Wet season emphasizes chemical caution

Farmers will need to watch their pre-harvest intervals carefully or risk running into residue problems

Reading Time: 3 minutes

Published: July 17, 2024

Blackleg on a canola plant.

Late seeding this year will require producers to watch pre-harvest intervals for any pesticides they apply.

“That’s really critical, especially this year,” said Ian Epp, an agronomy specialist and market access and pesticides lead with the Canola Council of Canada.

“There are a lot of products that have one- or seven-day PHIs (pre-harvest intervals), but there are also 30- and 45-day PHIs, and for some of our earliest crops, we’re going to start getting into that window here really soon.”

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Cutting within the minimum number of days between spray and harvest risks market implications if that grain is found to have unacceptable chemical residue.

Why it matters: Soggy fields have hindered timely seeding and spraying in Manitoba, with most of the province reporting above-average rainfall through May and June.

Epp is part of Keep It Clean, a joint initiative between the Prairie Oat Growers Association, Cereals Canada, Canola Council of Canada and Pulse Canada to monitor and spread critical information on potential market risks from certain products. The organization also provides resources to ensure crops meet domestic and export standards.

“The worst-case scenario is that something goes into the stream, is shipped and rejected down the stream, and then they trace it back to the farm,” said Epp. “Then we have a problem.”

The group has a list of five tips for farmers to make sure they don’t run up against those standards.

Acceptable pesticides only

Pesticides must be registered for the crop planted and they shouldn’t conflict with Keep It Clean’s annual product advisories. It there’s any uncertainty, Epp said, the grower should talk to their grain buyer.

“Sometimes, maybe you have something that’s a little bit offside or you’re not quite sure about. Your grain buyer will know those things that will be able to walk you through it.

“And maybe, if there is something that’s a little bit trickier to deal with, they might have a spin. They might have a special market that’s safe to deal with.”

Label is king

Farmers should always read the label for application rate, timing and pre-harvest interval. It is illegal to disregard label instructions and it can cause big problems for industry.

“If we go off label, sometimes we might see residues that haven’t been anticipated, and suddenly we have market risk that can be traced back down to the farm,” Epp said.

Manage disease

Producers should keep on top of disease pressures. While it makes good agronomic sense to manage disease, Keep It Clean warns that it can also affect market access. Toxins like deoxynivalenol found in grain infected with fusarium blight can shut market doors.

Producers are familiar with most disease management steps, such as opting for disease-resistant genetics and spreading the crop rotation. Epp also stressed year-round scouting and disease identification.

This year’s conditions have many producers watching carefully. Cool, wet conditions followed by a forecasted hot summer translates to friendly conditions for many field pathogens.

Store it properly

Proper crop storage will help keep grain free of cross-contaminants and avoid pest control measures that could create market risk.

“This is a sneaky one,” said Epp. “A lot of growers don’t have problems with bugs in their bins every year. It might have been four or five years since you’ve had a problem.”

If there is a problem, he added, use the right product. Malathion, for example, should be avoided in canola.

“Keep your bins cool and dry and ventilate everything to reduce the risk of disease or pests in your bins,” Epp advised.

Deliver what you declare

This tip refers to the Declaration of Eligibility affidavit, a legally binding statement that confirms that a crop matches what’s on the form.

“We have to be up front with what we’re declaring,” said Epp.

Other good practices

Good records are important, as is reading and understanding the declaration, Epp said.

“If you do have something you’re not sure about, talk to your grain buyer and ask specific questions about what this means. Again, if there is something that’s maybe a grey area and you’re not quite sure, your grain buyer might have a second market.”

About the author

Don Norman

Don Norman

Associate Editor, Grainews

Don Norman is an agricultural journalist based in Winnipeg and associate editor with Grainews. He began writing for the Manitoba Co-operator as a freelancer in 2018 and joined the editorial staff in 2022. Don brings more than 25 years of journalism experience, including nearly two decades as the owner and publisher of community newspapers in rural Manitoba and as senior editor at the trade publishing company Naylor Publications. Don holds a bachelor’s degree in International Development from the University of Winnipeg. He specializes in translating complex agricultural science and policy into clear, accessible reporting for Canadian farmers. His work regularly appears in Glacier FarmMedia publications.

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