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New Mexico State University

New Mexico State University

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Time Is Now to stop Pinyon Needle Scale

LAS CRUCES - Warm winter temperatures are causing the emergence of pinyon needle scale, a dangerous pest on pinyon pine trees throughout New Mexico, said a New Mexico State University forest entomologist.


The pinyon needle scale destroys a tree's growth from the previous year if left uncontrolled, said Bob Cain of NMSU's Cooperative Extension Service. With reports of scales laying eggs in Roswell and Socorro in the first week of February, tree owners should quickly check needles for small, black bumps.

"Pinyon needle scales may have emerged from or they may still be in those bumps, but they will be leaving them sometime this spring," Cain said. "They'll lay eggs, the eggs will hatch after about a month and the tiny crawlers will infect the new needles that grew last year."

The tiny pest will feed on the needles all summer long and those needles will die a year later. Trees already infested by last year's scale Attacks are easy to spot, he said.

"Trees that are heavily infested this year will have yellow interior needles and over time, they'll take on a skeleton appearance where they'll just have small tufts of green needles on the ends of bare branches," Cain said.

Long-term infestation, weakens a pine tree, leaving it susceptible to invasion by other pests like bark and twig beetles. Damage control begins by destroying eggs before the scales hatch.

"You'll want to look for where the egg masses are accumulating underneath branches and around the base of the tree," he said. "Use a strong stream of water from a garden hose to dislodge and wash away that cottony material with tiny yellow eggs. Then rake it up, bag it and get it away from the tree."

A follow-up spray with a registered insecticide may be necessary to thoroughly control the scales, but application timing is critical, he said.

"Once scales are settled in and covered-with their own natural wax, they're very difficult to control," Cain said. "When using any pesticide, follow all label instructions."

For more information about scale control, call your county Extension office.