Fungicide applications, along with hybrid selection, crop rotation, and in-season scouting, is part of an integrated management plan for corn diseases. Plots feature either resistant or susceptible hybrids with either a drone-applied fungicide application for tar spot management. Fungicide timing is key for tar spot management. Use the Crop Risk Tool hosted by the Crop Protection Network at https://cropprotectionnetwork.org/crop-disease-forecasting to access the tar spot forecasting model (originally housed on the former Tarspotter mobile application).
More information about Tar spot: this relatively new foliar disease prefers wet weather and moderate temperatures and can progress rapidly under the right conditions. The main signs of tar spot are raised, black spots called stroma that cannot be rubbed off and appear on both upper and lower leaf surfaces. Learn more about how to differentiate tar spot from insect frass (poop) and other diseases by clicking here. In general, fungicides with multiple active ingredients (AI) are more effective against tar spot and should be applied between VT and R3 in a high disease environment (>5% severity).