Rhododendron Insects

Rhododendron Lace Bug

• The rhododendron lace bug (Stephanitus rhododendri) is a small, pale yellow insect growing approximately 1/8 inch as an adult. These insects are primarily seen feeding on the underside of rhododendron leaves. When feeding, rhododendron lace bugs suck on the leaf's juices. As a result, the top side of the rhododendron leaf will have a bronze appearance. Rhododendron lace bug eggs hatch in May, and these insects live for nearly one year.

Rhododendron Borer

• Native throughout the eastern United States, rhododendron borers (Synanthedon rhododendri) are winged pests found primarily on rhododendron plants. Adult rhododendron borers feature steel blue or black abdomens with thin, yellow stripes on top of their abdomens. The wingspan of adult rhododendron borers is about 1/2 inch. Most rhododendron borers hatch from their eggs in May or June and live until the following winter. Rhododendron borer infestations result in the yellowing of rhododendron leaves.

Azalea Bark Scale

• Along with azaleas, flowering cherries and huckleberries, rhododendrons are host plants for the azalea bark scale (Eriococcus azaleas). This insect is native to the United States, Belgium, Russia and Germany. Azalea bark scales are dark red and grow less than 1/2-inch long. Similarly to the rhododendron lace bug, azalea bark scales suck on the juices of rhododendron leaves, which causes discoloration of the plant. Azalea bark scales also emit a sticky liquid, known as “honeydew,” that creates mold on the rhododendron's leaves.

Black Vine Weevil

• The black vine weevil (Otiorynchus sulcatus) is a pest for over 100 plants, including rhododendrons. These insects are not only dangerous to rhododendrons in their adult forms, but larval black vine weevils also feast on rhododendrons. Black vine weevils are found in Europe and North America. Growing approximately 1/4 inch long, adult black vine weevils eat leaves. Larval black vine weevils eat rhododendron roots, which may cause more severe damage than adult weevils.

Rhododendron Whitefly

• Also known as azalea whiteflies, rhododendron whiteflies (Dialeurodes chittendeni) are yellowish insects with wings and a healthy appetite for rhododendron leaves. Unlike most flies, the wings of rhododendron whiteflies cover their entire abdomens. Sooty mold and leaf yellowing are common symptoms of rhododendron whitefly infestations. Rhododendron whiteflies are relatively small insects, growing less than 1/10 inch as adults.