Plants thus affected may have normal appearing leaves on the outside of the plant but have a ball of undifferentiated tissue in the center near the base, which will not form new leaves or artichoke buds. On older plants, larvae feed on leaves and bracts of floral heads. Feeding on leaves is usually not economically damaging, but feeding on bracts will result in culled heads. Some pupae may be affected by discing as well. Beet armyworm eggs and larvae are often easier to find on weeds in and near the field than in the artichoke plant.
Populations can build rapidly, so check fields twice a week.
Monitor adults with pheromone traps placed along the edges of fields. This is a particularly good technique for detecting large emergences or migrations occurring on weather fronts. Treat when fresh frass is observed in a significant number of plants. The following materials are listed in order of usefulness in an IPM program, taking into account efficacy and impact on natural enemies. Do not apply within this many days of harvest.