Published on Monday, February 18, 2019
Tar Spot is a newer disease in the U.S. that is increasing in its reach and severity. In response to growing concerns about this disease, Beck's product team has rated several of our commercial and experimental hybrids throughout our marketing area (see table below). While these findings are only preliminary since we have not yet had the opportunity to evaluate this disease over multiple years, we feel that this information will provide guidance in situations where there is significant pressure.
FIELD CONDITIONS: Most of what we know about Tar Spot comes from its native Mexico. Cooler weather (between 50 to 70° F), high humidity and prolonged periods with wet leaves seem to be good conditions for the disease to form.
• Small raised black lesions on the leaf that cannot be rubbed off
• May be present on dead or living tissue
• May or may not be surrounded by a tan halo
Tar Spot is one of the many potential yield-limiting factors in corn, but should not be a primary driver in hybrid selection. Until we gain a better understanding of the life cycle of this disease, continue to practice good plant health management. This includes rotating corn away from infected fields, considering tillage to bury residue, and planning to invest in a fungicide. Currently, Delaro®, Trivapro® and Miravis® Neo are labeled for the control of Tar Spot. In general terms, fungicide applications help to slow the infection in some situations. As always, please contact your Beck's product team with any questions.
Author: Craig Moore
Categories: CropTalk, 2019