Tar spot is a new corn disease that’s emerged recently in the U.S.  It’s been common in Latin America for years, but the United States’ first case was only identified in 2015.  Tar spot remained fairly restricted for the first few years.  In 2021, though, it broke out and spread rapidly into new states, taking many farmers by surprise.

Tar spot is caused by a fungus that produces long tan or brown lesions on the leaves. The disease gets its name from the small, raised spots, called stromata, it causes. Because the spots are black, like tar, they gave rise to the name “tar spot of corn.”

Because tar spot lowers yields and forage quality, it needs to be taken seriously.  Unfortunately, it’s also an aggressive disease, developing and spreading quickly.  So it’s vital for farmers and agronomists to know how to recognize it.

And that’s why the University of Kentucky asked us to make a lifelike model of tar spot corn for their plant pathology department.  As their extension office works to help Kentucky’s corn farmers manage tar spot, they also want to prepare the new agronomists heading into the field.  With a lifesize, realistic model to study that shows all the details of tar spot’s symptoms, the students will be better equipped to recognize the disease in real life.