HEYWORTH, Ill. (WCIA) — Every farmer who grew corn this year was worried about their yield being decimated by the tar spot fungus. This comes after some farmers lost 50% of their crop last year. In response, fungicides were applied on the ground and by crop duster.

So what happened?

Since tar spot needs a lot of moisture, it’s been a no-show this year in much east central Illinois. Ken Ferrie of Crop Tech Consulting at Heyworth, summed it all up this way:

“So last year taught us a lesson quick right here in this area of central Illinois; we kind of call it Tar Spot Alley,” Ferrie said. “It was crushing. We had two 500-year rain events 19 days apart. That set up the environment that brought tars pot in here June 30. We even sprayed and we saw some issues where we got hit 50-bushel and a lot of downed corn with it. It’s a disease that’s got our attention now.

But we have to manage it. How do we do that in the best way we can?

“We teach our customers that we start one leaf below the ear and we go up when we are scouting for disease this time of year and we worry about the top of the plant. That is the most valuable real estate we want to protect,” Ferrie responded. “Tar spot changes that. Tar spot that comes from the residue from previous years will start at the bottom and work its way up, so we’ve got to look down at the bottom. Now all our diseases, for the most part, start at the bottom except for southern rust and things like that. But our other diseases just do some real estate damage to the leaf, the chlorophyll production and stuff.”

“Tar spot has parasitic properties; it actually feeds on the plant. So it takes water and nutrients from the plant, its like having spider mites or aphids down there at the bottom and tar spot at the bottom will bring the plant down,” Ferrie continued. “So when we do see that tar spot, if its homegrown, its at the bottom of the plant. If it blew in from the neighbor, its at the top. And when we see it down in that ear zone, we have to change how we apply our fungicide and we got to drive that fungicide down into that zone to dry to slow it down.

With later corn planting this year, Ferrie suggests fungicide applications may be important later.

“If you didn’t have tar spot at this stage, but you are worried about tar spot, I am probably going to drag my feet another couple of weeks to make that application,” Ferrie said. “Or make two applications. Make an application now and make another at R-3. The back end of the crop is what we have to pay attention to. And unlike other diseases, we found out last year that tar spot can kill it. We had a lot of dead corn here in mid-August last year.”