As temperatures rise and winter wheat begins to break dormancy, a university specialist and Syngenta recommend growers keep a close eye on their crops to identify early signs of disease that may reduce grain quality and yield potential.
Due to the unusually long winter and late-arriving spring, wheat will likely move more quickly through growth stages as it reacts to more consistent temperature warm-ups, according to Brian Norton, Syngenta agronomic service representative in Kansas. Now that there will be fewer cold snaps that cause setbacks, it is important to scout fields early and often for potential pest outbreaks. Wheat plants determine maximum yield potential early in the developmental process, so it is especially important to eliminate potential disease threats and ensure a healthy start.
“Wheat plants determine the maximum number of potential spikelets per head at Feekes Growth Stages (FGS) 4 and 5, which is a key component for determining maximum yield potential,” Norton said. “It is important at this stage to make sure wheat is not being stressed by diseases and is utilizing water and nutrients as efficiently as possible.”
Some early-season diseases to watch for this spring include powdery mildew and tan spot in the northern states; leaf rust in the Pacific Northwest; and stripe rust in the South. These diseases can devastate wheat fields and may reduce yields.
Syngenta urges growers to proactively manage these diseases. An application of the right fungicide helps safeguard wheat against the yield-robbing diseases mentioned and Septoria. Wheat plants can maintain green leaves longer, improving plant quality and maximizing yield at harvest. Killing disease spores and providing residual protection has to be the goal.
Syngenta promotes the use of its Quilt Xcel, which has two modes of action for both preventive and curative disease control, to help manage wheat diseases throughout the season.
According to Gene Milus, plant pathologist at the University of Arkansas, an early-season fungicide application can be a cost effective way to manage stripe rust pathogens that overwinter in wheat. Controlling stripe rust early reduces the spread of infection to other plants and fields, keeps the pathogen population size low and allows time for resistance to be expressed in adult plants.
In addition to applying a preventive fungicide industry experts offer the following recommendations to help minimize potential threats from early-season diseases.
A good indicator that wheat may need extra protection is the level of disease presence in states located to the south. Many diseases can spread through windblown spores, so being aware of conditions further south can inform growers if and when to take preventive action.
“Now is the time that we begin paying attention to what is happening in states to the south,” said Erick De Wolf, wheat extension pathologist at Kansas State University. “For us, the first indication that we may experience stripe rust or leaf rust pressure is if we hear reports from Texas or Oklahoma. When they start having problems, we take that as a warning.”
Scout early and often
Scouting fields early allows growers the chance to take action at the first sign of disease. “I recommend growers start scouting their fields early and continue throughout the entire season,” said Jill Herold, Syngenta agronomic service representative in Montana. “It is much easier to prevent diseases than try to control them once they are already present in the field.”
When scouting for disease, pay close attention to the top and bottom of the leaves of the wheat plant. Powdery mildew infections will look like small, irregular or circular gray-white spots on leaves at flowering. Signs of stripe rust include small, yellow or orange blister-like lesions, also known as pustules. Leaf rust infections will take the shape of small, round or oval raised orange-red pustules on leaf surfaces. To view images of these diseases, visit Tools to Grow More Wheat an agronomic resource page. Areas that are experiencing a cool, wet spring are especially at risk for disease infection. As always in working with growers, agronomists and consultants should be suspicious of an infection and send a tissue sample to a plant disease diagnostic clinic.
Following a colder than normal winter, it is important to keep wheat healthy as it will likely experience a reduced developmental period. Being proactive and keeping a close eye on wheat helps avoid playing catch-up later.