Can you afford not to do a pre-seed herbicide application?

There’s still a need for pre-seed weed control in a rushed spring

*With files from Michelle Thompson, Brett Teetaert and Simon North

We’ve got another compressed spring ahead of us, and that makes everyone – us included – anxious to get a crop in the ground. But if you think this is a sign you can get away with skipping a pre-seed herbicide application, think again. We’ve seen some great moisture conditions across the Prairies, and we’re anticipating worse than normal weed pressure.

Control weeds early to give your crop a strong start

We recommend a pre-seed herbicide application using a mix of products with multiple modes of action. This timing is key to controlling weeds when they’re small, preventing them from robbing your crop of precious moisture and nutrients and ultimately preventing yield loss.  

The bonus is that you reduce the chance that weeds will outgrow staging restrictions for in-crop herbicides and you’ll increase the efficacy of your in-crop applications.

Give yourself in-crop spray timing flexibility

Doing a pre-seed burn also reduces your reliance on cooperative weather for in-crop spraying, when weather delays can allow weeds to get really competitive. Many products also have strict application windows and are not effective on large weeds.

Use multiple modes of action for better weed control

In recent provincial weed management surveys, approximately 50% of cleavers and 30% of narrow-leaved hawk’s beard1 were found to be resistant to Group 2 chemistry. We’re also seeing increasing resistance to glyphosate in kochia. Because there are limited options in-crop and so much Group 1, Group 2 and glyphosate being used in-crop, a pre-burn provides the ideal opportunity to use many different herbicide groups and can be a cost effective tool against resistance. Ultimately, you’ll get better control of big overwintered weeds by hitting them with multiple modes of action before they’re far more difficult or very expensive to control in-crop.

For example, you could target wild buckwheat in Roundup Ready® canola by using a pre-seed  burn that contains bromoxynil because in-crop glyphosate is not as effective on that weed. This will also help control canola volunteers, which are becoming more troublesome as canola rotations tighten. Canola volunteers not only compete with the seeded crop, but they also host pests. The seed from volunteers may also contaminate specialty canola crops.

Get the benefits of residual activity

Many pre-seed products shine based on their residual activity. Even if there are very few or no weeds present at the time of application, many have weeks of activity on emerging weeds, controlling or suppressing weeds during crop emergence and during the critical weed-free period where competition can be a big yield robber.

The active ingredient can be applied safely to the soil early on and heat up, making in-crop control so much easier. For example, Chickweed is often best controlled through residual products.

As a bonus, residual products can also give timing flexibility. Some pre-seed products, like Command® 360 ME, Focus®, Fierce® and Valtera™ can be applied early when soil is still too cold for seeding activities. This will help you get a jump on weed germination/emergence. 

Apply products like Korrex™ II, Express® Pro, Inferno® Trio and Intruvix™ when gaps in seeding arise, even when conditions are not conducive to heavy weed pressure.

Of all the operations you do on your farm this season, a pre-seed burn incorporating multiple modes of action is one of the best investments you can make. Even if you’re pressed for time this spring, achieving superior, cost-effective weed control more than outweighs the sacrifice of delaying seeding by a couple of days.

Always read and follow label directions.

Command, Express, Focus and Intruvix are trademarks of FMC Corporation or Affiliate.
Fierce® is a registered trademark  and Valtera™ is a trademark of Valent U.S.A. LLC.
INFERNO is a registered trademark of an Arysta LifeScience Group Company
Korrex is a trademark of Production Agriscience Canada Company, Corteva, Dow AgroSciences and Pioneer and affiliated companies or their respective owners.
Roundup Ready® is a trademark of Bayer Group, Monsanto Canada ULC licensee.


1 Source:  Agriculture and Agri-Food Canada and the University of Alberta

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