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Most Crops OK Despite Frost – for Oct. 8, 2009

“That (heat in) September saved us big time when it came to the corn crop.”


Thanks to the warmest September on record, this fall’s first frost Sept. 29 did little or no damage to most Manitoba crops, including later-maturing ones such as corn, soybeans, edible beans and sunflowers.

It didn’t even freeze in many parts of western and northwestern Manitoba, according to data collected by Andy Nadler, Manitoba Agriculture, Food and Rural Initiatives’ (MAFRI) agricultural meteorologist.

For the second year in a row, farmers who grew heat-loving crops beat the odds after a slow start and cooler-than-normal growing conditions. But no crop is safe until it’s in the bin and even then things go awry.

MAFRI and crop insurance staff are now more worried about the impact of extended rain on unharvested crops.

“The first of September we thought it would be a nightmare for corn, absolutely,” said David Van Deynze, manager of claim services for Manitoba Agricultural Services Corp. “That (heat in) September saved us big time when it came to the corn crop. There were hardly any fields that were even close on Sept. 1 and now it turns out just about everyone of them made it.”

Last year, crops caught up due to a warm August. This year the heat hit in September. During the first 15 days of the month more average daily crop heat units (CHU) were recorded in many places than in July.

As of Sept. 27, Gladstone and Morris received 100 per cent of their normal CHU. Carman collected 96 per cent, but Morden and Winkler lagged at 94 and 92 per cent, respectively.

The lateness of the frost also helped save the day both years. Had it come much earlier, it would’ve been disastrous.

Most cereal and canola crops were harvested or in the swath when it froze. With few exceptions those crops were mature enough to be unharmed, Van Deynze said.

“At worst it’s going to hurt quality a little bit, but probably not as much as a week of rain now if it keeps on raining on and off,” he said.


The coldest temperature was -2.89C at Dugald. It froze in most parts of the central region as well as parts of the Interlake and the southeast.

In comparison it was balmy at Gimli where the temperature bottomed out at 5.4C. Russell, Swan River and Dauphin weren’t far behind at 2.95, 4.5 and 4.7C, respectively.

Where there was frost, corn leaves turned a silver-grey colour, but husks and stalks are still green and the plants still growing, said Pam de Rocquigny, MAFRI’s business development manager for feed grains.

“We were on borrowed time as it was,” she said. “The good news is it happened later and that it wasn’t a hard killing frost that may have put some crops in jeopardy, but right now we’re still cruising along.”

Most of Manitoba’s sunflowers were advanced enough to handle the frost, said MAFRI’s oilseed specialist Anastasia Kubinec.

“Now our bigger concern with sunflowers is the head rot issue,” she said. “Last year was a bad year for head rot and this year as well.”

Head rot is caused by sclerotinia, which also caused stem rot in sunflowers this year. Plants infected with head rot drop their seeds,

while stem rot causes plants to break and fall over, making harvest difficult.

Phoma stem rot, which also causes plants to break, has infected some fields too.

Sclerotinia is common in sunflowers now because growers are pushing their rotations, not allowing a big enough gap between when they grow sunflowers and other susceptible crops such as canola or beans, she said.

Some later canola fields may have more green seeds than desirable. Freezing interferes with the enzyme that helps dissipate the chlorophyll that causes green seeds.

Green seeds could be a problem in some soybean and edible bean fields too, said Brian Jack, a MAFRI farm production adviser who works with pulse crops. Most soybean and edible bean fields survived the frost, he said.

Phones were not ringing off the hook at crop insurance offices following the frost, Van Deynze said.

“There has been the odd inquiry here and there – about corn, mostly,” he said. “It has been pretty quiet and a non-event from our perspective.”


Corn harvest is expected to be late again, dragging into November and December. Some farmers are considering leaving their corn out until spring, allowing the cold temperatures to dry it instead of using expensive dryers.

Crop insurance allows it, but doesn’t encourage it, said Doug Wilcox, manager of agronomy and program development.

“It’s potentially a grey area for us because we don’t pay for management-related losses so if you make a management choice to leave it in the field, then in theory we might come back and say the problems that occurred were from leaving (it out over winter) when you didn’t have to,” he said. “But that rarely happens.”

Corn, or any other crop left unharvested over winter, is vulnerable to wildlife predation, as well as breaking down, resulting in yield loss. Corn can also become mouldy and infested with toxins, reducing its quality and value.

Spring harvesting can also result in delayed seeding.

“If we have another wet spring it can come back to bite you,” Wilcox said.

The last two years show that in the absence of a lot of warm weather, a longer growing season can make up for it, de Rocquigny said. She hopes farmers don’t become complacent, and suggests farmers spread the risk by growing some earlier-maturing varieties too.

“We’ve been lucky,” de Rocquigny said. “You might be leaving some yield on the table by picking a lower corn heat unit variety, which are normally a bit lower yielding, but at the same time you’ve got money in the bank in a normal year. Sometimes though no matter what happens, Mother Nature will trump you.” [email protected]

About the author


Allan Dawson

Allan Dawson is a reporter with the Manitoba Co-operator based near Miami, Man. Covering agriculture since 1980, Dawson has spent most of his career with the Co-operator except for several years with Farmers’ Independent Weekly and before that a Morden-Winkler area radio station.



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