Collaborators: Calvin Yoder - Alberta Agriculture & Forestry, Akim Omokanye - Peace Country Beef & Forage Association, Kim Schoorlemmer - DuPont Pioneer
From: Peace Country Beef & Forage Association 2016 Annual Report
Corn acreage in the Peace River Region for livestock feed has steadily increased over the past number of years. Most of the corn seeded is Roundup Ready (RR) which provides a good system for controlling weeds. Volunteer RR canola is also a common weed on fields where corn is grown. Managing volunteer RR canola in RR corn requires a broadleaved herbicide that can be mixed with glyphosate and be safely applied prior to seeding corn or applied in-crop.
Selecting a corn herbicide should be based on weeds present, crop stage, crop tolerance and price. There are a number of broadleaved herbicides that can be tank mixed with glyphosate and used on corn as pre-seed or in-crop applications. Tank mixing a broadleaved herbicide with glyphosate will improve control of a number of weeds including volunteer RR canola. Herbicides that can be tank mixed with glyphosate and applied prior to seeding corn are Heat, Pardner, Conquor, MCPA and 2,4-D. Some herbicides that are registered for use on corn and can be tank mixed with glyphosate include Pardner, Buctril M, 2,4-D, MCPA, Banvel and a new herbicide Armezon. Although Banvel, 2,4-D and MCPA are registered for use on corn, agronomists prefer not to recommend them as they can cause stunted growth and poor brace root development resulting in lower yields. Bromoxynil, which is the main active ingredient of Pardner, tends to be safer although can cause some leaf burn.
Methods
Trials were conducted in 2015 and 2016 to evaluate several herbicide tank mixes with Roundup WeatherMax to control volunteer RR canola and other weeds in field corn. One trial in 2015 compared several treatments applied prior to seeding (Table 1) and the second trial conducted in 2015 and 2016 compared treatments applied in-crop (Table 2). All treatments included in the trials are registered for use on corn.
Experimental design for the Pre-Seed Herbicide trial was a randomized complete block design with three replications and plots were 2m x 7m in size. Experimental design for the 2015 In-Crop Herbicide trial was a randomized complete block design with 2 replicates. Experimental design for the 2016 In-Crop Herbicide trial was a randomized complete block design with 4 replicates.
Herbicides were applied with a hand held plot sprayer, calibrated to deliver 100 l/ha of water at 270 kPa.
Pre-seed Herbicide Applications