Published on Fri, 07/13/2018 by BASF Canada

Crop staging is critical for pre-harvest weed control in cereals

There is a renewed focus on cereal crops in Canada this year. The annual seeded acres for all cereal crops – including durum, barley and spring wheat – have increased more than 10 percent from 2017 to reach 24.7 million acres, according to Statistics Canada.

As harvest approaches, managing weed pressure will soon be top-of-mind: a clean field makes for a quicker harvest, and it is easier to store grain when green matter is kept to a minimum. Growers are reminded to carefully follow label recommendations for pre-harvest aids, as improper use and application timing can impact marketability.

The Keep it Clean! campaign from Cereals Canada is focusing heavily on this message for 2018 as Canadian cereal exports are under increased scrutiny for quality control and testing. The premise behind the campaign is to educate growers on the steps to maximize export marketability. Brenna Mahoney, director of communications at Cereals Canada noted, “Growers need the right information at the right time in order to make the most informed decisions for their farm.  This is the main goal of the Keep it Clean program.”  Mahoney continued with, “As market access issues can change rapidly, we need to be able to get information our quickly to farmers.  This helps protect their business as well as the entire value chain.” 

Keep it Clean! - cereals also outlines special considerations related to glyphosate and crop staging. While glyphosate is approved for pre-harvest use in wheat, spraying it after a crop has reached maturity can leave residues on the crop and jeopardize marketability within major grain export markets.

“Many growers know the benefits of pre-harvest herbicides for late-season weed control, but timing is critical to manage residue limits,” said Melissa Parkinson, Crop Manager for Cereals at BASF. Last summer, CODEX Alimentarius Commission (CAC) established Maximum Residue Limits (MRLs) for Heat LQ as a harvest aid in cereals. This allowed BASF to establish MRLs in all major export markets to support the use of Heat LQ as a pre-harvest herbicide in wheat and barley with glyphosate.

“This is the first opportunity many growers will have to use Heat LQ on their cereal crops as a pre-harvest herbicide,” said Parkinson. “This will provide growers a tool to help dry down and manage tough broadleaf weeds like volunteer Roundup Ready canola. Controlling those weeds will lead to a cleaner sample, and also puts less stress on your combine.” Heat LQ is recommended to be tank-mixed with glyphosate for added activity on tough broadleaf weeds including Canada thistle, volunteer canola, and wild buckwheat.

Bruce MacKinnon has seen the impact of volunteer canola on cereals in Alberta. As a Certified Crop Advisor and BASF technical specialist in Lethbridge, MacKinnon has worked with growers looking for a solution to the rising problem of volunteers. “It’s a weed that can be quite difficult to manage if you don’t include a tank-mix partner for multiple modes of action. If you’ve used a Roundup Ready canola system in the past, glyphosate alone just won’t work – regardless of when you apply it,” he said.

Timing is one of the most important steps with any pre-harvest herbicide application and in determining what benefit you are hoping to achieve. “Pre-harvest herbicides work differently depending on which crop you are applying it to. For cereals, your pre-harvest goal is to control weeds – not to dry down your crop,” said MacKinnon. He recommends growers apply a pre-harvest aid when the crop has a moisture content of 30 percent or less, but before full maturity, and to use increased water volume of at least 10 gallons per acre to get full coverage.

BASF has established accepted MRLs for Heat LQ on wheat, feed barley and triticale. If you are planning to use Heat LQ on oats or malt barley, be sure to discuss with your grain buyer to adhere to their pre-harvest herbicide requirements.

For more advice on crop staging for pre-harvest herbicides in cereals, visit the Cereals Canada website www.KeepingItClean.ca/cereals.

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