Bristle Cone pine scale

Asked April 3, 2019, 11:59 AM EDT

I noticed what looks like scale on my Bristle Cone pine but have read they excrete a whits substance naturally also. How do I tell the difference?

Eagle County Colorado scale insects bristlecone bristlecone pine resin bristlecone resin

1 Response

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Although the resin on bristlecone pine trees can resemble scales, there are a few distinctions:
Scales are usually uniform in shape/size, and appear to be flatter and flush with the surface of the needles. Scales also have a brown spot at the narrow tip (the head) which is also easy to differentiate. If you peel back scales you can sometimes see legs on the underside of the scale, and discoloration on the needles as a result of them. There are also often some sticky residue (honeydew) on the surface of the plant as a result of these scales.
You can learn more about scales on conifers here:
https://extension.colostate.edu/topic-areas/insects/scale-insects-affecting-conifers-5-514/

The resin that naturally occurs on the bristlecone pines are irregular in shape/size and don't have any of the aforementioned distinguishing characters.

Your tree appears to be healthy, and showing spots of natural dried resin!

Thanks,