Growth Retardation of Bermudagrass with Metsulfuron Methyl and Sulfometuron Methyl¹

Abstract

Abstract Our primary objective was to determine optimum times and rates for applications of metsulfuron methyl (MSM) (methyl 2‐[(([(4‐methoxyd‐methyl‐l,3,5‐triazin‐2‐y1) amino] carbonyl) amino) sulfonyl] benzoate) and sulfometuron methyl (SMM) (methyl 2 [(([(4,6‐dimethyl‐2‐primidinyl) amino] carbonyl) amino) sulfonyl] benzoate) to reduce mowing requirement without adversely affecting the aesthetic value of the bermudagrass [ Cynodon dactylon (L.) Pers.] turfgrass. Field studies were conducted on mature bermudagrass lawn turf grown on a Captina silt loam soil (fine‐silty, mixed, mesic Typic Fragiudalt). Results of 1982 and 1983 experiments showed that MSM alone produced much less growth reduction than a combination of MSM and SMM. The combination at rates of 35 + 35 and 70 + 70 g ha −1 and higher produced good growth suppression for 6 to 8 weeks followed by a flush of growth, but excessive discoloration injury especially when repeated at 5‐week intervals. In 1984 the combination applied at 8.8 + 8.8 on 24 May, 17.5 + 17.5 on 28 June, and 35 + 35 on 2 August provided excellent growth retardation (70% mowing reduction) all season with only very slight injury. The influence of irrigation and N fertilization was minimal.