Larvae are often immobile, and difficult to dislodge, and may be overlooked when cleaning produce. Larvae produce copious quantities of fecal material which also contaminate and stain produce. Host Plants Larvae of this insect feed widely on plants in the family Cruciferae, but occasionally on a few other plant families that contain mustard oils. Commonly attacked are vegetable crops such as broccoli, Brussels sprouts, cabbage, cauliflower, collard, horseradish, kale, and kohlrabi. Also sometimes attacked are flowers such as nasturtium and sweet alyssum, and weeds in the family Cruciferae.
Adults sip nectar from flowers, and are commonly seen feeding at a number of plants.
The imported cabbageworm is subject to numerous predators, parasitoids, and diseases. A. glomeratus is readily observed in the field, searching diligently on foliage for larvae. Dead cabbageworm larvae are often found with clusters of 20 to 30 A. glomeratus cocoons attached. P. rapae GV occurs most commonly under high density conditions, and often among late instar larvae after they have consumed the exterior foliage of plants and are forced into close contact. In the early stages of infection, larvae are inactive and paler in color.