I should have also included that i had a Crepe Myrtle that had small white fuzzy scale that I treated with a Bioadvanced systematic treatment (Imidacloprid and clothainidin - see pic) spread in pellet form under mulch around the tree that worked great for that.

Any reason I shouldn’t give that a try on this too - it says it treats soft scale infestations? If I chose to try this when is best timing - now while they are in scale state or wait till the little buggers hatch and start feeding?

Hi Jonathan,

Imidacloprid was banned for residential consumers in Maryland under the Pollinator Protection Act of 2016, which took effect on January 1, 2018. The law bans the retail sale and consumer use of neonicotinoid pesticides, including imidacloprid, for outdoor residential applications on lawns, gardens, and ornamental plants. Its use is now restricted to Certified pesticide applicators, farmers, and veterinarians, so no, we cannot recommend using it on your ornamentals.

From your picture and description, those do appear to be European elm scale. There is one generation a year with juveniles overwintering on the bark. The reddish brown you see upon scraping them off is their guts! Being a soft scale, they also exude honey dew, which black sooty mold grows on. That's what you noticed last fall. You mentioned seeing lots of lady beetles - this scale is usually controlled by beneficial insects. 

Since these trees are 25' tall, you may want to consider hiring a certified arborist to assess the population and treat them at the appropriate time. They would have access to some of the better systemic materials that have replaced imidacloprid.

Marie