Quantifying the risks associated with late and sequential herbicide applications in herbicide-resistant canola

The Challenge

Although late applications of glyphosate have been shown to have detrimental effects on cotton, soybean, and corn, little is known about late glyphosate application effects on canola reproduction, seed set, yield, and quality.

The Project

Analyze the reproductive ecology, seed set, yield, and quality of canola exposed to late herbicide applications for all three herbicide resistant canola systems (glyphosate, glufosinate, and imidazolinone), and exploring the anatomical, morphological, and molecular causes of tolerance issues.

The Results

Imidazolinone resistant system showed no significant effects on any variable measured when imidazolinone was applied late and sequential. When glufosinate and glyphosate were applied late and sequential to their respective system, the risk of yield and economic loss was severe.

Grower Benefits

More research needs to be done on thresholds, but when spraying off-label, producers must contemplate their loss due to emergent weeds against significant yield loss due to late herbicide applications on their canola system. When applying off-label, growers assume all risk.