Aphids suck plant juices, and heavy infestations coat the leaves with sticky honeydew. Large aphid populations cause the new growth to be distorted. Use sprays of malathion, Sevin, acephate and rotenone. Aphids can also be dislodged by a high pressure water spray from the garden hose.
Scale insects blend in well with the stems and may not be readily noticed. Infestations can be controlled with dormant oil applied in the spring before growth begins. A less desirable alternative is applications of Sevin or acephate when crawlers are active. The preferred method of control involves regular inspection for early detection of the infestation then spraying with dormant oil.