Author: Eric Day, Virginia Tech
Most species of juniper are attacked.
Description of Damage
Large brown patches scattered throughout the plant are apparent from a distance. Close examination shows masses of brown needles webbed together and pulled in toward the twigs. When pulled apart, larvae can be found within the webbing and dead needles.
Larvae are about 12 mm long when fully developed. They are brown with longitudinal reddish brown stripes. The adults are not often seen, but are light brown and almost 12 mm long.
Where one generation occurs, moths occur during late June and July; when there are two, adults may occur in May and June and again in July and early August. Eggs are laid on the foliage and hatch shortly afterward. Larvae feed for a few to several weeks, pupating in the webs. The winter is spent as young larvae in the webs. It is likely that one generation occurs in Virginia. Most larval development occurs in the spring and early summer, but youngest larvae are present in late July and August until the following spring.
Insecticides can be applied in the spring, but the best time is in late July or early august. Sprays are most effective against young larvae in late July and August, but can be applied in April and early May. Strong spray streams should be directed into the webbing to provide maximum penetration.
This pest has not been reported as common in the state, but does occur throughout Virginia. If heavy populations build up, it can be a serious pest. Apply control measures when evidence of infestation is first noted.