Spirea aphid causes leaf curling and is usually found on the shoot tips or in flower clusters. Heavy infestations reduce the amount of growth produced by the plant. Use sprays of Sevin, acephate, malathion or rotenone. The insects can be dislodged with high pressure water spray from the garden hose.
Oblique-banded leaf roller rolls and webs the leaves together. Hand pick infested leaves or spray with acephate or Sevin.
Inspect the stems of unhealthy-looking shrubs for scales. Use sprays of dormant oil in the spring to minimize injury to predators that help control scales. Crawlers are controlled with sprays of acephate or Sevin. Identify the scale to properly time crawler sprays. The preferred method of control involves regular inspection for early detection of the infestation then spraying with dormant oil.