Reduced-risk herbicide screening for pulse and oilseed crops
Project code: MU03-WEED3
Eric Johnson - Agriculture and Agri-Food Canada
To screen new, reduced-risk or low rate herbicides as potential weed control solutions in chickpea, dry bean, canola-quality mustard, sunflower and linola
Summary of Results
Pulse and oilseed crops provide a significant contribution to the Canadian economy, and for producers represent a high value addition to crop rotations. However the adoption of some alternative crops such as chickpea, dry bean, canola-quality mustard and linola is limited by the lack of sufficient weed control options. Growers of both pulses and alternative oilseed crops need access to efficacious and environmentally safe, low rate herbicides to improved opportunities for diversification.
Sixty-five screening and re-cropping studies were conducted over a 2-year period at three locations (Scott, SK., Indian Head, SK and Lethbridge, AB). Herbicides were screened in the following crops: chickpea, lentil, field pea, sunflower, yellow mustard, oriental mustard, flax, niger, prairie carnation, and foxtail millet. Carfentrazone-ethyl, was evaluated as a pre-plant or pre-emergence burndown treatment prior to the seeding of lentil.
Chickpea exhibited good to excellent tolerance to sulfentrazone and isoxaflutole. Both herbicides have residual properties and may cause injury to sensitive re-crops. Proposed rates of sulfentrazone for registration in chickpea (280 g ai /ha) may be higher than is required for effective weed control based on efficacy and re-cropping studies. Reduced rates of combinations of sulfentrazone and isoxaflutole showed potential to provide broad-spectrum weed control in chickpea, and this may reduce the potential for re-cropping injury.
Sunflower, flax, and peas exhibited fair to good tolerance to sulfentrazone at rates tested. Lentil and dry bean were more sensitive and weed control and tolerance should be evaluated at lower rates in these crops.
Yellow mustard may also tolerate lower rates of sulfentrazone. These screening studies provide the basis for further, targeted studies in these crops. Pre-plant burndown prior to the seeding of broadleaf crops can be problematic if volunteer glyphosate-tolerant canola is present. There are a number of tank-mix partners for glyphosate but many of them are short-term residual and can injure most broadleaf crops such as chickpea and lentil. Carfentrazone-ethyl is a reduced-risk contact non-residual PPO inhibitor that effectively controlled volunteer glyphosate-tolerant canola in field studies. High rates of carfentrazone applied pre-emergence to lentil did not result in significant damage or yield loss in lentil.
Data generated throughout the course of this project will be used to support registration submissions for new herbicide uses.
For more information, please contact: Eric Johnson at 1-306-247-2011
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