What is in this article?:
- Itâ€™s time to scout wheat for diseases
- Continue scouting through flowering
• The decision to apply a fungicide to wheat should be based upon multiple factors including: 1) disease presence, 2) fertility and yield potential, 3) weather conditions and 4) cropping history.
Continue scouting through flowering
Disease scouting in wheat should be continued through the beginning of flowering, because even if a fungicide at the flag leaf growth stage is not recommended, a fungicide application during a boot growth stage (Feekes 10.0-10.5.1) may be warranted to protect the flag leaf and the head from disease.
A detailed foliar fungicide point system can be found at UTCrops.com (Wheat Foliar Fungicide Point System) that can be used as a guide to determine the need for a fungicide application.
Another critical time for fungicide application is at mid-bloom (Feekes 10.5.1) which would protect wheat from Fusarium Head Blight/Scab/Head Scab.
Head Scab can be more severe in wheat planted behind corn that has high nitrogen levels, which fits the description of a lot of wheat fields in Tennessee.
For scab to occur, rain events during flowering are necessary and while we don’t regularly experience a lot of Head Scab the risk varies from year to year.
A forecasting tool is available at www.wheatscab.psu.edu, which will have commentary for Tennessee as the wheat gets closer to flowering.
There are multiple fungicides labeled for wheat and for the control of different diseases. The North Central Regional Committee on Management of Small Grain Diseases (NCERA-184) has developed information on fungicide efficacy for control of certain wheat diseases.
This information can be found at UTCrops.com (Wheat Fungicide Table – NCERA 184).
Application coverage is also important and applications should be made in at least 5 gallons of water per acre by airplane or at least 15 gallons of water per acre by ground application.
Common foliar wheat diseases in Tennessee include: Glume (Stagonospora) Blotch, Septoria Blotch, Leaf Rust, Stripe Rust; and less common include: Powdery Mildew and Fusarium Head Blight (Scab).
While there has been little to talk about regarding wheat diseases in Tennessee this season, that is not the case in our neighboring states. Both Mississippi and Arkansas have reports of stripe rust, with severe levels in some fields.
To my knowledge, there has only been one report in Tennessee of stripe rust in Haywood county, on a single leaf, but with the wet, cool weather we have had and the presence of the disease in our neighboring states there is an increased risk, so please be on the lookout.
If you have any fields you suspect have stripe rust or other diseases and would like assistance please contact your local county Extension office or myself (firstname.lastname@example.org 731-425-4713).