Broadleaf Weed Control in Dormant Bermudagrass Turf

Broadleaf weeds continue to be a major problem in turfgrass during mild winters throughout the Southeast. Therefore, experiments were conducted with herbicides applied postemergence to determine the maximum weed control with the least amount of chemical treatment. Two new herbicides alone with presently available chemicals were applied to dormant bermudagrass [Cynodon dactylon L. Pers.] in singly and repeatedly at 1 and 2✕ rates at three locations. Soil types were Cecil sl (Typic Hapludult), Durham scl (Typic Haludult), Gwinnett scl (Typic Rhodudult), and Pacolet-Wickham sl (Typic Hapludult). Parsley-piert (Alchemilla microcorpa Boissier Reuter) was completely controlled with single treatments of methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] and cisanilide (cis-2,5-dimethyl-N-phenyl-1-pyrrolidinecarboxamide) while two applications were required to obtain satisfactory control with silvex [2-(2,4,5-trichlorophenoxy)propionic acid], paraquat (1,1'-dimethyl-4,4'-bipyridinium ion), dicamba (3,6-dichloro-o-anisic acid), and combination treatments of 2,4-D [(2,4-dichlorophenoxy)acetic acid] with either dicamba, silvex + dicamba, or mecoprop {2[(4-chloro-otolyl)oxy]propionic acid} + dicamba. Paraquat resulted in excellent corn speedwell (Veronica arvensis L.) control with a single treatment, but two applications were required for similar control with cisanilde or methazole. Two applications were generally required of 2,4-D, silvex, dicamba and the two and three combination treatments for satisfactory corn speedwell control, especially in plots treated with 1✕ rates. All the herbicides gave good to excellent henbit (Lamium amplexicaule L.) and common chickweed [Stellaria media (L.) Cyrillo] control except for 2,4-D when applied to henbit at the 1✕ rate.