Simazine Formulation Treatments on Control of Winter Weeds in Bermudagrass Turf1

Abstract

AbstractExpanding choices of herbicides for consistent control of winter annual weeds are needed in turfgrass throughout the Southeast. Therefore, an experiment was conducted on Cecil sandy loam (Typic Hapludult) to determine effects of formulations, rates, and dates of simazine [2‐chloro‐4, 6‐bis(ethylamino)‐s‐triazine] treatments for the control of winter annual weeds in bermudagrass [Cynodon dactylon (L.) Pers.] turf.The most consistent control of winter weeds from preemergence treatments applied in September occurred from the 1.8 and 2.2 kg/ha granule rates and 2.2 kg/ha wettable powder treatment. Slurry treatments applied in September did not effectively control parsleypiert (Alchemilla microcarpa Boissier Reuter) or corn speedwell (Veronica arvensis L.). Postemergence February treatments generally controlled parsley‐piert, corn speedwell, hopclover (Trifolium agrarium L.), and annual bluegrass (Poa annua L.) effectively (80% or higher) regardless of rates and formulations. An exception occurred with granular formulation for hop clover as the control from the 0.9 kg/ha rate was not as good as when treated with other formulations at the same rate. February granular treatments did not satisfactorily control spur weed (Soliva spp), whereas, at least 70% of weeds were controlled with 1.8 kg/ha or higher rates of wettable powder and slurry treatments. However, spur weed control was improved significantly from repeated September and February treatments when compared with single treatments at selected rates. None of the simazine treatments delayed early growth of bermudagrass in the spring regardless of formulation, rates, or dates of treatment.