Target spot can make Delta soybeans go south in a hurry
Sponsored by: BASF
Worst-case scenario: severe defoliation
Best-case scenario: Proactive protection for full-yield potential
The thing about target spot fungus in your soybeans or cotton is that it used to be “hit or miss,” but now it’s just “hit.”
2016: hit harder.
What is sure is that during the 2016 cropping season, target spot was one of the most widespread and severe foliar diseases of soybeans in the Delta and mid-South states. Several reports by consultants revealed significant defoliation in the range of 50-80%, and that contributed to at least a 15-20 bu/A loss.
Cotton growers know this all too well, too, since this is the same fungus that affected the 2016 cotton crop, some of it devastating. So the emotions for growers are raw, and right on the surface — just like target spot itself on the leaves.
Symptom development begins in the lower canopy with circular lesions, usually about 1/4” to 1/2” in diameter, with concentric rings (the “target”).
To the casual observer, a field may appear normal from a distance. But it can be a costly mistake not to inspect your plants up close by getting out in the field, examining the lower canopy, even down to the petioles, pods and stems that can also be infected by target spot.
Some of the key environmental factors that favor disease progression include prolonged conditions (typically 5-7 days) of high relative humidity, or free moisture provided by rain or heavy dew plus warm temperatures. Several days of consecutive rainfall or irrigation will also increase the severity of disease development.
Arkansas soybean grower and crop consultant Jason McGee has an interesting perspective: He believes that some of the newest practices that are generally good for high yields may be creating some of the conditions for target spot. “We control the irrigation so much better than we used to, pushing yields by pushing water down the rows more frequently,” McGee says. “But that intensity of field management that drives yields also creates a high humidity environment, which we know target spot likes.”
So what does he use, and when does he use it? “We’ve tried a lot of fungicide programs, and nothing is as effective as Priaxor® fungicide,” McGee says. “Spray it early or you’ll be chasing your tail.” He recommends growers look really hard at R2 for ideal timing. “My experience is that you have to get on it pretty quick,” he says, “and Priaxor fungicide at R2 is my go-to for target spot.”
What if you miss an application window? McGee has seen devastating results: “I’m aware of normally 65-bushel acres cut into the teens…13, 15 bushels. Those were extreme cases, but they were real. Big losses,” McGee adds. In other cases, he has seen fairly widespread fields with 20 bu/A losses.
“It got people’s attention,” McGee says. “I promise you they won’t be ignoring it if the conditions are there again this time.”
From ag universities to crop consultancies, and farmers with boots on the ground, the experts agree: Target spot is not to be taken lightly. And before the going gets tough, go with the best: Priaxor Xemium® Brand fungicide.
Always read and follow label directions.
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