If you have a good-looking cereal crop, fungicides generally pay for themselves — even when disease pressure is low
It’s impossible to predict how much moisture different regions of the Prairies will receive during the critical period for disease development, but it’s fair to say that, overall, conditions have generally trended dry over the last several seasons. And since moisture is one of the key factors for disease development, some are asking if it still makes sense to spray, given these prolonged dry conditions. The data says yes.
“Even in very dry areas we saw a nice yield response in the treated versus the untreated check in the majority of our trials,” says Kate Hadley, a market development agronomist with Bayer in Saskatchewan. “The yield bump in wheat, averaged almost five bushels per acre in our 2023 trials, which is significant in a really dry year and makes a compelling argument when it comes to your return on investment.”
Real-world trials
Bayer’s market development group has conducted field-scale trials using growers’ own equipment and field practices. The group has been running these trials since 2008. Last year, 21 wheat trials were conducted under a range of growing conditions.
In very dry areas, no significant differences were seen in grain quality because of low disease presence, says Hadley. But the yield bump from applying fungicide, covered the cost of that application while providing insurance against potential weather events.
Fungicides can help plants use water more efficiently, allowing them to stay green longer. And a plant that stays green longer late into the season can reach full maturity and yield potential. Research shows a fungicide application could increase photosynthetic activity and provide better plant stress tolerance. Some research has shown that fungicides also slow plant respiration, releasing less moisture, making them more drought tolerant at the end of the season, again, allowing them to fully mature and produce higher yields.
“At the end of the day, growers want higher yields,” says Hadley. “It’s harder to sell the idea of a fungicide when it’s dry and disease presence is low. But when you know you will get a yield advantage and you take that risk of disease development off the table, that is a long-term approach to disease management.”
Tackling key cereal diseases
Troy Basaraba is a market development representative with Bayer in Manitoba. He works closely with the breeding and research and development group and conducts fungicide trials using Bayer’s equipment to test specific issues with grower co-operators. In 2023 he and his team conducted eight field-scale trials, plus a second set of trials on market development farms to test some agronomic issues.
Cereal crops are more predictable when it comes to disease, says Basaraba. The more common diseases include tan and spot rots, Septoria complex, and fusarium head blight (FHB) and growers typically look at rotations and the disease package in their seed as part of a whole disease management plan.
“A fungicide application protects your (seed) investment,” says Basaraba. “It starts at the planning stage and then you tweak accordingly. If you have had anything from fusarium to leaf disease to sclerotinia in the past — which most growers have — you know you have inoculum. That third piece of the disease triangle, the weather, is always changing and something as minor as dew can set things into action. Risk assessment maps can show you your level of risk, but you need to be prepared to act when your crop is ready.”
Timing it right
As agronomists, Hadley and her colleagues are getting an increasing number of questions from cereal growers about applying fungicide at T2 versus head timing, the idea being that bringing the sprayer out only once is a more efficient use of resources. But she says she doesn’t usually recommend T2 fungicide applications, especially if the field has a history of fusarium infection.
“You can’t predict the weather and you only have one shot to get it right,” she says. “We know the inoculum for fusarium is present across the Prairies and all it takes is for the weather to change at the right time for FHB to take hold, so we still recommend application at the head timing and following the label guidelines.”
Predicting disease on the Prairies is never an easy task. It depends on the weather not only here, but in the U.S. where many leaf diseases blow in from. It also depends on what inoculum was able to overwinter.
In Alberta, a few relatively dry years have likely lowered inoculum levels in soil and stubble, but disease is still present across the province. Saskatchewan has had both dry and wet conditions recently, so disease levels are regionally dependent. Manitoba saw a return to more normal moisture conditions in 2023, and its usual humid climate means fungicide applications tend to be standard there.
“This season I would plan to apply at T3 in all wheat and barley crops in case it shapes up to be a good growing season,” says Hadley. “If everything is looking strong, apply at T3 to protect your yield and you will have a plan in place against disease, regardless of the environment.”
Be prepared
Basaraba is located in western Manitoba, and says that last year, it was an interesting season to watch develop. “We had unbelievable yields in 2023,” he says. “And you could see that from early in the season. It was a bit drier in many areas, but we still had the potential to pull off the biggest yield in years. We have had some big disease years so growers here plan for a fungicide application because they know they need to protect their investment.”
If a crop is underperforming due to drought, planning for a fungicide application and pulling the plug is always an option, he adds. “If you plan for a fungicide with a good-looking crop, at least you have it ready to go. You can watch as rust blows in. You can watch the situation in the States and see what leaf diseases are moving up. You can watch the risk maps. If your crop looks good, you are ready to apply without delay when the time is optimal.”
Fungicide is a protectant with no real downside from an agronomic sense, says Basaraba. “Why do we keep doing trials after 16 years? Because there are always more questions to answer,” he explains. “Yes, products continue to evolve, but we are always checking how we use them — is our timing still right, are our water volumes still ideal? The questions just keep on coming and, to be on the forefront of agronomic knowledge, we need to keep testing the latest technology.”
In terms of return on investment, both Hadley and Basaraba use a simple ROI math equation as a starting point for a conversation on the value of a fungicide. But Basaraba says that everyone’s grain marketing strategy is different, so the value proposition is different for every farmer.
“Everyone is very cognizant of farm margins, but how ROI is measured varies by grower experience,” he says. “Fungicides have proven themselves over the long term and we have proven in virtually every type of growing condition that they are a valuable investment. Even if you have a drier bias — if you have a good-looking crop coming — why wouldn’t you try and maximize it?”
If you are curious about the disease issues in your growing region this coming season, contact your local agronomist, stay on top of provincial disease risk maps and watch the weather. To view Bayer’s fungicide demonstration trial results by crop and year, visit the online Fungicide DST map.