Ear Damage in Corn – Birds or Ear Rot?

I’ve received a few photos over the last several weeks asking what is causing ear damage in corn (see photos below).  In both cases, the damage is caused by birds feeding on the ears.


Corn Ear Damage Caused by Birds. 2014. Photo Courtesy of Earl Bargen, Manitoba Agriculture 


Corn Ear Damage Caused by Birds. 2014. Photo Courtesy of Lionel Kaskiw, Manitoba Agriculture

Typical symptoms include missing or damaged kernels on the cobs.  In the first photo, shredded husks is the key symptom in identifying birds as the culprit.  Secondary damage can result from ear rots as kernels eaten by the birds will often turn brown or black once the ear rots begin infecting the damaged tissue.

Birds, especially large flocks, can cause quite a bit of damage. The most damage occurs along field edges or by wooded areas such as bush, but damage can extend throughout an entire field.  Also, it is also not unusual for birds to prefer one hybrid over another, although the reasons are unclear.  Perhaps it can be attributed to birds being able to detect slight differences in kernel maturity or other kernel characteristics between hybrids.  I have seen this with other animal damage, such as racoons, in hybrid performance trials.  Amazingly, the animal can pick out a hybrid within each replicate of the trial without damaging other hybrids.

Submitted by: Pam de Rocquigny, Provincial Cereal Crops Specialist, Manitoba Agriculture

Have a follow-up question?

Check Your Grain Bins Before the New Year to Reduce Spoilage Issues

Most of the grain/oilseeds harvested in Manitoba in 2012 went into the bin very dry, but also very hot (>28C).  Good news for not having to dry the grain in fall, but that doesn’t mean you can forget about the potential risk of spoilage.  There are reports of grain deliveries in December 2012 being slightly heated, or having some other spoilage issues or insect damage.

 As we get colder, a convection cycle starts in the bin, moving the humidity from the  cooling grain downward, into the bin centre and then up to the top of the bin.  During the process, two things can happen that causes spoilage issues. First, at the top of the bin, moisture can condense and accumulate, creating an ideal zone for spoilage and crusting. Second, grain is an insulator and the ‘bin heart’ that is warm with moist air moving in, can continue to heat, forming ‘hotspots’ of heated grain and/or creating ideal conditions for insects.

To avoid this unpleasant discovery, go check the bins before the New Year.  Routine monitoring for symptoms of spoilage (smell, visual signs), checking grain temperature and moisture will help manage the stored grain quality. 

  • Watch for bins that the snow has melted off.
  • Open hatch to check inside. Grain/oilseeds should not smell musty, mouldy or sour and should not have any white or greyish crusting. 
  • Probe the core of the bin and the probe should penetrate the grain easily.  If not, a crust could be forming underneath the top layer of grain or a heated/dense spot may have occurred.

 The practise of taking ‘a load’ out of the bottom of the bin and putting it on top or ‘turning’ the bin is also helpful in moving the layers of grain around in the bin and fracturing the heart to reduce pockets of hot and moist grain.


More information on preventing and managing stored grain insects: http://www.gov.mb.ca/agriculture/crops/cropproduction/faa06s00.html

Grain Drying and Storage of Damp Grain: http://www.gov.mb.ca/agriculture/crops/cropproduction/faa05s00.html

Manitoba Listing of Grain Handling, Storage and Process Technology: http://www.gov.mb.ca/trade/globaltrade/oem/english/grain.html

Have a follow-up question?