BWA (Adelges piceae)

PDF version of BWA - Facts at a Glance (including photos)

Where found: Europe

Host plants: All true firs - Fraser fir is one of the most susceptible

Symptoms: Crooked tops; stiff and brittle trunk - dead branches; gouting; red reaction wood which is harder than normal wood

Important cultural practices:

• BWA is only found on true firs. Remove any large, untreated firs near fields.
• Don't interplant

Scouting: Examine trees with crooked tops for white wool on trunk and under branch/trunk union. Confirm with handlens that is insect and not lichen or resin. Rub finger across woolly masses to find purple stain from living insects. Push on trunk to determine if it is stiff.Life cycle:

• How overwinters: Nymphs on bark and buds
• Number of generations per year: 2 to 4 depending on season and elevation. Once crawler settles at a feeding site, the insect will not move again.

Control considerations: Once BWA is found, you have until the next bud break to get control. There are no effective biological control agents.

• Cull heavily infested trees.
• Butt-prune trees for better coverage.
• Thorough coverage is required for control. Treat trees from opposite directions with a high-pressure sprayer.
• Some pesticides such as horticultural oil and insecticidal soap will not kill all the eggs. Only use these products in the winter when only nymphs are present.