Purdue University Department of Agronomy

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July 2012
URL: http://www.kingcorn.org/news/timeless/DeerDamage.html

Decapitation of Corn Plants by Deer

R.L. (Bob) Nielsen
Agronomy Dept., Purdue Univ.
West Lafayette, IN 47907-2054
Email address: rnielsen at purdue.edu

White-tailed deer (Odocoileus virginianus) are among the common mammal pests of corn in Indiana. The sight of deer grazing in harvested fields for dropped ears of corn is quite common in the fall, but these animals are also attracted to corn fields at other times of the year and can leave permanently damaged plants in their wake.

Early in the growing season, deer will sometimes feed on the whorls or tops of young plants in mid- to late June (about leaf stage V10 or roughly 30 inches tall) when the immature tassel down in the whorl is 4 to 6 inches long. Rather than actually eat the whorl leaves, the deer are apparently drawn to the succulent, moist immature tassel. The result are decapitated plants whose young whorl leaves have simply been pulled out and (I can only imagine) the tassel somehow chewed out and eaten. The mostly intact whorl leaves are left behind on the ground along with the tell-tale evidence of hoof prints and deer scat. The decapitated plants usually survive and ear development will continue through pollination and on to maturity, though the ears are usually less than full size owing to the fact that most of the photosynthetic leaf area above the ears is missing.

These animals are also attracted to corn fields at about the time kernels reach the milk stage or "roasting ear" stage of development (early to mid-August). The common symptoms resulting from deer feeding on corn at this stage of development are decapitated ears. The ear symptoms are sometimes mistaken for bird damage, but differ because of the distinct appearance of "cut" husks and missing ends of cobs resulting from the deer "chomping" off the ends of the ears. Bird damage (crows, blackbirds, etc) more typically results in shredded ends of husks and barren cob tips.

Fortunately, deer damage to corn is often limited to a few number of rows closest to wooded areas. However, small fields of corn completely surrounded by woodlots or forest areas can sustain significant whole-field damage by deer grazing in mid-August. Deer damage to plants or ears of corn during the grain filling period often encourages disease infection of the damaged plant tissue by common smut (Ustilago maydis) spores. This disease eventually develops into the ugly or beautiful (eyes of the beholder) mass of fungal tissue on damaged plant parts.

Related reading

MacGowan, Brian, Lee Humberg, James Beasley, Travis DeVault, Monica Retamosa and Olin Rhodes, Jr. 2006. Corn and Soybean Crop Depradation by Wildlife. Purdue Univ, http://www.extension.purdue.edu/extmedia/FNR/FNR-265-W.pdf [URL verified July 2012].

White-tailed Deer (Odocoileus virginianus). 2012. Purdue University Wildlife Crop Damage Site. http://www.agriculture.purdue.edu/fnr/cropdamage/wildlife/deer.htm [URL verified July 2012].

Whorl-less plant
Upper whorls laying on ground
Desiccated whorls at base of plants
View down whorl-less void
Immature tassel from V10 plant
Top of decapitated stalks
Elongation of leaf sheaths
Decapitated plants at silking
Decapitated plants near maturity
Chomped ear tip
Chomped ear tip
Chomped ear tip with smut