Abstract: Novel compounds corresponding to the formula ##STR1## wherein R is H or an alkyl group having from 1 to about 7 carbon atoms. Their method of use in the control and kill of bacteria and fungi, and compositions containing the compounds as active ingredients are claimed.

Abstract: O-Alkyl-S-[1,6-dihydro-6-oxo-pyridazin(1)ylmethyl]-(thiono)-(di)-thiolphosp horic(phosphonic) acid esters of the formula ##STR1## in which R.sub.1 is alkyl or alkoxyalkyl with 1 to 6 carbon atoms per alkyl chain,R.sub.2 is alkyl, alkylmercapto, alkylamino or alkenylamino with up to 6 carbon atoms per aliphatic chain, amino or phenyl, andR.sub.3 is alkoxy, cyanoalkoxy, carbalkoxy-alkoxy, alkenyloxy, alkynyloxy, alkanoyloxy, dialkylcarbamoyloxy or alkylsulfonyloxy with up to 5 carbon atoms in each aliphatic chain, halogen, hydroxyl, or a (thiono) (thiol)-phosphoric(phosphonic) acid ester or esteramide radical,R.sub.4 and R.sub.5 each independently is hydrogen, alkyl with 1 to 3 carbon atoms or halogen, or R.sub.4 and R.sub.5 conjointly form a fused benzene ring, andX is oxygen or sulfur,Which possess insecticidal, acaricidal and nematocidal properties.

Abstract: O-Alkyl-S-?1,6-dihydro-6-thioxo-pyridazin-(1)-yl methyl!-(thiono)-(di)-thiol-phosphoric (phosphonic) acid esters and ester-amides of the formula ##STR1## in which R is alkyl with 1 to 6 carbon atoms,R.sup.1 is alkyl, alkoxy, alkylmercapto or alkylamino with a maximum of 6 carbon atoms per alkyl chain,R.sup.2 is halogen, alkoxy with 1 to 5 carbon atoms or alkyl with 1 to 5 carbon atoms,R.sup.3 and R.sup.4 each is hydrogen or conjointly form a fused benzene ring, andX is oxygen or sulfur atomWhich possess nematicidal and arthropodicidal, e.g. insecticidal and acaricidal properties.