Crop Scene Investigation - 48: Attack of the underground leaf eaters

Thursday, December 5, 2013

'Something is happening in my corn field,' the young farmer told his crop consultant. 'My corn plants are disappearing'

by BERNARD TOBIN

When he picked up the phone on June 15, certified crop consultant Mervyn Erb couldn't believe what Jason, one of his farmer clients, was telling him.

Jason is a progressive young farmer who knows how to get top yields on his farms, says Erb. "He's very tuned in to his fertilizer requirements, soil structure, soil health and cover crops." Three years ago, Jason rented a new farm that had been intensively cash-cropped. When soil tests revealed a miniscule organic matter percentage of 2.7, he hatched a plan to improve the soil and make it more productive.

"Jason never sells the straw after wheat, always plants a cover crop and shoots for big corn yields, so there's always lots of trash going back into the ground," says Erb.

After the 2012 wheat harvest, Jason planted a cover crop that "must have been five feet tall," recalls Erb. "It was a mix of volunteer wheat, oats and yellow tame mustard. He thought it would be great for the soil structure and would really improve the farm. We had a lot of wet weather last fall, but he did manage to plow it down and worked up the field this spring for corn."

On this day, Jason was all business and immediately shared a puzzling development on the new farm. "Something is happening in my corn field," he told Erb. "My corn plants are disappearing." Erb scoffed at the idea, but he quickly realized Jason was serious. The young farmer continued: "There are big holes all over the field. The plants are all buggy-whipped and twisted and they are being pulled back into the ground."

For Erb, "that was the darnedest thing I've ever heard," so he headed to the field to take a look for himself.

"When I pulled up to the field, I could see that the corn wasn't standing up straight, it was leaning sideways. I couldn't believe what I was seeing," recalls Erb, who did some quick plant counts to tabulate the damage. "Out of the 28,000 plants per acre that had emerged, 6,800 of them were bent over and the leaves were being pulled into the ground."

Erb made a mental note of the field conditions – the weather had turned wet and cool since May 11, creating poor growing conditions. "Jason had shorter corn than usual, but it had three or four leaves on it. With the lack of heat, the corn wasn't growing in height, but there were lots of long leaves that were actually touching the ground.

"Any leaves that were near or touching the ground were being grabbed by something and pulled into these holes in the ground. And they were anchored in there pretty good."

When Erb began to pull the leaves out of the ground, he dragged out two to three inches of shredded leaf. "I said to myself, 'What kind of creature in this field is big and strong enough to pull a corn leaf into the ground?'" He ruled out both slugs and centipedes, neither of which was strong enough to take down the leaves.

"There were about four of these holes per square foot and some of them were the size of a dime." Erb thought he might find the culprits at the bottom of the holes. He reached for a trowel and began to dig.

He found the answer to this puzzle three to four inches below the surface. Do you know what attacked Jason's corn? Send your solution to Better Farming at: rirwin@betterfarming.com or by fax to: 613-678-5993.    

Correct answers will be pooled and one winner will be drawn for a chance to win a Wireless Weather Station. The correct answer, along with the reasoning followed to reach it, will appear in the next issue of Better Farming. BF