Corn is a popular staple, but it is highly susceptible to various pests that can significantly hinder its growth and yield. Identifying the specific creature responsible for damage is key to effective management. Understanding these common threats helps gardeners and farmers implement targeted strategies to protect their plants.
Common Insect Pests of Corn
The corn earworm (Helicoverpa zea) is a common pest that targets developing kernels and silk. Larvae chew through silk, interfering with pollination, and then burrow into the ear, feeding on kernels and leaving frass. Damage often appears at the ear tip, where kernels are consumed or scarred.
Cutworms are nocturnal larvae that sever young corn seedlings at or below the soil line. Active during early growth, they can cause entire plants to collapse. Gardeners may find wilted or severed seedlings and sometimes locate the curled larvae near the base of damaged plants during the day.
The European corn borer (Ostrinia nubilalis) tunnels into corn stalks, ears, and tassels. This internal feeding weakens the plant, leading to lodging (the plant falling over) and reduced nutrient flow. Infested ears may show tunnels and frass within the cob and kernels.
Aphids are small, soft-bodied insects that cluster on the undersides of leaves and on young growth, feeding by sucking sap. This feeding can lead to stunted growth, curled or distorted leaves, and the production of a sticky substance known as honeydew. Honeydew can then promote the growth of sooty mold, further impeding photosynthesis.
Mammals and Birds That Damage Corn
Raccoons cause extensive damage to ripening corn ears, often just before harvest. They pull down stalks to access ears, stripping husks and consuming soft kernels. Signs include broken stalks, partially eaten ears, and muddy paw prints around damaged areas.
Deer browse on corn plants, targeting young seedlings and tender leaves. Their feeding results in ragged, torn leaf edges, unlike smaller pests. Large sections can be defoliated, and deer tracks or droppings confirm their involvement.
Squirrels damage corn ears, especially as kernels harden. They gnaw into ears, creating irregular holes and consuming kernels. Evidence includes partially eaten ears left on the stalk or scattered on the ground, often with rodent bite marks.
Birds, like blackbirds and crows, damage corn at various growth stages. During germination, they may pull up young seedlings to eat planted seeds, causing gaps. As ears mature, birds peck kernels, creating shallow holes and exposing the ear to further damage.
Protecting Your Corn Plants
Crop rotation is an effective practice for managing corn pests. Changing the crop type each season disrupts pest life cycles that overwinter in soil or rely on corn. This reduces pest populations naturally.
Good garden sanitation contributes to pest control by removing hiding spots and breeding grounds. Promptly removing plant debris, weeds, and fallen ears after harvest reduces overwintering sites for insects and deters larger animals. A clean environment makes it less inviting for pests.
Encouraging beneficial insects provides a natural defense against corn pests. Ladybugs, lacewings, and parasitic wasps prey on aphids and corn borer larvae, controlling populations. Planting diverse flowering plants nearby attracts and sustains these predators, creating a balanced ecosystem.
Physical barriers protect corn plants from insect and animal pests. Fencing deters deer and raccoons, especially if tall and sturdy. Netting or row covers shield young seedlings from birds and barrier European corn borers and corn earworms during vulnerable stages.
Employing deterrents can also discourage pests from approaching corn plants. Scare devices, such as reflective tape or noisemakers, can temporarily frighten birds away from ripening ears. While not always a long-term solution, rotating these methods can increase their effectiveness.