The outside few rows looked fine. But there was too much sunlight shining through to be normal. A few rows in, there was a rectangular patch the size of an average farm toolshed where corn was two feet tall. There were only a few ears on any stalks.

"It's deer feeding damage," explains Dennis Bowman, Extension specialist with the University of Illinois. This particular spot happened to be on the Farm Progress Show grounds near Decatur, Ill. There is a large lake nearby and deer are so plentiful they actually carve their own trails from brushy, wooded area out to the fields.

Wow! No corn. This large block just a few rows inside the field border was severely damaged by deer, says Dennis Bowman.

"We've seen this before," he says. "The deer begin feeding early in the season, and keep nibbling as stalks try to regrow. You even see some stalks that try to put an ear where the tassel should be. There usually aren't any kernels on it. Plants are totally disrupted because deer continue feeding on them as the season progresses."

While it may not contribute to a large loss overall on field average, it depends upon the size of the field and the number of spots where deer feed. Where deer damage was worst, such as in this spot, it reminded one of 2012, where yield was 0 to 10 bushels per acre and corn was two to four feet tall because of drought, not deer damage. The end result was the same – no corn to harvest in those spots.

The problem is that if you farm near one of these areas where there is a large population of deer, there is little you can do about it to protect the crop, Bowman says. If it's widespread and severe enough, you may collect crop insurance, particularly in you have revenue-based insurance. Most of the time, though, averaged over the whole field, it may not allow crop insurance to kick in.