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Tar Spot

Bright green corn leaf with scattered patches of yellowing. There are dark brown-red spots along the central vein.

Other names: Tar Spot of Corn, Phyllacohra maydis

Where did it come from?

Tar spot is a pathogen from Central and South America that was first found in North America in 2015 in Indiana and Illinois.

Why is it invasive?

It produces small raised black spots in leaves and can cause yield loss.


♦ Diseases of Corn: tar spot

♦ Tar spot of corn

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Image credit: Daren Mueller, Iowa State University, Bugwood.org