Your trees have beetles. Now what?

Published: May. 29, 2019 at 5:38 PM AKDT
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On a sunny Wednesday morning in Anchorage's Lower Hillside neighborhood, William Wheatley stands before a tall spruce tree, snaps into climbing spikes, ropes up, and slings a chain saw to his waist.

A telltale brownish red indicates the tree is dead -- killed by beetles. As the climbing foreman for Tall Trees, it's Wheatley's job to fell the branches, treetop, and trunk. Below, other members of the tree crew feed the branches into a chipper.

The landowner has asked that specific sections of the trunk be kept for firewood.

Spruce Bark Beetles have been munching through trees in Southcentral Alaska at alarming rates. In Anchorage, it's caused a backlog for tree companies as requests flood in for assessments, removals and the application of pesticides, an effective deterrent if applied to healthy trees.

Jessie Moan, a pest management technician with the University of Alaska's Cooperative Extension Service, recommends removing infested trees, ideally before adult beetles take flight looking for new hosts. With the beetle's flight season drawing near, time is running out.

Adult beetles generally start emerging in mid-May through June. One goal of removal is to isolate or kill larvae, which will become adults and spread to new trees. That mitigation tactic is most effective in Fall and Winter.

If dead or infested trees are present on your property and you need to prioritize what to remove, Moan recommends choosing trees that pose the greatest safety risk. These are trees that could hurt someone or damage property if they fall.

Signs of a beetle attack include discoloration in the canopy of the tree, pitch tubes on the trunk -- mixtures of sap and sawdust that weep out in a cone-like blob as a beetle enters the tree, and 1/8-inch boreholes -- the holes left when adult beetles exit.

Pesticides can be an effective deterrent against beetle attacks, Moan said Tuesday, but need to be applied before the flight season begins. She recommends and using pesticides on a case-by-case basis.

Mike Post with Tall Trees recommends pesticide application every two years.

Nurturing healthy trees also helps. Plenty of water and fertilization will help build resilience, but does not guarantee resistance, Moan said.

She recommends property owners invest time and energy on caring for trees that are sentimental or that provide sound or visual barriers.

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