Plant Growth Regulators can increase plant growth, minimize lodging risks and lead to better crop yields.
Manipulator, the brand name for chlormequat chloride, has been used by barley growers since 2020, and Moddus, the brand name for trinexapac-ethyl, has been used since 2021.
In an on-farm trial in 2022, PGRs were found to reduce lodging in wheat. In the following year, the Manitoba Crop Alliance conducted barley trials with Manipulator and found that treated strips had lower crop height and reduced lodging.
Anne Kirk, a cereals specialist with Manitoba Agriculture, warned in a recent Crop Talk webinar that malt barley growers should check with buyers before using PGRs on their crops, and should also check the Keep It Clean website.
Why it matters: Plant growth regulators can lead to better plant growth and reduced lodging, but producers should check with the Keep it Clean initiative and with buyers before using them.
Keep it Clean, an organization formed by the Canola Council of Canada, Cereals Canada, Pulse Canada and the Prairie Oat Growers Association (POGA), released a product advisory earlier this year about market risks for producers who use chlormequat. Some grain buyers, such as food processing companies, could restrict the use of certain regulators and pesticides on crops they purchase.
“There are some market access issues with using some specific PGRs in malting barley,” said Andrew Hector, an agronomy extension specialist with the Manitoba Crop Alliance. He advises producers to check the Keep it Clean website regularly.
“If you’re thinking of using a PGR on malting barley specifically, you should talk to your grain buyer and confirm your contract obligations and acceptance before using that product.”
There are no product advisories for oats, but current MRLs for groats, rolled oats and oat bran are 35 parts per million. Canadian oat growers have been blamed by the Environmental Working Group, an American activist organization, for causing agricultural chemical residue in Cheerios and Quaker Oats products.
In a study released by the EWG in February on oats and chlormequat and published in the Journal of Exposure Science and Environmental Epidemiology, 77 of 96 human urine samples tested from 2017-23 showed the presence of chlormequat in adults in Florida, South Carolina and Missouri.
The EWG said such results were not overly alarming, but because chlormequat is linked to reproductive and developmental problems in animals, there is concern it could cause the same issues in humans. Growers in the United States aren’t allowed to use Manipulator, the brand name of chlormequat, so the EWG concluded the chemical in oat foods originated on Canadian farms.
Shawna Mathieson, executive director of POGA, said the only time she’s heard of buyers taking issue with use of PGRs is in the specialty market.
“They’re very specialized, such as organic or gluten free [companies],” she said, “[and] some of those won’t accept any PGRs.”
However, most producers haven’t had issues with other buyers, she said. POGA research indicates less than 20 per cent of producers in the Prairies and Western Canada use PGRs.
“[PGRs] have been tested by multiple different organizations, including Health Canada, and have been approved, so there’s no issue on that.”
Mathieson is critical of the EWG study, stating the amount of residue found was 300 times lower than the maximum residue limits. The study also did not ask participants where they worked, or specifically if they worked in greenhouses, which use a lot of PGRs.
Mathieson encourages producers to read PGR labels and apply them at the right time.
“Our producers are very, very good about that. No one wants to overuse or use a product that isn’t necessary … and we would encourage our growers to make sure that before they apply PGR, they check with their buyers and make sure it’s allowed.”
Source: Manitoba Cooperator