Azalea: Root weevils

Biology

Characteristic damage includes notching of leaf edges by adults and minor to severe root and bark damage by larvae. Azaleas generally have less severe leaf notching than rhododendrons, but may be damaged or killed by root weevils feeding on lower stems and roots. Occasionally the trunk is girdled at or just below the soil surface. Adults are wingless and begin feeding around June to August, depending on the species.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Hand-pick and kill night-feeding adults.
• Apply beneficial nematodes which kill the larvae. They are used as a soil drench in moist soils over 52 F (late summer to early fall in western Washington). Read and follow the label directions carefully.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• Apply when first signs of notching on new leaves are noticed.
• Monthly applications may be needed if infestation is heavy.
• Cease when first hard frost occurs in late fall/early winter.
• Night applications are more effective.
• Beneficial nematodes can be ordered through certain nurseries. They can be applied to control the larval stage if soil temperatures are warmer than 52 F.
• Do not apply nematodes in direct sunlight and make sure the soil is saturated with water prior to application.

Approved Pesticides

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

• Safer Brand BioNEEM Multi-Purpose Insecticide and Repellent Concentrate [Organic]
  Active ingredient: azadirachtin [EPA registration number: 70051-6-42697]
• This list may not include all products registered for this use.

Additional Images