Host Plants of European Corn Borer
Sweet corn, popcorn, and seed corn are the second most affected plants by ECB, behind field corn. Other crop species that are occasionally infested include, cotton, peppers, snap beans, wheat, and potatoes. Some plants that have been reported to be infested with ECB but cannot host the larva through their lifecycle include 'apples, chrysanthemum, lima bean, soybean, black-eyed pea, small grains, sorghum, tomato, onion, and sage' (Mason et al, 1996).
Damage caused by European corn borer ranges from mild to severe. Since corn is the first choice of a host for the ECB, damage to field corn, sweet corn, popcorn, and seed corn is usually the most severe. The ECB attacks many different areas of the plant. The first generation of ECB attacks the leaves and stalks of the corn plant. ECB larvae leave small holes in the leaves and holes entering the stalk of the plant indicating the beginning of a tunnel. The second generation ECB feed on the leaves, the stalk, the ear, and the bottom portion of the leaves closest to the stalk called the leaf collar and sheath. The third generation continues to feed on the leaf collar and sheath, as well as the ear (Fig. 6a and 6b).
Any of the generations that feed on the corn plant can cause problems both while the plant is growing and during harvest. Feeding on the leaves and the stalk disrupt the biological processes of the plant (Fig. 7).
For example, when the ECB larvae damage the green leaves of the plant, this reduces the plant’s ability to perform photosynthesis. When the stalk of the plant is damaged, this reduces the amount of water and nutrients that can travel through the stalk to the developing ear. Therefore, since the amount of nutrients is reduced, the developing ear cannot reach its full potential, which results in a reduced yield for the producer. European corn borers also feed on the ear shank of the corn plant. Once the ear shank is damaged this increases the probability that the ear will drop to the ground, making it unable to be harvested.
When damage occurs from ECB the plant is also at a higher risk for disease. Injury caused by the ECB, creates an easy location for disease pathogens to enter the plant. In this situation, stalk rot is a common disease to affect corn plants. When disease and damage occur, the stalk weakens and complicates the harvest process. Plants that have become lodged due to disease or damage, are often unable to be harvested and may even make it difficult for equipment to move through the field. Sweet corn, popcorn, and seed corn are affected in much the same way as field corn. Since sweet corn is sold fresh and for canning, ear feeding by ECB is the most damaging. However, in popcorn shank feeding by ECB affects the plants, causing the ears to drop on the ground and decreasing harvestable yields. European corn borer feeding on seed corn plants can directly affect the seed stock for the next growing season by reducing the amount of seed that is produced per plant. Damage that occurs to other types of crops, such as peppers or potatoes, includes boring into the fruit and stalk and laying eggs on the leaves of the plant. This is a problem because the moths will lay their egg masses on other types of plant material. Once these eggs are mature they will hatch and larval feeding causes damage to both the leaves and fruit. The damage on the leaves will reduce the plants ability to grow normally. This can directly affect the production of fruits and vegetables. ECB will also bore into fruit making it unsuitable in the fresh market. Since the European corn borer is a damaging pest, it needs to be controlled to avoid excessive crop damage.