Don’t Tackle Tar Spot Too Early
Jun 09, 2026
For many plant diseases and pests, you can never be too early. When it comes to tar spot, our increasingly common foe, too early is just a waste of money.
“Spraying for tar spot before tassel might feel good, like you’re in control,” said Kevin Carlson, Federated’s agronomy sales manager, “But it won’t give you the protection later on. You won’t see a return on your investment. It’s really just a waste, and we don’t recommend it.”
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Optimum timing for fungicide is between tassel (VT/R1) to milk (R3), in a single application
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Anything before V10 won’t offer protection of the ear leaf and above, negatively impacting yield
“The main thing for growers to be keeping an eye on from now until tassel is whether we’re seeing moderate temperatures with some rain,” Carlson said. “If it’s really hot and dry, I don’t see tar spot being a major problem. It needs the right conditions, and we don’t know that until game time. So why waste your money?”
If the conditions have been right for tar spot leading into tassel, that’s the time to spray. Federated’s two high clearance sprayers (the “high boys”) are here to help you with that.
“Tar spot is so widespread that we’re starting to call it a common disease,” Carlson said. “But you still can’t control it early with a fungicide. It takes optimum timing to maximize your ROI.”
If you’d like to discuss tar spot control in detail, or to schedule an application with the high-clearance sprayer, contact your Federated Agronomist.