Purple Nutsedge Control by Halosulfuron or Imazaquin/MSMA in Turfgrass in the Tropics

Abstract

ABSTRACT Field and greenhouse experiments were conducted to determine the extent of purple nutsedge (Cyperus rotundus L.) control in bermudagrass (Cynodon spp.) turf by halosulfuron (methyl 5- [[(4, 6-dimethoxy-2-pyriiTUdinyl)-amino]carbonylaminosulfonyl]-3-chloro-l-H-pyrazole-4-carboxylate) or imazaquin (2-[4,5-dihydro-4-methyl-4-(l-methyIethyl)-5-oxo-lH-imidazol-2-yl]-3-quinolinecarboxylic acid)/MSMA (monosodium methanearsonate), and to determine the extent of purple nutsedge regrowth from basal bulbs after foliar treatment with these herbicides. Excellent initial control (> 80%) of emerged shoots of purple nutsedge occurred with halosulfuron or imazaquin + MSMA. However, purple nutsedge shoots emerged within 3 or 4 weeks after all treatments, and nutsedge shoot density increased with time. With a rapid increase in purple nutsedge shoot density, the extent of control deteriorated rapidly, even after two applications of halosulfuron. Both halosulfuron at 70 g ha−1 and imazaquin at 0.42 kg ha−1 + MSMA at ...