Agronomy Talk

Agronomy Update

Wheat Threats Due to Cold Weather in Ohio

Published on Thursday, May 12, 2016

The cool, wet weather we have been experiencing has lead to increased concern for various threats to our wheat crops. This article includes my updates on what I have been seeing in wheat fields across Ohio over the past few days.

Head Scab

The increased amount of rain throughout the state mean that the risk for head scab, remains high for wheat that is just beginning to flower. Yesterday, I saw some wheat in southern Ohio that was flowering. The picture below shows what flowering wheat looks like. 

According to the Penn State University’s risk assessment tool for head scab, there is a high risk susceptible varieties that are heading and a moderate to high risk for moderately susceptible varieties. The maps below depict the areas in Ohio with the greatest risk. The red areas have the greatest risk for head scab. The yellow areas have a moderate risk, and green areas have a low risk.


Fungicides including Prosaro® and Caramba® can be used to help reduce the incidence of head scab. Best management practices indicate fungicides should be applied when 50 percent of the heads are flowering. In addition to head scab, fungicides can help with other diseases you may see including stripe rust and Septoria. Click here to view the fungicide efficacy control guide for wheat diseases. This was created by the North Central Regional Committee on Management of Small Grain Diseases. Be sure to reference this if you feel a spray is warranted.

Wheat Stripe Rust

We are starting to see stripe rust enter several wheat fields in southern Ohio. Below are a few pictures from a field near Ashville, Ohio that depict stripe rust symptoms on wheat. The disease has progressed rapidly in some wheat fields due to the cooler temperatures we have been experiencing. Stripe rust thrives during temperatures in the mid-60s, which is exactly where our temperatures have been over the past few weeks. Stripe rust does not progress as rapidly at temperatures over 80 degrees.  


While no variety is immune to stripe rust, there are differences between genetics and their susceptibility to it.Timely, thorough scouting will help to determine if disease pressure is great enough to warrant spraying.

Wheat Spindle Streak

There is another disease that has been found on Ohio wheat and it is a virus called wheat spindle streak. This disease can also cause some yellowing on the leaves, but does not have the orange pustules that wheat stripe rust has. The disease also proliferates with cooler temperatures. Wheat spindle streak is a virus and cannot be controlled by fungicides. Warmer temperatures will stop the spread.


Although I have not seen any armyworms yet, there is still a chance that these may still become a problem. Consider using an insecticide if you decide to use fungicides for head scab or stripe rust. There were some significant captures of armyworm adults at the end of March and early to mid-April that could cause problems as the larvae continue to grow.

The good news is that we have the potential for some very high-yielding wheat this year. We’ve had a lot of fall tillers, very little winter kill, and large head size from what I have seen. The cooler temperatures have also been beneficial as that is when wheat performs best.  

I am excited to see the results of our wheat this year! If you have any questions or concerns don’t hesitate to contact your local seed advisor or dealer!





Prosaro® is a registered trademark of Bayer. Caramba® is a registered trademark of BASF. 

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Mark Apelt

Mark Apelt

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