Michigan and Wisconsin, resulting in losses of 231 million bushels — far beyond the yield losses caused by other diseases that year. 2 As of this writing in 2025, the reach of tar spot of corn ...

Phyllachora maydis, also known as “tar spot,” first appeared in Indiana and Illinois in 2015. “It’s a very aggressive disease compared to some of the other diseases we deal with like ...

Tar spot continues to be found in Indiana and our first confirmation of southern corn rust happened this week (Figures 1 and 2). I suggest if you have not gotten out and looked for these diseases now ...