Some parts of Virginia have entered a moderate risk of scab, and a few localized areas have a severe risk (check your area using the Scab Risk Assessment Tool at www.wheatscab.psu.edu). This is the result of increased humidity, and the forecasted rain may increase infections of flowering heads by the scab fungus. The following recommendations were made on the Head Scab Prediction Center Website (www.wheatscab.psu.edu) by Nathan Kleczewski from the University of Deleware:

“Fields entering flowering are at the highest risk for scab. The best fungicides for scab are Prosaro, Caramba, and Proline. Do not apply products containing a strobilurin (e.g. Aproach Prima, Quilt, Stratego, Headline, Quadris, etc) as strobilurins have been associated with elevated DON levels when applied to the head and scab occurs. There is a 5-6 day window after the majority of a field is flowering and conducive weather occurs to make a fungicide application and maximize efficacy. Ground rigs should have nozzles angled at least 15 degrees in the forward direction and apply at least 10 gallons per acre, with 15-20 being optimal. Aerial applicators should apply at 5 gallons per acre. Shoot for 300 to 350 micron droplet size. Prosaro, Caramba, and Proline will control foliar diseases.””

These same recommendations apply to Virginia.

Foliar diseases of wheat also have the potential to increase at this time. Several fungicides have good to excellent efficacy in control of multiple diseases. Remember to avoid strobilurin containing fungicides for the reasons described above.

The attached document gives information on wheat growth stages, scouting for diseases, and fungicide efficacy for control of various wheat diseases.

If you have any questions or concerns feel free to contact me.

Hillary L. Mehl, Ph.D.
Assistant Professor of Plant Pathology
Virginia Tech Tidewater AREC
6321 Holland Road
Suffolk, VA 23437
Telephone: (757) 657-6450, ext. 423
email: hlmehl@vt.edu

Additional information: wheat-disease-update-2014-pdf