Postemergence Control of Large Crabgrass and Goosegrass in Turf

Abstract

Single and repeated applications of MSMA (monosodium methanearsonate) with and without 2,4-D [(2,4-dichlorophenoxy)acetic acid], metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazine-5(4H)one], and methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-di-one] were evaluated for control of large crabgrass (Digitaria sanguinalis L. Scop.) and goosegrass (Eleusine indica L. Gaertn.). Large crabgrass was controlled satisfactorily at Griffin in 1972 and 1973 with a single application of 1.7 kg/ha of MSMA, however, repeated applications were required for similar control at Griffin in 1974 and at Blairsville in 1973 and 1974. Repeated treatments at 0.6 kg/ha resulted in satisfactory large crabgrass control in only 2 of 3 years at Griffin and 1 of 3 experiments at Blairsville. The optimum time interval between the first and second MSMA treatments (average 1973 and 1974) was 12 days for the 1.1 kg/ha rate and anytime between 12 and 19 days for the 1.7 and 2.2 kg/ha rates. There was no advantage in large crabgrass control from treatments of methazole, metribuzin, or combinations of MSMA + 2,4-D when compared with MSMA. Single applications of 1.1 kg/ha of metribuzin or 2.2 kg/ha of methazole resulted in excellent goosegrass control without causing any permanent injury to common bermudagrass [Cynodon dactylon (L.) Pers.]. Repeated treatments of 3.3 kg/ha of MSMA were required to obtain satisfactory goosegrass control.