Canadian cereal growers can protect their investment and help to maintain market access for everyone by carefully planning and managing pre-harvest glyphosate applications.

The following special considerations should be taken when applying glyphosate pre-harvest:

  • Wheat: only use pre-harvest if greenest part of the crop is <30% moisture.
  • Oats: only use pre-harvest if greenest part of the crop is <30% moisture and talk to your buyer, oats may not be accepted by grain buyers if treated pre-harvest.
  • Malt Barley: will not be accepted by grain buyers if treated pre-harvest.


Press a thumbnail into the kernel with moderate pressure. If the indent bounces back, the crop is not dry enough to receive glyphosate application. | photo: Charlee McLaughlin

Fall application of glyphosate is of special interest to our customers for two key reasons:

  1. Glyphosate has come under increased scrutiny, when compared to other pesticides, due to recent media attention generated by those who do not support the use of pesticides for any reason;
  2. Unlike many products applied in fall, applying glyphosate when kernels are too green (30% moisture or above) can result in residues that are greater than the maximum allowable limit.

If growers spray pre-harvest glyphosate when seed moisture content is above 30 per cent, traces of the product can be absorbed by the plant as it dries, leaving unacceptable residues behind. Because glyphosate will accumulate in the seed itself, longer storage time after the crop has been cut does not reduce residue levels. 

What Can Farmers Do?

  • Do not apply glyphosate to cereals when kernels are 30% moisture or greater in the least mature areas of the field.
  • Some customers have contract limitations on fall application of glyphosate. Talk to your grain buyers to ensure they know what crop protection products you intend to use, and to confirm that none of these products will cause concern for export or domestic customers.

Farmers’ rigorous adherence to these guidelines, including the science-based label, will keep this important product in our toolbox for years to come.

Click here to learn more about special considerations for managing your pre-harvest glyphosate applications.