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Hoosier Bug Beat: Silk-clipping insects in corn deserve your attention.

Tom Bechman 1, Editor, Indiana Prairie Farm

May 26, 2016

3 Min Read

The TV show “Dirty Jobs” put host Mike Rowe in all kinds of nasty situations. He never found his way to a cornfield at tasseling time — but if writers had stumbled across how uncomfortable it is to walk cornfields with corn over the person’s head at tasseling, he might well have found himself shooting a show in a cornfield.

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What would he have been doing there? He could have scouted corn for several things, including which insects were present, and whether or not they were clipping silks. This is the time of year when you read about Japanese beetles and corn rootworm beetles clipping silks. Can enough clipping occur to affect yields? Is it really worth playing the Mike Rowe-role and heading into your cornfields?

The Indiana Certified Crop Advisers panel examines this question. Panel members include Jamie Bultemeier, Great Lakes A&L Labs, Fort Wayne; Gene Flaningam, Flaningam Ag Consulting LLC, Vincennes; and Bryan Overstreet, Purdue University Extension ag educator, Jasper County.

Bultemeier: Severe Japanese beetle silk clipping can have a negative impact on corn pollination. If silks are clipped back to less than one-half inch from the husk, with more than 50% pollination to go and beetles are still actively feeding, it is time to treat.

Flaningam: Damage caused by Japanese beetles needs to be reviewed on a field-by-field basis. Usually, silk clipping will start along grassy field borders and grass waterways. Scout these primary areas first. Each field will need to be scouted for pollen shed. Shake 25 plants and determine the amount of pollen left in the field.

Overstreet: Since Japanese beetles feed in clusters along the edges of fields, it may look worse than it really is. Scout five areas in the field that are not along the edges. The economic threshold is when silks are clipped to less than one-half inch, less than 50% of pollination is complete and beetles are still present.

Bultemeier: Silks grow at a rapid rate. A few clipped silks is not a big issue. But if beetles completely remove silks and prevent pollination, yield impacts could be sizable. This assumes there is feeding across a large portion of the field.

Overstreet: I’ve found you get a better reading of silk length if you scout fields in the morning. Silks will grow at night, and beetles will feed on them during the day.

Flaningam: Check silks to see if they are still viable for pollination. Brown silks should be considered pollinated. Fresh silks still have the potential for pollination. Measure the length of clipped silks. Count the average number of beetles per plant.

Overstreet: To check for percentage of pollination, shuck the ear and shake it to see which silks fall off. Once a silk has pollinated a kernel, it will usually fall off the cob when shaken. Bob Nielsen, the Purdue University Extension corn specialist, has demonstrated this shaking method to help assess pollination to hundreds of farmers and agronomists across the state. From this easy test, you can see how much of the ear is pollinated. For more information on silk clipping and Japanese beetles, you can visit this website: https://extension.entm.purdue.edu/fieldcropsipm/insects/corn-japanese-beetles.php.

About the Author(s)

Tom Bechman 1

Editor, Indiana Prairie Farm

Tom Bechman is an important cog in the Farm Progress machinery. In addition to serving as editor of Indiana Prairie Farmer, Tom is nationally known for his coverage of Midwest agronomy, conservation, no-till farming, farm management, farm safety, high-tech farming and personal property tax relief. His byline appears monthly in many of the 18 state and regional farm magazines published by Farm Progress.

"I consider it my responsibility and opportunity as a farm magazine editor to supply useful information that will help today's farm families survive and thrive," the veteran editor says.

Tom graduated from Whiteland (Ind.) High School, earned his B.S. in animal science and agricultural education from Purdue University in 1975 and an M.S. in dairy nutrition two years later. He first joined the magazine as a field editor in 1981 after four years as a vocational agriculture teacher.

Tom enjoys interacting with farm families, university specialists and industry leaders, gathering and sifting through loads of information available in agriculture today. "Whenever I find a new idea or a new thought that could either improve someone's life or their income, I consider it a personal challenge to discover how to present it in the most useful form, " he says.

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