Disease Pressure Low Amid Heat Wave

Heat has dominated the Indiana Farm Forecast for quite some time now. Some crops are handling the heat well while others are not. The good news is that disease pressure has been low to start the season.

“One thing tar spot does not like is heat,” says Dan ‘Corn’ Quinn on the latest Purdue Crop Chat podcast, available now wherever you listen to podcasts. He’s Purdue Extension’s Corn Specialist.

Quinn points to a tool available via the Crop Protection Network that provides crop disease forecasting.

“If you actually look at tar spot risk over the last week, it was pretty high in parts of June, but we really weren’t concerned about it because the crop was still pretty young and not at any stage where we wanted to make any decisions at that point. But the risk has actually kind of plummeted in a lot of areas.”

Quinn says he and Darcy Telenko, Purdue’s Field Crop Pathology Specialist, have received a number of pictures from farmers with what they believe to be tar spot.

“They look like tar spot, but it’s insect poop, insect frass. If you can scratch it off, try and rub it off, then you’ll have insect poop on your hands…but maybe insect poop on your hands is better than having to deal with tar spot.”

Quinn shares what he has seen out in fields.

“I’ve walked a lot of our trials. They’re pretty clean. There’s a lot of common rust out there. Patches we’ve seen here and there. That’s been about the only disease I’ve seen. On the crop risk tool, we are at a higher risk for gray leaf spot, but I haven’t really seen it yet. So, be mindful of that disease. Some of those diseases are kind of second fiddle. They get forgotten about every year, but we have gray leaf spot every year.”

Tune in below to hear more from Quinn and ‘Soybean Shaun’ Casteel in the latest Purdue Crop Chat. You can also find it in the free Hoosier Ag Today mobile app.