The adults feed on stem and leaf tissues of seedling corn plants. Injured corn plants are ragged because of the notched out leaves. If sufficient numbers of southern corn leaf beetle adults are present, seedling corn plants can be killed. Some entomologists have suggested that southern corn leaf beetle injury has often been misdiagnosed as cutworm injury, especially with respect to stem-feeding injury. In addition, they are experts at camouflage, covering their dark brown bodies with small bits of soil.
Adults emerge early in the spring and begin feeding on weed hosts such as cocklebur.
Early-planted fields are at greater risk for potential problems. Corn planted into fields that have been devoted to pasture also may be more susceptible to southern corn leaf beetles. No-till cornfields also may improve the survival of this pest. Adults overwinter beneath soil and plant debris and in clumps of some species of weeds. In the spring, the adults emerge and begin to feed on plants such as cocklebur and early- planted corn.