How to Identify an Infestation
Active (beetles inside): pitch tubes (popcorn-shaped resin balls on bark), frass (reddish-brown sawdust at base).
Past (beetles gone): brown needles — beetles already moved on to the next green tree.
During drought: fewer pitch tubes form — look harder for frass at the base of the trunk.
Treatment Options
Pheromones
Anti-aggregation (verbenone) pushes beetles away; aggregation pulls them to trap trees. Push-pull strategy combines both. Apply by end of June. Packets last ~90 days. Works best neighborhood-wide.
Pesticides (Boulder County)
Carbaryl, Bifenthrin, Permethrin. Must be applied by a licensed applicator. Limit to 5–10 high-value trees. Apply before July. No spraying within 35 feet of water. Annual re-application required. Carbaryl detected in Boulder's water supply from upstream spraying — pheromones preferred near waterways.
Forest Thinning (ICO)
Individuals, Clumps, Openings — diverse age/species structure resists both beetle and fire. Remove ladder fuels. Best at neighborhood scale.
Natural & Holistic Methods
Beauveria bassiana fungus
Naturally infects and kills MPB. A 2023 UBC study confirmed strong virulence in field experiments. A 2024 Alberta dissertation completed the first in-natura field trials. Not yet commercially available — in active research. Ward/Left Hand Canyon area is an ideal field trial candidate.
Contact: jennifer.klutsch@nrcan-rncan.gc.ca
Neem (azadirachtin) trunk injection
Reduces brood by 77–87%. Bark spray does not work — must be injected. Low mammalian toxicity.
Natural predators
Woodpeckers, clerid beetles, parasitoid wasps. Effective at low population levels only.
Tree vigor
Supplemental irrigation during drought boosts resin production and natural resistance.
Pheromone Vendor Guide
Colorado-local first
Forestry Distributing
Longmont, CO · 303-747-6414 · forestrydistributing.com
Carries Synergy + ISCA · ~$7.95–$8.00/pouch · Local pickup available — closest to Ward.
BeetleBlock / EcoGreenWarehouse
Westminster, CO · 720-381-1682 · ecogreenwarehouse.com
6.75g pouches ~$10.20 each · back in stock early 2027.
Alpine Tree Services
Summit County · (970) 389-4964
Bulk pricing + professional installation.
National
Synergy Semiochemicals
Original manufacturer. Order early — supply chain issues.
ISCA Technologies
7g extended release · via shop4verbenone.com · 512-282-3003
Tip: Order by May. Freeze extras in a Ziploc — viable next season.
Action Plan
Before end of June each year
- Walk your property — check for pitch tubes and frass on all pines
- Order and deploy verbenone pouches
- Remove actively infested green trees before July
- Contact Colorado State Forest Service for a free property assessment
Annual
Repeat pheromones, apply ICO principles when thinning, coordinate with neighbors for grant access.
Key Takeaways
- This infestation will keep moving up the canyon — manage it, don't expect to stop it entirely.
- Pheromones require neighborhood-wide participation to be effective.
- The window is before July every year.
- Healthy diverse forests resist both beetle and fire.
- Colorado State Forest Service = free resource most people don't know about.
- Community coordination unlocks grant funding individuals can't access alone.