Synergistic composition comprising a sulfonylurea and a thiadiazolo[3,4-a]p y

Abstract

The present invention relates to a synergistic composition comprising a herbicidally active gulfonylurea of formula I ##STR1## wherein Z is a substituted phenyl, thiophenyl, benzyl, pyridinyl, pyrazinyl, hetero-fused phenyl, or alkylsulfonylamino radical; M is hydrogen; or C.sub.1 -C.sub.4 alkyl; and Het is a substituted five- or six-membered heterocycle having 2 or 3 nitrogen atoms, and a synergistically effective amount of a 5,6,7,8-tetrahydro-1-H,3H-(1,3,4)-thiadiazolo[3,4-a]-pyridazine or 7,8-dihydro-1-H,3H-(1,3,4)-thiadiazolo[3,4-a]pyridazine of formula II ##STR2## wherein X is oxygen; or sulfur; A--B is --CH.sub.2 --CH.sub.2 --; or --CH.dbd.CH--; and Phe is a substituted phenyl radical. The composition according to the invention is suitable for selective weed control in crops of useful plants, especially in cereals, maize, rice or soybeans. The invention relates also to a method of controlling weeds in crops of useful plants, especially in cereals, maize, rice or soybeans, and to the use of the novel composition.

Dependencies are inferred from the claim text.