Posted April 24, 2015
MANHATTAN, Kan. - As the 2015 Kansas wheat crop continues to develop, wheat producers need to be cautious about a growing threat of stripe rust moving across the state. This disease has the potential to cause losses of 40% or more to a wheat crop when it occurs prior to heading on susceptible varieties.
According to K-State Research and Extension (KSRE), industry sources in southeast Kansas reported a heavy infection of stripe rust near Altamont, and several more moderate cases around Labette County. KSRE also reports stripe and leaf rust may be active in Barber, Ottawa, Allen, Bourbon and Anderson counties. Farmers statewide should begin scouting their fields in search of stripe rust and other diseases.
"Stripe rust is an important disease of wheat in Kansas," said Erick DeWolf, professor of plant pathology at Kansas State University. " We have experienced several severe outbreaks of stripe rust in the last decade. Many of the most common varieties in the state are vulnerable to the disease including Everest, Armour and TAM 111."
Stripe rust thrives in cool, humid climates, which most of the state is experiencing. The disease grows rapidly between 50-60 degrees Fahrenheit, but is inhibited when night-time temperatures reach 68 degrees Fahrenheit or after several days of temperatures in the mid 80s.
While many producers with sparse infections may choose to "wait and see" while monitoring the disease closely, others with more intense infections may choose to apply fungicides. If farmers choose to spray, special care should be taken to adhere to label instructions.
"Fungicides may be warranted if the disease is found on the upper leaves prior to heading," DeWolf said. "Fields with a good yield potential should be the top priority. If the disease is still restricted to the lower leaves, fungicides may not be needed; however, it is important to keep checking because stripe rust can increase rapidly."
Evaluating the affect of current crop economics is also important. KSRE estimates that it could take at least a 5-bushel yield response to a fungicide application to break even, but notes that stripe rust is a disease that can be damaging and is not one to take lightly.