Ponderosa Pines in the Prescott National Forest have been susceptible to infestation from bark beetles, killing thousands of acres. Bark beetles are also infesting private property and local residences.
Do you have Ponderosa Pines on your property?
You should know about pine bark beetles. Here is some information that may be helpful:
- Bark Beetles are Native to Arizona, and are always present, in low numbers. They infest ponderosa pines that are prevalent at higher elevations around Prescott.
- The drought conditions have compromised the tree’s vigor by decreasing their ability to fend off colonization by “pitching out” colonizing beetles.
- Infrequent irrigation could slowly restore vigor to uncolonized trees. It is difficult to know exactly where a given tree’s roots are located, but irrigation at the dripline (vertical projection of the canopy) is the best we can recommend.
- Use a soaker hose to apply water at the dripline of the tree and try for a depth of 18”. A steel rod can be used as an irrigation probe. Irrigation can be repeated about every 14 days until natural precipitation moistens the soil to that depth.
- Of the insecticide treatments recommended, the Ememectin Benzoate treatments are more widely available and effective. Several area arborists can assist with this treatment. The carbaryl and permethrin spray treatments are similarly effective, but require specialized formulations of these insecticides and must be applied to the entire trunk up to a 4” top.
Infestation and Removal
- If a tree is infested on private property, it is the responsibility of the property owner to remove the infested tree property.
- Once a tree has been completely colonized, it is dead. Some trees have only been colonized on the upper portions. In these cases, the remaining lower portion of the tree may survive, but the dead top will invite rot organisms and the tree may succumb to these.
- Remove dead trees as quickly as possible. Ips bark beetles can fly over 2 miles, but often seek nearby trees to colonize after leaving the previous trees.
- Have removed beetle-killed trees hauled away to a non-ponderosa pine area if possible. This will decrease the potential of them colonizing nearby trees as they emerge.
- Do not retain slash piles or chip the material from colonized trees. Slash piles provide refuge to bark beetles and pine chips are an attractant to beetles which could then colonize nearby trees.
- The Arizona Department of Forestry has a cost sharing program available for private property owners who need to remove infested trees. Here is a LINK for that program.