With reports of stripe rust in southeast Kansas, area wheat producers are concerned their yields may be affected by disease in their stands.
“I think stripe rust is our primary concern right now,” says Erick DeWolf, K-State extension plant pathologist. “Producers need to be scouting for the disease.”
He warns producers stripe rust can be very damaging, causing significant yield loss.
In a special edition of the K-State Agronomy eUpdate on April 23, DeWolf and Doug Shoup, K-State southeast area crops and soil specialist, reported industry sources found stripe rust in Labette County on Monday, April 20. The next day, a heavy infection of stripe rust was confirmed near Altamont. Stripe rust lesions take a couple weeks to become visible after the initial infection so lesions from stripe rust are most likely from wet periods of rain on April 2 or April 7, they explained.
“There were several ‘hot spots’ of stripe rust in the field,” they wrote, “and you could easily find stripe rust lesions on the flag leaves throughout the rest of the field.”
DeWolf says there is a lot of variability in fields.
“If producers are finding fields with good yield potential and are finding the disease on the flag leaves of 1 to 2 percent of the plants, it would warrant a fungicide application,” DeWolf says. “If no stripe rust is found or it is in the lower canopy, they may be able to delay a fungicide application until more information can be gathered. Many fields may not need a fungicide application if the disease remains at low levels."
He did offer hope, saying stripe rust is influenced by temperature and moisture so if the area returns to a dryer weather cycle, producers may experience only mild yield loss. Nighttime temperatures of 60 degrees or above would also help slow the progress of the disease.
Bob Hunger, Oklahoma State University extension wheat pathologist, says he has heard of some disease in east and central Oklahoma.
“I had a call the other day from a consultant from east-central Oklahoma concerned about fusarium head blight,” Hunger says. “They hadn’t seen that much but the conditions were right and were considering recommending spraying.”
He also states he has heard about a fairly good amount of stripe rust in eastern Oklahoma but not many cases of leaf rust.
“The weather is ideal for foliar diseases to get going,” he says.
He has seen several samples from western and central Oklahoma test positive for wheat streak mosaic and also mentions seeing a bit of powdery mildew in those areas.
Laura Sweets, University of Missouri plant pathologist, says she hasn’t received any calls about diseases in southwest Missouri wheat fields with the exception of one call about wheat soilborne mosaic.
“Overall, wheat looks pretty good,” says Pat Miller, MU agronomy specialist. “Some of the stands didn’t tiller a lot so they’re a bit thinner stands.
“Wheat should be heading out, if it’s not already,” Miller continues. “Once it starts heading, it’s past the time for spraying for foliar disease. The time for spraying head disease is when it is starting to bloom.”
She has not seen any wheat disease in southwest Missouri like the outbreak of stripe rust in southeast Kansas, she says. However, she does recommend producers be out looking for diseases.