bark beetles

Creatures no larger than grains of rice imperil the towering ponderosa pines of the Tonto National Forest.

Learn all about bark beetles in a free University of Arizona Cooperative Extension Gila County webinar at 11 a.m., Thursday, Dec. 2, hosted by Christopher Jones, Gila County’s Cooperative Extension Agent with the University of Arizona.

Jones is responsible for a wide array of UA’s agriculture and natural resource programs in Gila County. He conducts extension programming in forest health, watershed, and horticulture education.

In a one-hour presentation, Jones will show photos of bark beetles and the damage they have wrought, and explain best practices for protecting trees from bark beetle attack — prevention such as thinning, irrigating, slash and firewood management, and insecticide treatments.

Lower stand densities and thinning can improve tree growth and vigor and promote greater plant diversity. Supplemental irrigation can reduce drought stress when practical for high value landscape trees. Fresh forest slash and firewood should be managed to minimize bark beetle habitat that may lead to increased localized beetle populations. Registered insecticides can be sprayed onto to trunks to prevent beetle entry. Injection of systemic insecticides and anti-aggregating pheromones are being researched and may have targeted applicability.


The Arizona Department of Forestry and Fire Management aerial surveyed the state in 2018, flying over 15 million acres of forest and assessing 276,000 acres of tree damage from bark beetles. That marked a 513% increase in bark beetle activity.

Drought and bark beetles are to blame. Bark beetles can sense chemicals emitted by stressed, unhealthy trees. Trees that are adequately hydrated produce enough pitch to deter bark beetles and other parasites that try to bore their way in. Worsening drought leads to forest-wide infestation.

The informative online chats are arranged and moderated by Jones. Cooperative Extension’s website has an array of links to programs, talks and resources for Rim Country gardeners.

To be added to Jones’ invite list for winter gardening and horticulture workshop, call 928-402-8586 or email

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