Corn is a highly valued agricultural commodity and garden crop due to its significant caloric density. The plant provides an attractive food source across its entire growth cycle, from seed to fully ripened ear. Because of this, corn fields and gardens act as primary feeding grounds for a wide array of wildlife. Growers must understand which species are targeting the crop and at what stage of development, as different animals inflict distinct patterns of damage.
Mammals That Target Corn
Raccoons are one of the most common mammalian pests, typically targeting corn when the kernels reach the soft, sweet milk stage of development. These nocturnal feeders will often pull down stalks haphazardly to reach the ears, creating a visible patch of destruction. A key sign of raccoon activity is the husk being peeled back, with the kernels consumed directly from the cob. The abandoned cobs frequently have a muddied appearance from the animal’s paws during the feeding process.
White-tailed deer inflict damage throughout the growing season, beginning with young plants around the V10 to V16 growth stages. During this early phase, deer selectively browse on the new growth, often pulling out the immature tassel from the whorl of leaves. Later, when the ears are in the milk stage, deer feed on the kernels, leaving a jagged or torn appearance on the cobs. This damage pattern is distinct from the cleaner cuts left by small-toothed rodents, as deer only have lower incisors and must tear the plant material.
Smaller rodents, such as squirrels and mice, primarily target the corn seed itself, both when it is first planted and when it is dry and mature. Squirrels will dig up newly planted seeds or focus on chewing into the kernels of ripened ears, typically extracting only the highly nutritious germ, or “heart” of the seed. Mice are also attracted to the high starch content of the kernels, often contaminating or consuming stored grain.
Birds That Consume Corn
Avian species, particularly large flocking birds, inflict damage at two main points in the corn plant’s life cycle. American Crows are notorious for targeting the corn shortly after planting when the seedling emerges. They pull up the young sprout to consume the energy-rich seed kernel attached to the base of the plant. This action leaves small, uprooted plants lying next to a tiny hole in the soil.
Later in the season, blackbirds such as grackles and starlings, along with crows, cause significant damage during the milk and dough stages when the kernels are softest. These birds peck and tear at the husk to reach the developing grain, commonly stripping kernels from the upper portion of the ear. This pecking results in a shredded, exploded appearance at the ear tip, which is a clear indicator of bird feeding. Other birds, including wild turkeys and pigeons, act as scavengers, consuming grain that has been knocked down or dropped onto the ground after a field is harvested.
Insects That Damage Corn
The corn rootworm is a destructive pest whose larvae feed exclusively on the subterranean root system. This larval feeding impairs the plant’s ability to absorb water and nutrients, stunting growth and causing the mature stalk to lose its anchorage. This loss of stability leads to lodging, where the plant falls over, sometimes resulting in a characteristic “goose-necking” bend in the stalk.
The European corn borer is a moth whose larvae tunnel throughout the stalk and ear. The first generation feeds in the whorl, creating rows of small, circular “shot-hole” damage as the leaves unfurl. Later generations bore directly into the stalk and ear shank, weakening the plant and causing the stalk or ear to break off. The presence of sawdust-like excrement, known as frass, near the entry holes indicates this internal tunneling.
The corn earworm is a caterpillar that primarily targets the developing ear, favoring the silk and the kernels at the tip. Larvae feed on the silk first, which can interfere with pollination, before consuming the soft kernels at the end of the cob. Because the larvae are cannibalistic, it is rare to find more than one earworm per ear. Their feeding leaves behind large amounts of wet, brown frass near the ear tip, which signals their presence.