Extension notes is written by K-State Extension of Harvey County extension agents Scott Eckert, Susan Jackson and Ryan Flaming. They focus on horticulture and agriculture.
The forecasts of snow are now hopefully behind us and wheat greening up in Kansas; it may surprise some wheat growers to know March was an important month for wheat disease development.
@Body type RR:“It turns out that February and March are important because we often receive our first reports of disease activity from states to our south,” said Erick De Wolf, plant pathologist with K-State Research and Extension. “This is particularly relevant for the rust diseases, which often survive the winter in these southern climates.”
Wheat leaf rust is fungal disease that affects wheat, barley and rye stems, leaves and grains. Infections can lead up to a 20 percent yield loss. Wheat leaf rust is spreads via airborne spores.
Small brown pustules develop on the leaf blades in a random scatter distribution. They may group into patches in serious cases. Infectious spores are transmitted via the soil. Onset of the disease is slow but accelerated in temperatures above 60 degrees, making it a disease of the mature cereal plant in summer, usually too late to cause significant damage in temperate areas.
So far this year there are several reports of rust developing in Texas, Arkansas, Louisiana and Mississippi, De Wolf said. Stripe rust has been observed in all four states and appears to be spreading beyond the initial foci of infection. Leaf rust has been reported in Texas, but not the other states.
The reports of stripe rust and leaf rust from Texas are the most important for Kansas, because weather systems often transport the rust spores from Texas into Oklahoma and Kansas. Varieties such as Everest, Armour, and TAM 111 are being affected in Texas this year. This is similar to what was observed in 2012 and there are no reports of new races of stripe rust to date.
De Wolf said that Bob Hunger, a wheat disease specialist with Oklahoma State University, reported no finds of rust in Oklahoma as of March 21.
“Growers in Kansas should be monitoring the situation in Texas and Oklahoma. If the disease continues to develop in Texas or is reported in Oklahoma, we will need to evaluate the need for fungicides to suppress rust development in fields planted to susceptible varieties,” he said.
— Ryan Flaming is a Kansas State Research and Extension Agent for Harvey County. Agriculture is his specialty.