Abnormal Corn Ears

August 25, 2015 10:12 AM

Are you seeing some unusual ears in your corn fields? Diagnose what went wrong by comparing your cobs to the ones below, and then develop a strategy to fix the issues.  


beer_bottle_ear_cornEar Pinching

Beer Bottle Ears

Symptoms: Kernel row numbers may decrease by half from bottom to top of ear (for example, from 16 to eight kernel rows per ear). The ear length is usually about normal.

Causes: Severe stress during the seven- to 10-leaf collar stages and late application of sulfonylurea herbicide.


beercanBlunt Ear Syndrome

Beer Can Ears, Ear Stunting

Symptoms: Markedly reduced ear size and kernel numbers per row. Husk length and kernel row number may be normal.

Causes: Unknown but is most often associated with low temperature stress during early ear formation.


multiple_earMultiple Ear Syndrome

Bouquet Ears

Symptoms: Multiple ears on the same ear shank—sometimes five or six ears form a “bouquet.” Side ears may or may not be fully developed.

Causes: Unknown but similar to blunt ear syndrome.


nubbins-1Drought- Damaged Ears

Nubbin Ears

Symptoms: Small, misshaped ears with poor kernel set at ear tip.

Causes: Severe drought and other stresses, such as nitrogen deficiency and high plant population.


tassel_ear_2Tassel Ears

Symptoms: Combination of tassel and ear in the same structure.

Causes: Injury to growing point, early-season compaction and saturated soil along field edges. 



corndiplodiaearrot2Diplodia Ear Rot

Symptoms: Partial or entire ear rotted by a white mold growing between the kernels; later the white mold changes to a grayish-brown growth over the husks and kernels. The entire ear may be shrunken.

Causes: Stenocarpella maydis fungus.


poor_kernel_setHi-resPoor, Incomplete Kernel Set

Symptoms: Poor reduced kernel set.

Causes: Similar to poor pollination at ear tip. (see next).


poor_tip_cornPoor Pollination At Ear Tip

Symptoms: Cob tissue without kernels on last 1" or more of ear tip.

Causes: May result from drought, heat, insect damage, herbicides and phosphorus shortage.



TipdiebackcloseupHi-resTip Dieback

Symptoms: Poor tip fill or unfilled ear tips and kernel abortion at tip end of ear at blister and milk stages. 

Causes: Stress during early kernel development, including severe drought, heat, nitrogen deficiency, foliar diseases and cloudy weather.



zipper_earHi-resZipper Ears

Banana Ears

Symptoms: Missing kernel rows on outside or underside. 

Causes: Unknown, but linked with stress after pollination.



chaffy_earChaffy Ears

Symptoms: Lightweight, poorly-filled ears with shrunken kernels and spaces between kernels. 

Causes: Severe photosynthetic stress from the dough through 
early dent stages.


overviewHi-resWestern Bean Cutworm Ear Injury

Symptoms: Scattered patches of partial or complete kernel destruction; often associated with mold growth on affected kernels.

Causes: Kernel feeding by Western bean cutworm.



overviewHi-resBird Damage

Symptoms: Lightweight, weathered ears with damaged, discolored and moldy kernels; often associated with kernel sprouting.

Causes: Poor husk coverage at maturity, and upright ear orientation allows birds to feed on tip kernels.



kernel_red_streakKernel Red Streak 

Symptoms: Red streaks on sides of kernels, extending over the crown. Usually limited to kernels at tip of ear. 

Causes: Toxin secreted during feeding by the wheat curl mite.


SOURCE: Peter Thomison and Allen Geyer, Ohio State University. This is a condensed version of a poster designed by agronomists at Ohio State University. To order a full-size 26”x 33” version, with more detailed text, for $10 plus shipping, call (614) 292-1607 or send an email to pubs@ag.osu.edu. Ask for Poster ACE-1. 

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Spell Check

roachdale, IN
8/28/2015 10:33 PM

  old farmer, it isn't uncommon to have the last inch of the ear not filled out and still have a very high yield. in 2010 I had a field that yielded 246 bpa and every ear was missing grain on the last inch of the cob, I think the plant simply maxed out and ran out of nitrogen. if the last inch would have been filled the field would have yielded in the 280 bpa range. 235 is quite possible, even this year.

Old farmer
Worthington, MN
8/26/2015 10:20 PM

  Not filled to the tip must not affect yield as I saw post from Martin County Mn. with 3 ears not filled to tip and he was claiming 235 B.P.A.--Awesome!!

Chappell, NE
8/26/2015 08:43 AM

  These are below the cost of production ears. You get what you pay for, remember?


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