Abstract: The invention provides the acaricidal thiadiazoles of the formula: ##STR1## (where: R.sup.1 and R.sup.2, which may be the same or different, are each hydrogen, optionally-substituted alkyl of 1 to 10 carbon atoms, or optionally-substituted phenyl, of R.sup.1 is alkylthio of 1 to 6 carbon atoms; R is an ester-forming group; Y is oxygen or sulphur; and the carbamate grouping is in the 3- or 4-position on the phenyl ring), processes for their preparation and compositions containing them.

Abstract: Herbicidally-active compounds of the formula: ##STR1## where: Y represents halo or trifluoromethyl;Z represents hydrogen, halo, trifluoromethyl or nitro;A represents --N.dbd. or ##STR2## where X is as defined above for Z; and R represents --N.sup.- Q.sup.+ or --NH--Q.sup.+ An.sup.- where Q.sup.+ is a quaternized heterocyclic group bonded through a nitrogen atom thereof, and An.sup.- is a suitable anion,methods for their preparation and compositions containing them.

Abstract: The compounds of the formula: ##STR1## wherein R.sup.1 represents phenyl substituted in at least the 2-position by fluorine, chlorine, bromine or iodine, R.sup.2 represents a group R.sup.3, --OR.sup.3, --SR.sup.3 or --NR.sup.3 R.sup.4 where R.sup.3 represents hydrogen, alkyl of 1 to 6 carbon atoms, cycloalkyl of 3 to 7 carbon atoms, alkenyl of 2 to 6 carbon atoms, cycloalkenyl of 3 to 7 carbon atoms, alkynyl of 2 to 6 carbon atoms, phenyl, phenylalkyl of 7 to 10 carbon atoms or naphthyl, each of which may be unsubstituted or substituted by one or more halogen atoms, alkyl or alkoxy or alkylthio groups of 1 to 6 carbon atoms, nitro groups, cyano groups or mercapto groups, R.sup.4 represents a group as defined for R.sup.

Abstract: There are provided the compounds of the formula: ##STR1## (wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4, which may be the same or different, each represent hydrogen, a substituted or unsubstituted alkyl, aryl or aralkyl group, a nitro group, a cyano group or a halogen atom, R.sup.5 represents a quaternized nitrogen-containing heterocyclyl radical linked via a ring carbon atom, X represents one equivalent of an anion, R.sup.7 represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted, saturated or unsaturated heterocyclyl group which, if nitrogen-containing, is quaternized, linked via a ring carbon atom, and R.sup.6 either represents an alkyl group or, when R.sup.7 represents a quaternized nitrogen-containing heterocyclyl group, and the quaternized nitrogen atom is ortho to the linked ring carbon atom, may represent a methylene, dimethylene, trimethylene or alkyl-substituted ethenylene chain to that nitrogen atom.The compounds are selective herbicides.