The influence of fall and spring herbicide application on winter wheat

Non-Peer ReviewedThe use of 2,4-D for fall control of winter annuals weeds in winter wheat is recommended in the Canadian prairies but not in other winter wheat production areas. Field research was conducted for two years at several locations using 2,4-0, MCPA, dicamba, dicamba plus 2,4-D, bromoxynil, bromoxynil plus MCPA, chlorsulfuron and clopyralid applied fall and spring. Recommended and double recommended rates were tested to establish the existence of a safety margin. Norstar winter wheat was tolerant to fall applications of all herbicides when applied at recommended rates, however, grain yield was reduced at the double rate with 2,4-D, MCPA, bromoxynil, bromoxynil plus MCPA and clopyralid in some station years. Norstar was tolerant to spring applications of all herbicides except MCPA and clopyralid in several station years. Herbicides tested show promise for use in winter wheat production. Caution is warranted for spring application of MCPA and clopyralid