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New tool will help Ontario corn growers forecast DON risk

May 16, 2019  By Top Crop Manager

After an unprecedented year for mycotoxins in corn, the governments of Canada and Ontario are supporting the Grain Farmers of Ontario (GFO) to create a tool to forecast the risk of high concentrations of deoxynivalenol (DON) in corn crops.

The tool will help both conventional and organic corn farms to make early, informed decisions about their crops and the use of fungicide or other treatments that reduce the risk of DON. The tool will also help reduce DON-related challenges throughout the corn value-chain and is similar to a forecasting tool for wheat.

This adds to a series of actions taken by Canada and Ontario to support farmers and the sector in connection with weather-caused, high-DON levels experienced in portions of the 2018 Ontario corn crop. In 2018, wet conditions during the latter part of the growing season brought a lot of humidity to the corn canopy, which held moisture and was conducive to mould growth. Gibberella ear rot, the mould of main concern, produces the mycotoxin DON. The result was higher-than-normal DON levels, not seen since the last outbreak in 2006, being reported across Ontario, particularly in the west and southwest areas of the province. Some producers in the region reported DON levels of up to 30 parts per million, a far cry from the five parts per million that was considered high by buyers.


“We are pleased to have the support of the federal and provincial governments on this program. The repercussions of this year’s high-DON levels in corn are still being felt,” said Barry Senft, CEO of the Grain Farmers of Ontario. “Farmers would welcome a tool that allows us some forecasting in terms of DON levels and helps us to prepare for any issues and maintain our businesses and the province’s grain corn value chain.”

Government response

Previous government responses to DON-affected Ontario farmers, include:

  • Creating a tiered corn salvage benefit in support of requests from farmers who dealt with DON in their corn crop last year. The benefit will more accurately reflect the additional costs associated with harvesting and handling corn affected by DON and help farmers trying to find a market for it.
  • Establishing another partnership with the Grain Farmers of Ontario to develop best management practices for in-season mitigation of DON and for effectively managing the storage of high-DON corn.
  • The provincial government extending its Commodity Loan Guarantee Program loan repayment deadline, giving farmers affected by DON additional time to market their corn. The Ontario government also increased the maximum guaranteed loan limit, on a pilot basis, from $120 million to $200 million for the 2019 and 2020 program years.
  • Launching a cost-share program through the Partnership to provide special assistance to farmers experiencing revenue loss over testing for DON in corn.

In addition to the supports to help manage the impacts of DON, the Ontario government also hosted two roundtable sessions with industry representatives to work on connecting farmers with mental health supports and to provide solutions to help the sector find alternate markets for corn with high levels of DON.

Managing DON in corn

During Top Crop Manager‘s webinar, Corn Season in Review, corn specialists discussed the high-DON levels and existing management strategies to help reduce mycotoxin issues. Ben Rosser, corn specialist with the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA), said hybrid selection is one area growers have control over. While weather is the biggest factor when it comes to mycotoxin issues, there is a lot of variability in tolerance or susceptibility among corn hybrids. Rosser also suggested that growers should consider planting multiple hybrids to spread out the risk instead of planting one hybrid.

Rosser also explained that the silking stage is the optimal timing for spraying fungicides when trying to curb ear mould issues. Recent research out of the University of Guelph Ridgetown campus also confirmed this in a new study suggesting there may be little benefit to early-season fungicide/herbicide combinations for corn. The research supported Rosser’s suggestion and showed that the likelihood for economic returns increase when foliar fungicides are applied at silking.

The University of Guelph Ridgetown Campus also looked into a possible connection between western bean cutworm (WBC) damage and DON-levels after the 2018 growing season and found that WBC can exacerbate Fusarium infection and therefore, also exacerbate DON concentrations in corn. The study also posed some more recommendations for growers, such as recommending triazole fungicides instead of strobilurin fungicides for controlling DON.

The announcement of the GFO tool adds another resource for growers when it comes to the use of fungicide or other treatments that reduce the risk of DON.


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