Corn Diseases
All Corn Diseases Content
Corn
Nearly one out of every three dollars generated by South Dakota agriculture starts in a corn field. Two of every three rows of corn become ethanol.
Crops
During the growing season, SDSU Extension provides weekly production recommendations.
Corn Diseases in South Dakota Update
Several South Dakota counties have confirmed positive cases of Southern Rust and Tar Spot this growing season. See our latest recommendations for dealing with these diseases before they become a problem.
Are Fungicides Needed On Hail-Damaged Crops?
Recent storms brought rain, severe wind, and hail. With the hail and wind damage that occurred, many growers are wondering if a fungicide application is needed to protect their hail or wind-damaged crops.
Southern Rust Observed in South Dakota Corn Fields
Southern Rust was recently confirmed in South Dakota corn fields. Yield impacts from Southern Rust can be high, so scouting for the disease is highly encouraged to determine if it is present.
Tar Spot Confirmed in South Dakota
Trace amounts of tar spot were recently found in Yankton and Bon Homme counties and are thought to have originated from corn residue instead of windblown spores. This speaks to the importance of crop rotation in the management of this disease.
Be Aware of Fungicide Resistance in Field Crops
A few soybean and corn fields have received or will be receiving a fungicide application this season. We recommend scouting fields treated with fungicides to determine if diseases are controlled as expected or if there are signs of reduced sensitivity.
SDSU Extension to host tar spot webinar
January 24, 2025
Tar spot is a potentially yield-impacting corn disease that was confirmed in 46 of South Dakota’s 66 counties in 2024. The fungus can cling to crop residue over the winter and re-emerge once temperatures rise. It’s most commonly spread in South Dakota by wind-blown spores.
South Dakota Pest Management Guides
The South Dakota Pest Management guides are now available for free. The guides offer recommendations for controlling weeds, insects, and diseases in a variety of South Dakota crops.
South Dakota Tar Spot Update: November 8, 2024
In late October, tar spot was identified on dried field corn being sold for decoration at a big box store in eastern South Dakota. This fungal disease can be identified by the black lesions that are on both sides of the leaf.