Abstract: A method of combatting plant nematodes which comprises applying to the soil or the plant, an effective amount of a compound of general formula I ##STR1## wherein Ar, X, R.sub.1, R.sub.2, R.sub.4 and R.sub.5 have the meanings given in the description, is described. Some of the compounds also form part of the invention.

Abstract: There are described new 2-imino-1,3-dithietanes of general formula I ##STR1## in which R is the group ##STR2## in which A is CFHal, C(CH.sub.3)C.sub.1-4 -alkyl, C(CH.sub.3)CHal.sub.3, C(CH.sub.3)CF.sub.2 Cl, C(CH.sub.3)CFCl.sub.2, C.sub.2 H.sub.4, C.sub.2 H.sub.3 Hal, C.sub.2 H.sub.2 Hal.sub.2, C.sub.2 HHal.sub.3, C.sub.2 F.sub.2 Cl.sub.2, C.sub.2 F.sub.4 or C.sub.2 F.sub.3 Cl, in which Hal is F or Cl,Y is nitrogen or CH,R.sup.1 is fluoro-C.sub.1-12 -alkyl, fluoro-C.sub.2-12 -alkenyl, fluoro-C.sub.2-12 -alkynyl, fluorocyclopropyl or fluorocyclopropylmethyl;X is oxygen or sulphur,2 is defined in the specification andn is 0, 1 or 2,as well as their acid addition salts, a process for their preparation and their use as pesticides. The new compounds are especially useful as nematicides.

Abstract: A pesticide which contains at least one compound of the formula ##STR1## in which Hal is halogen. The compositions have both a fungicidal and nematicidal action and have a high compatibility with agriculturally and horticulturally useful plants.

Abstract: Salts of carbamic and thiocarbamic esters are used having fungicidal and fungistatic action, said salts having the general formula ##STR1## wherein R is an aliphatic hydrocarbon radical with preferably 2 to 4 carbon atoms, X is oxygen or sulfur, and n is an integer from 2 to 4, with an inorganic or organic acid.

Abstract: New 1,3,4-thiadiazoles substituted in the 2 and 5 positions for use as soil and seed fungicides, nematocides and the processes therefor.

Abstract: The specification discloses the preparation and use, as fungicides and nematocides, of 2,5-substituted-1,3,4-thiadiazoles having the structure: ##STR1## wherein R.sub.1 is a lower haloalkyl and R.sub.2 is an aliphatic hydrocarbon.The instant invention is directed to methods for the control of fungi and nematodes in soil and seeds and to compounds useful in such methods. In another aspect, the invention is concerned with the preparation of 2,5-substituted-1,3,4-thiadiazoles and formulation for agricultural use in which such compounds are the principal biocidal ingredient.