Corn earworm

Corn earworm

Corn earworm (CEW) is native to North and South America and is commonly found wherever corn is grown. Large populations of CEW emerge each year and are estimated to be able to infest at economically damaging levels of up to 35 million acres of corn. Losses in corn can be as high as 50% in sweet corn and range from 1.5% to 16.7% for other corn types.

CEW feeds on a wide range of cultivated and noncultivated crops. Because of its wide host range, it is known by several common names, including cotton bollworm and tomato fruitworm.

Corn earworm geography map

Corn earworm damage

Damage

Larvae feed on leaves, tassels and silks. Small larvae feeding on leaf tissue leave pinhole injury. Larger larvae feeding on leaves may cause severe defoliation. Tassel feeding can affect pollination, as can silk feeding, resulting in poor kernel development.

Larvae also can bore into developing and developed ears, destroying developing kernels. This is particularly important in sweet and seed corn. Injury to ears also can lead to the invasion by fungi, which may lead to the development of mycotoxins like aflatoxin.