Abstract
The fumigants 1,3-dichloropropene (1,3-D) + chloropicrin (Pic) and metam-Na have provided erratic nutsedge (Cyperus spp.) control in the field. To determine if the activity of these fumigants against yellow nutsedge (Cyperus esculentus L.) varies with tuber growth stage, a greenhouse experiment was conducted using two fumigation treatments (1,3-D + 35% Pic at 327 L*ha[sup-] and metam-Na at 294 L·ha[sup-] ) and a nonfumigated control, two tuber sources (Gainesville and Quincy), three tuber growth stages (dry, water-imbibed, and sprouted at planting), and two metam-Na rates (147 or 589 L·ha[sup-]) applied to imbibed tubers. Pans containing the soil and tubers were covered with polyethylene film for 3 d after treatments (DAT). In spring 2000, both fumigants provided 100% nutsedge control. In winter 2001, metam-Na provided 100% nutsedge control while 1,3-D + Pic provided near total control with greater activity against imbibed than dry tubers. Nutsedge control of [greater than or equal to] 89% was obtained with both fumigants for 28 DAT. Results indicated that nutsedge activity of 1,3-D + Pic may be optimized by irrigation prior to treatment, and that of both fumigants enhanced by minimizing fumigant out-gassing.
