Preemergence Winter Weed Control in Dormant Bermudagrass Turf 1

Spur weed ( Soliva sessilis P. & K.) is becoming a severe winter weed problem in the Southeast and information is needed on herbicides that will give satisfactory control of winter weed mixtures which includes spur weed. Field experiments were conducted for 2 years on Cecil loam (Typic Hapludult) and Cecil sandy loam at Griffin, Davidson sandy clay loam (Rhodic Paleudult) at Lawrenceville and 1 year on Cecil loam at Macon, Ga., to determine the effects of preemergence herbicide treatments on control of spur weed and other winter annuals in bermudagrass [ Cynodon dactylon (L.) Pers. ‘Common’] turf. Herbicides as preemergence treatments were made in the fall and weed control and turfgrass tolerance ratings were made the following spring. Napropamide [2‐( α ‐naphthoxy)‐ N , N ‐diethylpropionamide] was the only herbicide that controlled spur weed almost completely. The control was acceptable with terbutol (2,6‐di‐ tert ‐butyl‐ p ‐tolyl methylcarbamate) at 11.2 kg/ha and profluralin [ N ‐(cyclopropylmethyl)‐α,α,α‐trifluoro‐2,6‐dinitro‐ N ‐propyl‐ p ‐toluidine] at 6.7 kg/ha. Combination treatments of bensulide [0,0‐diisopropyl phosphorodithioate S‐ester with N‐(2‐mercaptoethyl) benzene sulfonamide] with either benefin ( N ‐butyl‐ N ‐ethyl‐α,α,α‐trifluoro‐2,6‐dinitro‐ p ‐toluidine), terbutol, or pronamide [3,5‐dichloro‐( N, ,1,1‐dimethyl‐2‐propynyl)benzamide) controlled more different weed species than when each was applied alone. All herbicides except oxadiazon [2‐ tert ‐butyl‐4‐(2,4‐dichloro‐5‐isoproxyphenyl)‐Δ 2 ‐l,3,4‐oxadiazolin‐5‐one], butralin [4‐(l,l‐dimethylethyl)‐ N ‐(l‐methylpropyl)‐2,6‐ditrobenzenamine], and selected bensulide plus benefin combinations affected the green‐up of bermudagrass at one location in March and April. However, turf greenup was as good or better in all treated plots when final ratings were made in May.