Have the crawlers in pinon needle scales already crawled this year?

Asked March 18, 2013, 2:56 PM EDT

I have noticed the dying of the needles on several pinons in my yard and in those of my mother in law. I have identified the culprits to be pinon needle scales. The black "beans" are on the needles are these last years? or have the crawlers already hatched for this year. So i
I need to know if I can still treat the pinons this year and hopefully stop the damage. I have removed some branches and hard water sprayed those left. There are still black "beans" present, but no webbing or egg masses.

Bernalillo County New Mexico

1 Response

This sounds like pinyon needle scales. The 'black beans' are from the overwintering stages in the most recent generation. While the literature suggests 'spring' as the time adults emerge, crawl down the tree and reproduce, it appears micro-climate has a major impact, too---with some adults emerging much sooner than others. Some even emerge in the fall and likely die for their mistake.

The strong streams of water approach is a good starting point for addressing the problem. This blasts of millions of the overwintering stages, emerging adults, eggs and young crawlers---rake up the debris under the tree after about 20 minutes of dripping; bag it and throw it away. Some people just keep giving 'power showers' to the tree as long as they detect crawlers (use a hand tool to knock some loose from the branches onto a paper tablet---watch for movement). Others opt for a light horticultural oil spray to smother the crawlers and survivors. Still others may use the systemic imidacloprid (granular formulation for soil application).

Tree inspection should be done annually in late winter. If the beans are present, check for crawlers using the hand tool to whack branches over a paper tablet. That's good confirmation of pest activity. Then make your management decision and carry it out. Check for crawlers again after a week or two to determine efficacy.