Effect of adjuvants on control of nutsedge (Cyperus esculentus and C-rotundus) by imazapic and imazethapyr

Purple and yellow nutsedge control by imazapic and imazethapyr at 0.05 and 0.07 kg ai/ha applied alone or with crop oil concentrate (Agri-Dex(R)) at 1 .0% v/v, nonionic adjuvant (Chaser(R)) at 1.0% v/v, nonionic surfactant (Ki netic(R) Hv and Silken(R)) at 0.125% v/v, sticker-extender (Plex(R)) at 1.0 % v/v, methylated seed oil (Sun-It IF) at 1.0% v/v, or nonionic spreader an d activator (X-77(R)) at 0.25% v/v were evaluated in field studies from 199 3 to 1996. Control with imazapic was greater for both species regardless of rate or adjuvant for both yellow and purple nutsedge control. Crop oil con centrate, nonionic adjuvant, nonionic surfactant, or sticker-extender incre ased efficacy of imazethapyr over imazethapyr without an adjuvant. Yellow n utsedge control with imazapic was lower with the nonionic spreader and acti vator. No advantage in purple nutsedge control was observed when adjuvants were added to imazapic. The benefit of adjuvants appear greater for imazeth apyr than imazapic. (C) 2000 Elsevier Science Ltd. All rights reserved.