Bermudagrass [Cynodon spp. (L.) Rich.] is the most popular turfgrass planted in warm-humid regions (Beard, 1973). Improved seeded cultivars of common bermudagrass [Cynodon dactylon (L.) Pers.] have color, quality, and texture comparable to hybrid bermudagrass (Cynodon dactylon × C. transvaalensis Burtt-Davy) (NTEP, 2008). Potential-to-seed common bermudagrass provides turf managers with an establishment option that is unavailable for vegetatively propagated hybrid bermudagrass and may allow practitioners to replant areas following weed control with herbicides (Beard, 1973). Cool-season grasses and winter annuals are often problematic weeds in bermudagrass during spring and early summer. Actively growing weeds may out-compete bermudagrass for light, water, and nutrients during dormancy or early spring growth (McCarty et al., 2005). Controlling winter weeds with herbicides may reduce weed competition during spring greenup and allow turf managers to establish a uniform bermudagrass turf. Nonselective herbicides, such as glyphosate or glufosinate, may be used to control weeds on completely dormant bermudagrass, but applications during spring greenup may cause unacceptable injury and stand loss (Toler et al., 2007). Thus, selective postemergence herbicides are used for weed control in spring as bermudagrass emerges from winter dormancy. Rimsulfuron and sulfosulfuron are sulfonylurea herbicides used for weed control in bermudagrass (Chaleff and Mauvais, 1984; Dupont, 2004; Monsanto, 2008). These herbicides effectively control grassy weeds, such as tall fescue (Festuca arundinacea Schreb.), perennial ryegrass (Lolium perenne L.), and roughstalk bluegrass (Poa trivialis L.), and broadleaf weeds, including common chickweed (Stellaria media L.), henbit (Lamium amplexicaule L.), and field pansy (Viola rafinesquei Greene) (Dupont, 2004; McCullough and Hart, 2008; Monsanto, 2008; Morton et al., 2009). Simazine is a photosynthesis inhibitor used for controlling numerous grassy and broadleaf weeds and may be safely applied to established bermudagrass during spring greenup (Johnson, 1982; Tworkoski et al., 2000; Syngenta, 2008). Simazine is efficacious for postemergence weed control, but treatments may also have significant soil residual activity that may affect turfgrass seedling establishment (Tworkoski et al., 2000; Cummings et al., 2009; Hixson et al., 2009). Reseeding bermudagrass over areas once occupied by patches of weeds may be desirable following rimsulfuron, simazine, or sulfosulfuron treatments. Therefore, these herbicides may be used for renovating bermudagrass with other mixed species to reestablish bermudagrass turf (McCarty et al., 2005; McCullough and Hart, 2008). The objective of field experiments was to investigate bermudagrass reseeding intervals following rimsulfuron, simazine, and sulfosulfuron applications.
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