Desert willow bark(?) bugs

Question

I live in southern NM & have more that 16 desert willows in my yard. They have been here for at least 10 years. Recently, I noticed what looked like mud on their bark. When I brushed it off, I saw thousands of very tiny, dark bugs. Should I be worried? If so, what should I use on them?

Answer 1

The black on the bark is likely Sooty Mold, which is generally caused by a Scale or Aphid pest.
I would treat them with Neem Oil.

https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
https://www.gardeningknowhow.com/plant-problems/disease/how-to-get-rid-of-sooty-mold.htm