Early Postemergence Herbicide Weed Control in Onions

Abstract

Oxyfluorfen (Goal®) herbicide at 0.25 lb. ai./A and bromoxynil (Buctril®) at 0.38 lb.a.i. /A applied early postemergence (POST) to onions at the 1- to 2-leaf stage of growth gave near complete control ( >98 %) of lambsquarters, knotweed, cheeseweed, London rocket, and good control ( -90 %) of shepherd's purse. Buctril® did not control annual bluegrass and Goal® only slightly reduced some of the heavy population. Both herbicides caused marginally unacceptable onion injury at 17-20 %. Buctril® plus pendimethalin (Prowl®) tank-mix combination applied POST also gave very good broadleaaved weed control but annual bluegrass was reduced only 50 %. Similar onion injury was observed for the combination treatment as Buctril® alone. Buctril® caused onion injury when it was applied during cloudy weather. Buctril® and Goal® were effective for broadspectrum broadleaved weed control but onions were sensitive when treated before reaching the full 2-leaf stage of growth. Cloudy weather during applications also intensified the onion injury by Buctril® treatments.