Field Identification
A longhorn beetle that uses black locust as a nursery—yellow-and-black adults mimic wasps on goldenrod in fall while larvae chew heartwood tunnels for years. Stressed street trees snap in ice loads; healthy thickets just host wildlife drama.
Oval exit holes and coarse frass in bark crevices; crown dieback in heavily infested lollipop trees. Adults appear late summer through early autumn on flowers.
How to Deal With It
Organic Control Methods
Sprays barely reach larvae—limit neem or pyrethrin to protecting high-value young trees when adults are mating on trunks, not as a forest-scale fantasy.
Woodpeckers excavate larvae; parasitoids attack smaller cerambycids but are not a silver bullet here—think habitat, not hero product.
Avoid planting Robinia as a specimen where limb failure risks property; diversify street-tree palettes; prune deadwood that concentrates beetles.
Remove and chip badly infested trunks before emergence season; solarize small logs if local regulations allow.
Do not wound trunks; keep trees vigorous with mulch—not volcano mulch—to reduce stress that favors reinvasion.
Let Nature Handle It
Natural Enemies
- Woodpeckers
- Parasitic Wasps (Cerambycidae associates)
Threat Map