Their presence in flowers at early bloom may result in poor fruit set due to pollination interference by thrips feeding. Field observations indicate that three thrips per flower may interfere with pollination and cause defectively shaped pods. After pods are 1 to 2 inches long, damage is primarily cosmetic since small blisters are generally the only results of their feeding. In the home garden, planting in aluminum foil that has been laid on the bed tends to repel thrips. Insecticidal soaps may give adequate control.
Moths leave field corn when it begins to dry and enter late-planted fields of peas and beans.
The moths lay eggs around the base of emerging plants. These eggs quickly hatch into larvae, which are small, slender caterpillars with green, blue or brown bands around each body segment. The larvae bore into the stalks of young plants near the soil line and tunnel up and down the stalks. A silken tube is usually attached to the entrance hole where the larvae bore into the stem and the larva may sometimes be found in this tube. Plants damaged by lessers become stunted, wither and later die.