Tiny white lumps on crepe myrtle-good or bad?

Question: Hi, there. I live in Olney, Md and came back after a vacation to see these white spots all over my crape Myrtle! Tree stands alone and is south-facing with good drainage. Can you tell me what they are and what, if anything, I need to do about them? They are not moving.

responder: Answered by theHome and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied October 08, 2024, 1:00 PM EDT
response: This looks like a relatively new pest in Maryland called Crapemyrtle Bark Scale. Here is our page about them:  https://extension.umd.edu/resource/crapemyrtle-bark-scale-home-gardens/ The good news is that you are seeing it early and can consider scrubbing off some of them (that you can reach) with a brush and soapy water. Since they are new here, we are still learning about their life cycle in our area but we were happily surprised this year to find them being controlled by beneficial insects, especially the larval stage of lady beetles. See the link above- they look a good deal like the scale but are larger, more fluffy and have legs and can move quickly.   Christine

responder: The Question Asker Replied October 08, 2024, 8:35 PM EDT
response: Thank you. I gave the trunk (and branches I could reach) a good scrub with soapy (Dawn) water. Then I rinsed with the jet setting to clean the bark, and most came off. Fingers crossed.  Should I spray again with anything or was rinsing okay?Thanks,Tami

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied October 09, 2024, 9:33 AM EDT
response: Treatment options for scale insects can be found on the page Christine linked to, and the other page it connects with, our Introduction to Scale Insects page (the bottom section discusses management approaches). Horticultural oil is one of the least-toxic insecticides that can be used, though it doesn't always work fully to eradicate a population, as the spray has to directly contact each insect in order to kill it (dried residues have no effect). The linked page has more information about using hort. oil, including a "dormant oil" rate that is more effective during winter but which cannot be used when the weather is too warm or the plant still has foliage.  There are some beneficial insect predators of this scale that will consume them, so avoid spraying them with insecticide (of any type) or scrubbing them off. The "natural predators" section of the Crapemyrtle Bark Scale web page provides examples of what to look for, especially since one of them looks very similar to the scale itself. Scrubbing/rinsing dense numbers of scale off the bark and then letting beneficial insects take care of the remaining population might be enough, and fortunately low numbers of this scale won't cause the Crapemyrtle any significant damage, so complete eradication is not necessary.  Miri

responder: The Question Asker Replied October 09, 2024, 10:32 AM EDT
response: Thank you so much for that very helpful information.  On Wed, Oct 9, 2024, 9:33 AM Ask Extension <<personal data hidden>> wrote:

responder: Answered by the Home and Garden Information Center (HGIC), University of Maryland Extension. For timely gardening information and tips, subscribe to our Maryland Grows blog and quarterly newsletter. Follow us on Facebook, Instagram, and YouTube. Replied October 09, 2024, 10:58 AM EDT
response: You're welcome!