Resistance Management School: Getting a handle on fungicide resistance


As growers actively manage herbicide-resistant weeds on their farms, many are also looking at how to secure future effectiveness of other crop protection tools, including fungicides and insecticides.

In this first episode of a new season of RealAgriculture’s Resistance Management School, we take a look at the current state of fungicide resistance in field crops in eastern Canada with Albert Tenuta, plant pathologist with the Ontario ministry of agriculture. He believes industry efforts to increase awareness of herbicide resistance have also put fungicide and insect resistance on growers’ radar screens.

Fortunately, Tenuta reports, no cases of fungicide resistance have been documented in Ontario field crops, but there have been incidents of resistance recorded in the U.S. with frog-eye leaf spot and other corn pathogens. “It’s certainly a new area of concern. The good news is we are not there yet… but it’s something growers need to be aware of — the potential for fungicide resistance.”

When it comes to recognizing whether their fields are at risk, Tenuta says the first thing growers need to look for is declining fungicide efficacy. If growers are applying a foliar fungicide or a seed treatment and not getting the same level of control they have seen in the past, they could have a problem developing. If additional fungicide applications are required, that’s a big red flag, he says. (Story continues after the video.)

Tenuta believes the best way to manage fungicide resistance is to prevent it from gaining a foothold in the field. To achieve that, best management practices to promote healthy plants are critical. “We need to put the plant in position to defend itself against multiple pathogens and diseases.”

For corn, that starts with selecting the right germplasm. For example, if a field has a history of northern corn leaf blight (NCLB), growers need to select a hybrid that is tolerant or resistant to the disease, notes Tenuta. Cultural practices that promote early plant establishment and planting into fit conditions, whenever possible, are also key best management practices.

It’s also important to evaluate disease control. Get out and scout, says Tenuta. Growers need to identify what diseases are occurring in their fields so they can choose the right product and achieve a high level of efficacy. Is the crop suffering from a bacterial disease or a fungal pathogen like NCLB, asks Tenuta? “If you are targeting a bacterial disease with a fungicide it is not going to work because they are meant to manage fungal pathogens.”

In the video, Tenuta also discusses the need to select fungicides strategically and effectively manage them to maximize efficiency.

Click here for more Resistance Management School episodes.

Wake up with RealAgriculture

Subscribe to our daily newsletters to keep you up-to-date with our latest coverage every morning.

Wake up with RealAgriculture

Please register to read and comment.


Register for a RealAgriculture account to manage your Shortcut menu instead of the default.