I have recently looked at many corn fields and in general, they look really good! I have started to see a little common corn rust across the region. Although I have not found other foliar fungal diseases, like Eyespot, Gray Leaf Spot, Northern Corn Leaf Blight or Northern Corn Leaf Spot, these fungal diseases can come along through tasseling and grain fill, and I expect them to appear.
- Fungicides are registered through R2 growth stage and may provide an economic benefit from disease control and reduced plant stress! Stratego YLD, Quilt Xcel, Headline AMP and others are all registered and ready to go!
- Fungicides can improve corn yield by extending time for grain fill, protecting crop from a wide range of diseases, increasing water use efficiency, increasing CO2 assimilation and nutrient conversion, improving growth efficiency, and improving the plant’s tolerance to stress. Even in the absence of widespread disease, this can lead to larger cobs, more fully filled ears, and improved stalk strength. Stalk strength will lead to better harvest efficiency. Stalk strength may be critical if the variable growth stage follows through to variable maturity dates!
- Fungicides are compatible with insecticides if needed. You may want to remove any adjuvant in this case.
I have seen a couple other corn diseases- striking diseases, but nothing that can be managed at this stage. The first is CORN SMUT, but unlike “normal”, this has been found on FOLIAGE rather than ears or tassels. See the photos below.
The other disease is GOSS’S WILT, a bacterial disease. I found Goss’s Wilt in several fields in northern Brown County. Management of Goss’s Wilt is through variety selection, rotation and cultural management. That said, keeping plants healthy can possibly affect disease progress. Protecting reproductive tissue and upper leavesfrom fungal diseases like smut, leaf rust, etc. is critical, and foliar fungicides are the tool.