Rhododendron: Rhododendron lace bug

• Categories: Ornamentals Rhododendron Rhododendron Insects Shrubs
• Last review date: 2026-08-29 08:37

Biology

The rhododendron lace bug causes stippling on the upper surface of the leaves, and deposits crusty or tar-like excrement on the lower surface.

Adult insects are whitish-tan and approximately 1/8″ long with lacy-looking wings. Nymphs grow to about 1/8″ and are spiny.

Infestations are more severe on plants in the sun. Damage is usually apparent by early to mid-July.

While almost never fatal, repeated infestations of rhododendron lace bugs may result in yellowed, sickly plants. This insect is not found on azaleas.

Rhododendron lace bug has one generation per year. It overwinters as eggs laid on the underside of leaves, usually along leaf veins.

See also Azalea: Azalea lace bug.

Management Options

See "Using Integrated Pest Management (IPM) in the Landscape" for successful problem management techniques.

Non-chemical Management

Select non-chemical management options as your first choice!

• Some spiders and insects such as assassin bugs and minute pirate bugs may help control the population naturally.
• Hand removal of adults and nymphs on a regular basis will limit the amount of visible damage.
• Hosing plants with a strong stream of water directed at the underside of leaves will help to remove them, and wingless nymphs will not return.

Chemical Management

• Apply in spring when nymphs appear. Difficult to control with one application.
• Avoid using Sevin (carbaryl) if there is any possibility of pesticide drifting onto nearby blooming plants.
• These products are toxic to bees.
• Homeowners should not make foliar applications to trees over 10 ft tall.
• Consult a commercial pesticide applicator for treatment of trees and shrubs over 10 ft. tall.

Approved Pesticides

If you choose to use a pesticide, some examples of products that are legal in Washington are listed below. Some products are labeled for just INDOOR or just OUTDOOR use, or may allow both uses. Be sure to choose a product appropriate for your situation. Always read and follow all label directions.

• Safer Brand Neem Oil Concentrate
  Active ingredient: NEEM Oil, Clarified Hydrophobic Extract
  EPA registration number: 70051-2-42697
• Azera Gardening [Organic]
  Active ingredient: azadirachtin, pyrethrins
  EPA registration number: 1021-1872
• This list may not include all products registered for this use.