Pine bark adelgid
Upper Marlboro Maryland. I have white pines that are covered with this white powdery substance. I have about 200 of them fully matured. I looked it up and it said it was probably Pine bark Adelgid. How should I treat it.
Pine bark adelgid - Light to moderate infestations usually do not warrant control.
If the infestation is large, you can use a summer rate of horticultural oil. Follow label directions and do not spray in high temperatures. Or you can also use a dormant rate of horticultural oil after trees drop their leaves.
If you have that many trees you should think about hiring an arborist to spray.