DCPA (dimethyl tetrachloroterephthalate), bensulide [O,O-diisopropyl phosphorodithioate S-ester with N-(2-mercaptoethyl)benzenesulfonamide], and oxadiazon [2-tert-butyl-4(2,4-dichloro-5-isopropoxyphenyl)-Δ2-1,3,4-oxadiazolin-5-one] were applied to bermudagrass [Cynodon dactylon (L.) Pers. ‘Common′] as consecutive repeated annual treatments or in all possible sequence combinations for 3 yr to determine the effects on species composition of winter and summer annual weeds. Regardless of the rotation of treatments on winter weeds, oxadiazon increased the cover of common chickweed [Stellaria media (L.) Cyrillo], spur weed (Soliva spp.), and thymeleaf sandwort (Arenaria serpyllifolia L.); bensulide increased the cover of corn speedwell (Veronica arvensis L.); and DCPA in most instances increased the cover of hop clover (Trifolium agrarium L.) and spur weed. When a herbicide controlled large crabgrass [Digitaria sanguinalis (L.) Scop.] or goosegrass (Eleusine indica L. Gaertn.), the cover of weeds not controlled increased rapidly, with the exception of oxadiazon applied for 3 consecutive yr.
