Herbicides for Seasonal Weed Control in Turfgrasses1

Abstract

AbstractCommercially available preemergence herbicides do not consistently control weeds in turfgrasses satisfactorily in the Southeast. New herbicide tests to determine if weed control could be improved were conducted on several soil types over a 3‐year period. Several herbicides were applied in early spring and evaluated for the control of large crabgrass (Digitaria sanguinalis L. Scop) in bermudagrasses [Cynodon dactylon (L.) Pers.] and Kentucky bluegrass (Poa pratensis L.) turf or they were applied in early fall and evaluated for the control of annual bluegrass (Poa annua L.) and other winter annuals in a bermudagrass turf. Soil types were Cecil sl and Cecil scl (Typic Hapludult), Appling loamy sand and Appling scl (Typic Hapludult), Madison scl (Typic Hapludult), Hatboro 1 (Typic Fluvaquents), and Davidson scl (Rhodic Paleudult). Oxadiazon [2‐tert‐butyl‐4‐(2,4‐dichloro‐5‐isopropoxyphenyl)‐ Δ2‐1,3,4‐oxadiazolin‐5‐one] applied in early spring at 4.5 kg/ha was better than with other herbicides tested for large crabgrass control. Oxadiazon was the only herbicide that consistently controlled large crabgrass at all locations. Parsley‐piert (Alchemilla microcorpa Boissier Reuter), a broadleaf winter annual not previously reported, was controlled satisfactorily when oxadiazon was applied preemergence in the fall. No other herbicide controlled parsley‐piert as well as oxadiazon.