Published online by Cambridge University Press: 20 January 2017
Herbicides were evaluated for weed control and crop response in conventional and no-tillage dry pea production. Preplant or preemergence (PRE) applications of imazethapyr, sulfentrazone, flumetsulam, cloransulam, and BAY FOE 5043 + metribuzin did not show crop injury within the locations, years, and tillage systems where applied. Postemergence applications of cloransulam had crop injury in excess of 60% where applied, and injury with flumiclorac and fomesafen ranged from 0 to greater than 40% with differences in crop injury as a result of dry pea growth stage at the time of application and surfactant use. Imazamox injury was as great as 24% when applied at a more advanced dry pea growth stage and was not different from 0% when applied at an earlier growth stage. Dry pea injury with bentazon was not significant, with an exception at one of the six locations where injury was 14%. Common lambsquarters was best controlled (80 to 90%) with sulfentrazone and imazamox. Preplant and PRE applications of sulfentrazone consistently provided the greatest mayweed chamomile control across tillage systems (control ranged from 59 to 93%), whereas bentazon provided the greatest postemergence (POST) control of mayweed chamomile (control ranged from 46 to 84%). Prickly lettuce control with preplant or PRE treatments was greatest with sulfentrazone (74 to 85%), whereas the greatest POST control was with imazamox in combination with urea-ammonium nitrate solution and surfactant or bentazon and crop oil concentrate (71 to 92%). Dry pea yields with herbicide treatments were not always greater than the nontreated and were often affected by crop injury.