What Is Eating My Corn at Ground Level?

Black Cutworm

• The black cutworm is one of the most harmful of corn pests. It is usually gray with black spots. Identifying the black cutworm by its appearance itself is typically quite difficult, as it resides within the soil and is rarely seen. The corn damage it causes, however, is highly visible. From its soil residence the black cutworm feeds at the base of the corn plant; left unchecked, it will completely cut the plant off from the root system. Damage is usually extensive and can result in the destruction of multiple plants, if not an entire crop. Farmers who do not act are at risk of losing large sums of money. Insecticides are the only way to eliminate the problem.

Sod Webworm

• Corn damage caused by the sod webworm is similar to that caused by the black cutworm, but usually not as extensive. In appearance, it is close to the black cutworm but darker in color, usually completely black with even deeper, darker black spots speckled along the back. The sod webworm stays in the soil around the plant, and resulting corn problems include holes eaten into leaves that lie near the ground level, and the eventual separation of the plant from its root system. You must use an insecticide to manage the sod webworm.

Wireworms

• Corn problems resulting from the wireworm appear in the early stages of the plant's development. Wireworms are found in the soil surrounding the corn, and after planting, when the corn first begins to grow, they begin feeding on the developing root system. Plants that are not killed by wireworm infestations will most likely grow to be deformed and generally unhealthy, with a low yield of corn. Once an infestation has begun, there is little that can be done to halt it. You can, however, apply a chemical treatment to the crop as soon as it is planted to prevent a wireworm problem.

Corn Rootworms

• Unlike other soil worms that cause damage to corn at the ground level, the corn rootworm does not just feed on roots from the soil; it burrows into the root and feeds on it from the inside out. The efficiency of the roots as carriers of vital water, minerals, and nutrients is quickly undermined and the plant begins to die away. The only way to distinguish damage from the corn rootworm from other pests is by looking closely at a portion of the root. If tunnels have been bored through the interior, the corn rootworm is the problem. As a preventive measure, rotate the crop every year. Once corn rootworms have been spotted, use an insecticide.