Friday, April 24, 2009

Bug infects local evergreens

Pest will destroy tree if not treated

Express Staff Writer

Arborist Bill Josey holds a pine branch infected by pine needle scale (the white dots).

Evergreens in the Wood River Valley are suffering from yet another pest: pine needle scale.

"Pine needle scale is widespread here in the Wood River Valley," said arborist Bill Josey, owner of Arbor Care Resources Inc. "It is especially bad in the older, more established neighborhoods like Hulen Meadows, the Sun Valley Fairways and Elkhorn."

Scales are small insects that suck water and nutrients from the needles of evergreen trees, causing the needles to turn brown and die. They can be identified as small white dots (scales) that attach to the needles.

Scales hibernate during the winter under a protective eggshell. Between late May and mid-June the eggs hatch, resulting in active crawlers. During this time the scales' movement increases drastically, spreading from branch to branch and tree to tree. While the male crawlers die off, female crawlers survive. In late summer, they typically lay as many as 40 to 100 eggs per scale.

Josey said pine needle scale has worsened recently as the scale has gone unnoticed and untreated for years while the insects have been reproducing exponentially. Additionally, as development in the valley has increased, open spaces between neighborhoods and houses has decreased, allowing the scale crawlers to move from tree to tree with greater ease.

Scales primarily target Colorado blue spruce, a non-native plant brought to the Wood River Valley by landscapers. With the spruce came the pine needle scale. Since the insects are a non-native species, there are no natural parasitic wasps to take out the pests.

Scale activity is not limited to the spruce. Jim Rineholt, forester with the Sawtooth National Recreation Area, said it has been hitting most evergreens in the area.

"We are definitely starting to get a lot more calls on the subject," he said.

The good news, however, is that if the scales are caught in time they can be treated with a series of applications, Josey said. However, he warned that timing is everything.

"In west Ketchum if this is not addressed, it could wipe out all the spruces in the valley," he said.

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