Whether cereal growers plan to treat for leaf disease or fusarium head blight, fungicide timing is essential — but this spring, in which many acres were seeded in a very short stretch, complicates matters.
Kristina Polziehn, technical specialist with BASF, says farmers in such a situation with a lot of acres to cover may need to start spraying at the start of a stage.
“Flag leaf, we’ve got a little bit of extra time in there, so it’s not a two-day window. But for fusarium head blight, it definitely is much more of a narrow window and important for them to get it on,” she says.
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Once the head is emerging from the boot, farmers only have a day or two to spray for fusarium, depending on the variety and weather conditions, she says.
“So we know the ideal timing is really that early flower, but if guys have a lot of acres, they’re not going to have a 24-hour window to do that.”
“I know that it is a short (application) window, but that’s the best agronomic advice that we can give to growers,” says Piero Castro, BASF brand manager for cereal fungicides.
Treating cereals at the flag leaf stage protects the crop from leaf diseases, while a second application at flowering protects against fusarium. Castro says BASF, for example, offers a two-pass system.
Polziehn says fusarium is moving across the Prairies — and there’s been chatter in the industry about doing a second application.
“So in areas where you might have more disease pressure, or maybe we’ve pushed our rotations, there is that value to come in and do a second application,” she says.
Higher prices are also making wheat more attractive to farmers, leading to more investments in inputs and interest in protecting yields, she says.
“For them, a fungicide is part of protecting the yield. If you’re putting the nitrogen (down) early in the season, you’ve invested all this money into herbicides and seed treatments, you want to protect that investment later on.”
Managing resistance
To reduce the risk of chemical resistance, Polziehn says, BASF puts out products that are “truly multi-mode.”
Thus, “if one active ingredient has resistance built to it — an example would be stromboli resistance — (there’s enough of) the other active ingredient to provide full disease control.”
For example, she says, Twinline has both a Group 3 and Group 11 active ingredient, each of which on its own would provide disease control. “But together there’s a bit of a synergy to give you really good disease control.”
Saskatchewan Agriculture has several suggestions for preventing fungicide resistance. They include rotating fungicide groups, mixing fungicides that are at risk of losing effectiveness with fungicides from a different group, watching disease in crops for signs of resistance, having an integrated pest management program, and not exceeding the maximum number of applications on the label.
— Lisa Guenther is a field editor for Grainews at Livelong, Sask. Follow her @LtoG on Twitter.
