a blanket of foam averaging 3 inches thick the foam blanket slowly broke down depositing the active ingredients on the blades of grass no discoloration was observed on the kentucky bluegrass treated with these agents applied as a foam this dosage was equivalent to four pounds of active ingredients a i acre of ethrel plus 2 pounds a i acre of sustar the reduced rate of growth was evident after one week and continued for approximately six weeks the rate of growth was about half that observed in the untreated control plots the following representative data are presented to demonstrate the effectiveness of the inventive combinations to regulate the growth of turf grasses the data also illustrates the significant benefits obtained by the inventive combination as contrasted to untreated turf and to the use of either agent of the combination singly the ratio of weights in agents employed and of dosages applied to the grass are indicative of the best modes of practicing this invention an aqueous solution of 1 part by weight of sustar and from one to two parts by weight of ethrel was prepared the effects of the specific combinations of ethrel and sustar were evaluated on flats of kentucky bluegrass variety fylking after three weeks under greenhouse conditions table i______________________________________inhibition of growth of fylking kentuckybluegrass at 3 weeks after foliarapplication in greenhouse agent dosage lbs acre growth inhibition______________________________________ watercontrol 5 0ethrel 3 21sustar 2 8ethrel 2 11ethrel amp 3 46sustar 2ethrel amp 2 38sustar 2______________________________________ note that in the application of 3 ethrel 2 sustar one would expect a cumulative growth inhibition of about 29 21 8 however a synergestic 46 growth inhibition was obtained similarly in the case of 2 ethrel 2.