In most places, wheat is currently at the flag leaf to head stage of development, and the flowering stage will begin soon. Many wheat growing geographies have received substantial amounts of rainfall in recent days, which can help to ensure a wheat crop worthy of harvest in areas that lack irrigation; however, excessive rainfall can also fuel disease.
Rainfall, friend and foe
Rainfall can create an environment conducive to disease development. Wheat diseases, such as stripe rust, are being reported at low incidence at this time across wheat country, but that may change rapidly if the cool nights predicted are correct.
Given these conditions, and if they match in your area, this could be the right time to apply fungicide to wheat. Studies show that protecting the flag leaf of wheat, triticale, and oats from disease can assure 70 percent or higher of the crops yield potential. It only makes sense to protect yields with a treatment when conditions align for the best chances to protect your crop from a likely pressure.
If your fields are not expressing any disease symptoms at this time then this could be a good opportunity to apply a protective fungicide treatment to wheat. Once fields are showing symptoms, it is likely too late to make a preventative application.
Types of fungicide treatment
A fungicide application at this time in the crop’s growth, and given the conditions, could likely protect a majority of leaves on the plants, which can have a positive impact on final yield. There are many types of wheat and small grain fungicides. Those fungicides that contain a strobilurin, such as azoxystrobin, (Group 11) or a triazole, such as triticonazole, (Group 3) are common choices for wheat growers. A combination of both Group 11 and Group 3 fungicides are commonly used as well.
Be sure to always read and follow the fungicide product’s label use directions.
This information should not be used as a replacement for consulting the applicable product label. Please consult the label for the most complete and up-to-date information about any referenced product. Readers must have a valid applicator license to use restricted use pesticides. Please consult your state department of agriculture for complete rules and regulations on the use of restricted use pesticides as some products require specific record-keeping requirements.
Washington State University http://smallgrains.wsu.edu/disease-resources/foliar-fungal-diseases/stripe-rust/
USDA Weekly Weather Reports https://www.usda.gov/oce/weather/pubs/Weekly/Wwcb/wwcb.pdf
Pesticide Safety Education Program, Oklahoma State University http://pested.okstate.edu/pdf/fungicide%20moa.pdf
University of Nebraska Crop Watch https://cropwatch.unl.edu/2018/wheat-disease-update