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Mild winters in the South allow for the fungal disease to survive, and windy weather could spread it north.

Mindy Ward, Editor, Missouri Ruralist

March 13, 2024

2 Min Read
A close up of yellow stripes on wheata wheat plant leaf
YELLOW STITCHES: Stripe rust on wheat may resemble a little of your grandma’s sewing. The fungus is already in the South, and if the weather and wind prevail, it could move into Missouri. Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org

Farmers should scout wheat fields for stripe rust this spring and have a fungicide application at the ready.

Stripe rust of wheat was confirmed early this year in Louisiana, says Mandy Bish, University of Missouri plant pathologist. It’s too close for comfort as the spores of the pathogen (Puccinica striiformis f. sp. tritici) can be dispersed by the wind over long distances, ultimately infecting Missouri wheat fields.

If the disease takes hold, especially in a susceptible variety, the impact can devastate a wheat crop. In severe cases, yield loss can reach upward of 70%, according to the Crop Protection Network, a partnership with university Extension specialists from across the country.

To mitigate risk, Bish says farmers should consider a fungicide application for susceptible wheat varieties, especially if forecasted conditions are favorable for the disease.

Fungus likes colder environment

Unlike leaf rust or stem rust that like warm temperatures, stripe rust is what plant pathologists consider a cool-season disease.

Early infection before or at the flag leaf stage tends to happen when overnight temperatures are between 50 and 60 degrees F, and when heavy dew or irrigation are present, Bish explains. Infection slows as minimum air temperatures rise above 73 degrees.

Farmers can identify stripe rust as a pattern of yellow to orange pustules that develop parallel to leaf veins after tillering and result in the characteristic stripes, Bish says. It often looks like stitches made from a sewing machine. Prior to tillering, pustules develop in a random pattern on leaf surfaces.

Fungicides that work on stripe rust

Many fungicides can be used to control stripe rust, but timing is important.

Applications at flag leaf emergence help reduce yield losses, Bish notes. “This is earlier than optimal applications for wheat scab but may be necessary,” she adds. “In some instances, a second application for stripe rust may be warranted.”

The fungicide will protect the plant for up to 28 days. New growth will not be protected. If weather conditions are favorable for stripe rust and the crop is still susceptible to yield loss, consider a second fungicide application. Wheat fungicide efficacy charts are available on the Crop Protection Network website.

For sample confirmation, consider submitting symptomatic plants to the MU Plant Diagnostic Clinic.

Read more about:

Stripe Rust

About the Author(s)

Mindy Ward

Editor, Missouri Ruralist

Mindy resides on a small farm just outside of Holstein, Mo, about 80 miles southwest of St. Louis.

After graduating from the University of Missouri-Columbia with a bachelor’s degree in agricultural journalism, she worked briefly at a public relations firm in Kansas City. Her husband’s career led the couple north to Minnesota.

There, she reported on large-scale production of corn, soybeans, sugar beets, and dairy, as well as, biofuels for The Land. After 10 years, the couple returned to Missouri and she began covering agriculture in the Show-Me State.

“In all my 15 years of writing about agriculture, I have found some of the most progressive thinkers are farmers,” she says. “They are constantly searching for ways to do more with less, improve their land and leave their legacy to the next generation.”

Mindy and her husband, Stacy, together with their daughters, Elisa and Cassidy, operate Showtime Farms in southern Warren County. The family spends a great deal of time caring for and showing Dorset, Oxford and crossbred sheep.

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