Small grains disease update: No drama in NY
The 2022 season for soybean and small grain growers was “not a dramatic season,” said Gary Bergstrom, plant pathologist with Cornell University, at the 2023 Soybean & Small Grains Congress. The Congress included presentations on yield promotion and disease and pest control.
New York experienced very warm weather last May with mostly low precipitation, followed by normal and variable weather and precipitation in June and warm weather in July with moderate to high precipitation. Closer to harvest, some farms experienced drought.
Bergstrom noted that soybean diseases of 2022 included only isolated reports of sclerotinia stem rot (white mold) and relatively low severities of most foliar fungal diseases, along with increased prevalence of Cercospora leaf blight, correlating with purple seed stain.
Soybean vein necrosis virus was more prevalent than in the past decade, but “it showed no signs of damaging yield,” Bergstrom said.
Some farms reported late-season diseases including pod and stem blight and some poor quality grain with downy mildew, Phomopsis/Diaporthe root and stem rot, seed rot, stem canker, brown stem rot and sudden death syndrome.
He advised farmers to select more resistant varieties to combat these fungal issues rather than spraying their soybeans.
Soybean cyst nematode pressure increased to 37 counties – all the soybean and dry bean production areas of the state. “A few years ago, we had just a few places in Cayuga County,” Bergstrom said.
So far, these areas have exhibited low egg counts in the soil, but he added, “It’s a good time to put into practice resistance strategies.”
He cautioned that nematodes are “becoming resistant to the resistance” because across the region, varieties with PI 88788 resistance are not hitting the mark of allowing less than 10% reproduction. On some farms, even half the nematodes reproduce.
“The recommendation is to choose a high-yielding, soybean cyst nematode-resistant variety and maintain rotation with nonhost crops,” Bergstrom said of low infestation areas. For moderate to high infestation, he said to perform frequent soil testing as well.
The Soybean Cyst Nematode Coalition (theSCNcoalition.com) offers “incredible information,” Bergstrom said as he encouraged producers to peruse its resources.
He also said that research on cover crops may help lower soybean cyst nematode numbers.
Research illustrates that higher levels of nematodes, including soybean cyst nematode and root knot nematode, contribute to the highest levels of yield loss.
As for other diseases and pathogens, frog eye leaf spot already has a high degree of fungicide resistance. New fungicides MiravisNeo and Regev may help.
Applying fungicide at three intervals with the third application at the 10.51 growth stage is important to its success. Rainfall doesn’t seem to affect fungicide’s efficacy, but a surfactant helps some. Operators have “better control with double applications, but it doesn’t always pay off,” Bergstrom said. “With a moderately resistant variety, you can get it down to almost nothing.”
For organic operators, he cautioned that “you really have to invest in moderately resistant varieties.”
Notable small grain diseases of 2022 included some powdery mildew in susceptible varieties of winter wheat, but few mycotoxin issues. Growers of malted barley experienced excellent quality. Those growing winter barley experienced little Fusarium head blight or mycotoxins, and some leaf rust and scald.
“Winter wheat had small yields, but good quality,” Bergstrom said. “Diseases were down from previous years.”
Low, pocketed areas showed greater prevalence of oat crown rust; however, resistant varieties have shown to be helpful.
“It comes in on the wind, plus buckthorn hedges in the woods,” Bergstrom said. “We think isolated incidences are because of buckthorn.”
Additionally, crown rust was spotted on cereal grasses, and on some on oats, fescue and lawn grasses.
by Deborah Jeanne Sergeant
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