Crop Scene Investigation - 59: The white mould mystery in Mike's soybean field

Saturday, January 9, 2016

by BERNARD TOBIN

Unmanned aerial vehicles (UAV) are quickly becoming part of the farming landscape and airspace in Ontario.

Agronomists like DuPont Pioneer sales representative Scott Fife are putting the flying machines to work to grow better crops by targeting nutrient applications and helping to manage disease.

Fife has been sharing his crop scene investigations with Better Farming readers for several years. But this time, instead of taking us into the field to solve a mystery at ground level, he takes us 300 feet above a soybean field just outside Berwick. The accompanying photo was taken on Sept. 1, 2015.

"It's my neighbour Mike's farm and we were trying to determine why there was so much white mould in the right side of the field. You can really notice the brown spots from high above," says Fife. "At ground level, those are high concentrations of white mould." There's no history of mould in the field and in this picture there's no mould in the left of the field, he notes.

The field was planted to corn in 2014. The crop was harvested for grain and there was no tillage performed before Mike planted soybeans on May 15.

There is one key event, however, that readers need to know about. After the snow melted in April, Mike decided to burn some brush near the end of the field. The fire took off and burned the right side of the field before it was contained. "There was a lot of trash in the field and it burnt quickly, but the fire department was able to control it," says Fife.

But the fire didn't change Mike's planting intentions. He no-tilled the beans into two dramatically different environments, explains Fife. "After the fire, half the field was bare while the rest was covered with heavy corn residue."

Mike forgot about the fire as the season progressed. At ground level, plants in the fire area appeared to be doing better than the rest of the field. They were bigger, growthy plants with a denser canopy. Things were good until Mike started noticing the typical symptoms of white mould – stem lesions, wilting, lodging and dying plants.

"That's when we decided to send up the UAV," says Fife. "The picture just confirmed my diagnosis. You can really see the pattern of the fire. Overall, the plants in the burned area were maturing faster and it's obvious that those brown spots indicating the white mould were all in the burned area."

Do you know why the fire-burned area of Mike's soybean field was full of white mould?

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