European corn borer

European corn borer larvae

European corn borer (ECB) feeds on all above-ground parts of the corn plant. ECB can produce single, double or multiple generations in a single season. First-generation ECB causes whorl damage, while second-generation ECB tunnels through the stalk of corn.

Several universities have published estimates that ECB crop damage in the United States ranges from $1 billion to $2 billion per year due to yield loss and control costs. An average of one ECB cavity per stalk across an entire field can cut yields by 5% in its first generation and an additional 2.5% by the second generation.

 

European corn borer geography map

 

Damage

Larval feeding while corn is still in the whorl stage results in a typical damage pattern called shothole. The larvae begin feeding on one side of the plant and tunnel through all of the leaf tissue to the other side. When the leaves expand, small rows of “buckshot” holes appear in the leaves.

Young larvae also commonly feed on midribs of leaves, resulting in breakage. Third instar and older larvae tunnel into stalks, ears and ear shanks. Tunneling reduces the plant's ability to move nutrients and water, which can affect yield. Tunneling in stalks and ear shanks also frequently results in stalk breakage or ear drop. This can remove the ear from the harvest zone.

European corn borer damage