• Lentils
• Seeding
• Soil Health
• University of Saskatchewan

Objective

To determine the efficacy of pre-harvest herbicides in reducing weed seed production in kochia and wild mustard.

Outcome

In Experiment 1, applying dicamba, 2,4-D amine, and glyphosate to wild mustard reduced seed production by 51, 54, and 72%, respectively. Glyphosate also reduced mustard seedling emergence by 52% in the following spring, and resulted in similar or better lentil yield than no weed wiping. In contrast, dicamba caused >50% yield loss, and therefore is not recommended for weed wiping in lentil. The optimal timing of weed wiping varied from year to year. In general weed wiping was most effective if it was conducted in the first or second week of wild mustard bolting. Weed wiping twice, in the first and third week of mustard flowering, was at least equally effective to wiping once at the optimal timing. In Experiment 2, different herbicides and concentrations reduced weed seed production inconsistently, and to a lesser degree, than in Experiment 1. Increasing the concentration lowered weed seed production for all herbicides on tame mustard, and five of seven herbicides on volunteer canola. Glyphosate, mecoprop, 2,4-D amine, 2,4-D amine + glyphosate, and mecoprop + glyphosate reduced mustard seed production by an average of 35%. Strong winds (approx. 50 km/hr) on the date of herbicide application may have played a role in the lower efficacy of weed wiping in Experiment 2 than Experiment 1.

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