Turfgrass management method

A method for retarding growth and suppressing seed heading in turfgrasses, which comprises applying to the foliage or soil surrounding said turfgrasses a composition comprising a solid or liquid diluent and an imidazolinone compound, in an mount sufficient to retard growth and suppress seedheading in turfgrass, having the structure:

• ##STR7## wherein X is N or CR.sub.3 ;
• R is hydrogen;
• C.sub.1 -C.sub.12 alkyl optionally substituted with one of the following groups:
• C.sub.1 -C.sub.4 alkoxy, halogen, hydroxyl, C.sub.3 -C.sub.6 cycloalkyl, benzyloxy, furyl, phenyl, halophenyl, C.sub.1 -C.sub.4 alkylphenyl, C.sub.1 -C.sub.4 alkoxyphenyl, nitrophenyl, carboxyl, C.sub.1 -C.sub.3 alkoxycarbonyl, cyano or tri(C.sub.1 -C.sub.3) alkylammonium;
• C.sub.3 -C.sub.12 alkenyl optionally substituted with one of the following groups:
• C.sub.1 -C.sub.3 alkoxyl, phenyl, halogen or C.sub.1 -C.sub.3 alkoxycarbonyl, or with two C.sub.1 -C.sub.4 alkoxy groups or two halogen atoms;
• C.sub.3 -C.sub.6 cycloalkyl optionally substituted with one or two C.sub.1 -C.sub.3 alkyl groups;
• C.sub.3 -C.sub.10 alkynyl;
• or
• a cation;
• R.sub.1 and R.sub.2 are each hydrogen, halogen, C.sub.1 -C.sub.6 alkyl, C.sub.1 -C.sub.4 hydroxyalkyl, C.sub.1 -C.sub.6 alkoxy, C.sub.1 -C.sub.4 alkythio, phenoxy, C.sub.1 -C.sub.4 haloalkyl, OCF.sub.2 CHF.sub.2, OCF.sub.3, OCHF.sub.2, nitro, cyano, C.sub.1 -C.sub.4 alkylsulfonyl, NR.sub.4 R.sub.5, C.sub.3 -C.sub.8 straight or branched alkenyloxy optionally substituted with one to three halogens, C.sub.3 -C.sub.8 straight or branched alkynyloxy optionally substituted with one to three halogens, or phenyl optionally substituted with one C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkoxy or halogen;
• R.sub.3 is hydrogen, halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1 -C.sub.4 alkythio, C.sub.1 -C.sub.4 alkoxyl, CF.sub.3, NO.sub.2, OCF.sub.3, OCHF.sub.2 or OCF.sub.2 CHF.sub.2 ;
• R.sub.4 is hydrogen or C.sub.1 -C.sub.4 alkyl;
• R.sub.5 is C.sub.1 -C.sub.4 alkyl;
• and, when taken together, R.sub.1 and R.sub.2, in the case of X.dbd.CR.sub.3, may form a ring in which R.sub.1 R.sub.2 is represented by
• (1) the structure:
• --(CH.sub.2).sub.n --, where n is an integer of 2, 3 or 4;
• or
• (2) by the structure:
• ##STR8## where L, M, R.sub.6 and R.sub.7 each represent hydrogen;
• halogen, C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.3 alkoxy;
• and, in the case of X.dbd.N, R.sub.1 R.sub.2
• (1) may form a ting in which R.sub.1 R.sub.2 is represented by the structure --(CH.sub.2).sub.n --, where n is an integer of 3 or 4;
• or
• (2) when taken together with the carbons to which they are attached may form a 5-membered ring containing one O or S;
• or
• (3) may form a ring represented by the structure;
• ##STR9## where L, M, R.sub.6 and R.sub.7 each represent hydrogen, halogen, C.sub.1 -C.sub.4 alkyl, C.sub.1-C.sub.4 alkoxy, C.sub.1 -C.sub.4 alkylthio, C.sub.1 -C.sub.4 alkylsulfonyl, C.sub.1 -C.sub.4 haloalkyl, NO.sub.2, CN, phenyl, phenoxy, amino, C.sub.1 -C.sub.4 alkylamino, diloweralkylamino, chlorophenyl, methylphenyl, phenoxy substituted with one Cl, CF.sub.3, NO.sub.2 or CH.sub.3 group, OCF.sub.2 CHF.sub.2, OCF.sub.3, OCHF.sub.2, C.sub.3 -C.sub.8 straight or branched alkenyloxy optionally substituted with one to three halogens, or C.sub.3 -C.sub.8 straight or branched alkynyloxy optionally substituted with one to three halogens;
• or an N-oxide thereof when X.dbd.N provided that R cannot be alkenyl or alkynyl and R.sub.1 and R.sub.2
• cannot be NR.sub.4 R.sub.5 or alkylthio;
• an optical isomer thereof or a mixture of region isomers thereof, alone and in combination with N-›2,4-dimethyl-5››(trifluoromethyl) sulfonyl!amino!phenyl!-acetamide.