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Spring cereals
Pre-Seed Herbicides

Let's talk problem weeds: Wild oats



Wild oats are an annual grassy weed many associate with the Prairies. Group 1 resistant populations have been found in Ontario, eliminating the primary control option for wild oats in spring cereals.

Wild oats


Reduced tillage can help keep seeds dormant in the seed bed. Apply Focus® Herbicide pre-plant or pre-emerge to reduce wild oats and broadleaf weeds in spring and winter wheat crops.


What the Research Says


Wild oats are a grassy annual weed many associate with the Prairies. However, herbicide resistant populations of wild oats have been reported in Ontario, greatly effecting spring cereal production. These populations are resistant to Group 1 herbicides, the primary control option for wild oats in spring cereals. Fall or spring applications of nitrogen fertilizer can stimulate germination of this problem weed. Wild oats can be distinguished from cultivated oats when they’re mature due to their long and bent or twisted awn. When placed in water this awn causes the wild oat spikelet to twist, digging the seed deeper into the seed bed.

Yield loss depends on the size of the weed relative to the stage of the crop. Yield loss is minimized the more advanced the crop is when the wild oats emerge in the spring. If the wild oats are a leaf stage ahead of a wheat crop, yield can be reduced by 15%. If the wild oats are a leaf stage behind the crop, yield can be reduced by 5%.

Some cultural management strategies include reduced tillage, to keep dormant seeds deep in the seed bed, and crop rotation.

Research is currently being conducted at the University of Guelph to see if wild oat populations in Ontario are resistant to all Group 1 herbicides or only certain Group 1 chemical families. There are three chemical families within Group 1, the Fops (ex. Fenoxaprop), the Dims (ex. Sethoxidim), and the Dens (ex. Pinoxaden). Each family targets the same target site in the plant but has a different chemical structure. Preliminary research has shown that certain wild oat populations in Ontario are resistant to some families and susceptible to others.


Article authored by:

Emily Duenk

Emily Duenk

Research Technician Intern

2020 – B.Sc. in Agriculture – University of Guelph

Emily is a recent graduate of the University of Guelph where she received her Bachelor of Science in Agriculture, majoring in Crop Science. She grew up outside of Ilderton, Ontario on her family’s farm where they cash crop and raise beef cattle. Emily enjoys showing beef cattle and has her own small herd of cows. During her undergrad, Emily became interested in weed science, competing on the university Weeds Team, and plans to complete her master’s degree at the U of G Ridgetown campus, studying herbicide resistant weeds.




Cowbrough, M. (2020, March 30). Pest Patrol: Herbicide-resistant wild oats in spring cereals. Country Guide

Hall, M. (2004). Integrated Weed Management Principles: Reducing the Risk of Crop Failure. 

OMAFRA. (2020, January 24). Ontario Weeds: Wild Oats. Retrieved from 

Raine, M. (2017, May 7). Weed of the week: wild oats. The Western Producer