atoms in each alkyl, or phenyl, R3 denotes linear or branched alkoxy or alkylthio of up to 4 carbon atoms, amino, mono- or dialkylamino of up to 4 carbon atoms in each alkyl, alkylalkoxyalkylamino of up to 4 carbon atoms in each alkyl or alkoxyalkyl, dialkoxyalkylamino of up to 4 carbon atoms in each alkoxyalkyl, alkylalkenylamino of up to 4 carbon atoms in each alkyl or alkenyl, alkylalkynylamino of up to 4 carbon atoms in each alkyl or alkynyl, N-methyl-N-methoxyamino, N-(2-methoxyethyl)-N-(2-cyanoethyl), a 5- or 6-membered nitrogenous heterocyclic ring which may contain several nitrogen atoms and optionally oxygen as ring members, R4 denotes unsubstituted or halogen-substituted acyl of up to 4 carbon atoms, alkylsulfonyl or haloalkylsulfonyl of up to 4 carbon atoms in each alkyl or haloalkyl, the group -CO-NR5R6, R5 and R6 denoting hydrogen, linear or branched alkyl of up to 4 carbon atoms, or - but not simultaneously - phenyl, or R5 and R6 denoting, together with the nitrogen atom whose substituents they are, a 5- or 6-membered heterocyclic ring with further nitrogen atoms and an oxygen atom as ring members, or R4 denotes the group -CO-Y-R7, R7 denoting linear or branched alkyl of up to 4 carbon atoms, phenyl or benzyl, and Y denoting oxygen or sulfur, and X denotes oxygen or sulfur, which are effective against pests, especially insects, mites and ticks; pesticides containing these phosphoric (phosphonic) acid esters as active ingredients; a process for producing these active ingredients; and a process for combating pests with these active ingredients.