Ray, I'm sorry I haven't gotten back to you, but between my animal rescue activities and packing to go away, I just haven't been able to give this the time it needs.** :?
I think the white residue could be what is left of some pest, possibly mealy bugs or scale insects.* The pirate bug probably ate them and you see the remains.
I'm glad you found a spray that will work for you, but I probably would have suggested an insecticidal soap or an organic horticultural oil.
Thanrose, thank you so much for helping out here.* Your suggestions* and knowledge are always welcome!
I will return about the 29th of May.
When weeding, the best way to make sure you are removing a weed and not a valuable plant is to pull on it. If it comes out of the ground easily, it is a valuable plant.