Identification
Adults of the artichoke plume moth vary in color from buff to brownish buff, with a wing expanse of 3/4 to 1 1/4 inches. Both fore and hind wings are divided into lobes, giving the appearance of several pairs of wings; the hind wings are fringed. Young larvae are pale yellow; older larvae are off white and turn yellow to pink at maturity.
Life Cycle
Female moths lay an average of 245 eggs. Eggs are usually laid singly on the underside of leaves and occasionally on the bud stalk. The freshly deposited eggs are light greenish yellow and turn darker with age.
Larvae hatch and feed externally on leaves of vegetative shoots. After the first molt, larvae start tunneling into the leaf stalk. Some larvae may move toward the leaf petiole or toward the buds and mine the outer bracts. With each subsequent molt, the larvae work their way toward the center of the bud. Larvae undergo four to five instars. When close to pupation, larvae cease feeding and emerge from the feeding site and generally drop to the ground. Pupation generally occurs in plant debris, among folds of dried-up leaves.
There are three to four overlapping generations of the plume moth a year.
Damage
Larvae may chew holes in choke bracts, new stems, and leaves and bore into stem and buds. Larvae may also bore into the crown below the soil surface.
Solutions
Cut all plants down to ground level for 2 or 3 months once a year. Chop and cover cuttings with at least 6 inches of soil. Remove all thistles and related plants. Predaceous nematodes may limit the pest if properly applied, although they are not reliable. Soak replant stumps or apply nematodes when you find plume moth larvae about 1/4 inch in the center of plants. Use a pressurized sprayer to apply a solution of nematodes once a week for three weeks.
