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Long silks may be bad news

A farmer once told me what a bad day felt like. The PTO went out on the tractor running the auger, the engine blew in the tractor running the grinder, and a bin fan belt chewed itself up — all before 7 a.m.“Now that’s a bad day — I just went home and started over,” the farmer says. “It turned out to be an expensive day, too.”

That’s how you may feel if you wind up in a hot, dry pocket and find early-planted corn growing silks, but little else. It may turn out to be an expensive year.

Members of the Indiana Certified Crop Adviser panel that provides answers for Crops Corner explain what can happen.

“Corn silks will continue to grow if they haven’t been pollinated,” says Bryan Overstreet, CCA and Extension educator in Jasper and Pulaski counties. “Due to hot and dry weather, your corn pollen didn’t fall while the silks were present. Or it’s possible pollen was killed. If the pollen’s already been shed, there’s little that you can do.”

Steve Dlugosz, CCA, a crops consultant for Harvestland Co-op in eastern Indiana, says it sounds like male and female portions of plants missed the “nick.” “Due to natural variability, the whole field usually sheds pollen for up to two weeks,” he notes. Individual tassels generally shed pollen for two to three days before silks emerge, and then for about seven days.

“Silks can emerge late on some plants, due to extreme stress, possibly missing this extended period of pollen shed. There’s not much anyone can do about it,” Dlugosz says.

Better news

Betsy Bower, CCA, agronomist with Ceres Solutions, Terre Haute, says that with genetic improvements of more drought-resistant hybrids, silk growth is more robust. That’s especially true if it’s not dry. Bob Nielsen at Purdue University reported finding abnormally long silks last year under cool, moist conditions.

“The abnormally long silks could be due to the hybrid,” Bower says. “In extreme cases it could be caused by missing the nick between pollen shed and silk emergence. Tassel emergence and pollen shed take precedence over silk elongation when resources are limited. In severely dry conditions, plants may have enough reserves for tassels to emerge and pollen to shed, but not enough reserves for silks to elongate.

“With improved genetics missing the nick is very uncommon,” she says.


Shake and bake: You’re cooking if the silks fall off the ear. If they remain attached, the ear isn’t fertilized.

Try ‘shake test’ for pollination

Elongated silk growth doesn’t always mean that silks didn’t get pollinated with today’s newer hybrids, notes Betsy Bower, Terre Haute. She suggests doing a pollination test before you panic and conclude pollen came out and disappeared before silks emerged, all due to weather stress.

Bob Nielsen of Purdue University has perfected what he calls the “shake test” to determine pollination. Bryan Overstreet, an Extension ag educator in Jasper and Pulaski counties, explains: “Remove husks and gently shake the ear. Silks will break off from pollinated kernels.”

If silks remain attached to the ears, that’s when you’re in jeopardy of having a very bad day. It usually means ovules weren’t fertilized.

That can happen if pollen was long gone when silks emerged.

This article published in the July, 2010 edition of INDIANA PRAIRIE FARMER.

All rights reserved. Copyright Farm Progress Cos. 2010.