Scab Risk for Flowering Wheat Increases across PA

Check your crop’s growth stage and your area’s risk level to prepare for scab infection.

Now that most of Pennsylvania has received measurable rain and remains humid, any wheat that is now flowering is at higher risk for infection by Fusarium head blight (also known as scab).  Mild, wet environmental conditions promote sporulation of the fungus that causes this disease, and these spores can gain access to the grain head when the plant is flowering (in anthesis).  If this happens, the fungus can grow undetected in the kernel and produce mycotoxins, including deoxynivalenol (DON, or vomitoxin).

If your wheat or barley has been experiencing showers or high humidity for a few weeks, consider a fungicide application for scab at early flowering.  If you plan to spray for head scab, choose a labeled triazole-containing product (FRAC 3) like Proline, Prosaro, Prosaro Pro, Miravis Ace, or Sphaerex.  Do not use a product that contains any strobilurin (FRAC 11).  The Miravis Ace label allows for earlier application than other fungicides, but best results are still achieved when application is timed after full heading in barley and flowering in wheat.  If weather conditions prevent fungicide application at ideal timing, an application as soon as conditions allow will still be quite effective in reducing scab and DON production.  Follow labels to determine post-harvest interval constraints for the fungicide you choose. Spray nozzles should be angled at 30 degrees down from horizontal, toward the grain heads, using forward- and backward-mounted nozzles or nozzles with a two-directional spray, such as Twinjet nozzles. Additionally, a fungicide treatment at heading using any of these products will also give you excellent control of most leaf diseases as well.

For wheat that has not yet reached anthesis, continue to check your risk level starting at heading by visiting the Fusarium Risk Tool.