Reports of tar spot have come early this year with confirmed infections in Iowa, Indiana and Kansas. Producers should start scouting fields now to determine which fields may be affected.

Once tar spot has been identified, farmers need to use patience. Fungicide treatments need to be timed appropriately. Purdue University Plant Pathologist Darcy Telenko advised that spraying before V8 will not provide the upper canopy protection later in the season. The optimum time to apply fungicides for tar spot is between tassel (VT) to milk (R3).

Telenko advises to scout fields now for evidence of the disease so fungicide is ready to be applied when the timing is right. If the producer waits too long, the disease can take hold in the upper canopy. At this point, fungicide application may be too late.

Read more about scouting for tar spot here.