Question
I have a Jack Pine in my yard. It has a black powder that is covering the tree and
killing it quickly. It's not the first to fall from this fungus. Nobody can tell me
what it is... can you? Maybe a treatment?

Answer
Sounds like sooty mold.

If it is on the foliage and the area is sticky to the touch it is a fungi called sooty mold. Sooty mold grows on a substance called honeydew. Honeydew is secreted by an insect called an aphid or a scale. These insects suck the plant juices from the plant and secrete a sticky high sugar content liquid. The sooty mold is growing on this sugar. It is more than likely scales--which look like small turtles attached to the twigs. IF it is aphids these insect will be moving around the foliage and twigs where scales are attached and not moving.

Both can be controlled with the use of an insecticide called Bayer Advanced Insect control for trees and shrubs. This is applied to the soil around the tree and the roots will transport the systemic insecticide to the plant foliage an twigs killing the insect when they suck the juices. Once you control the sucking insects the sooty mold will go away or washed off with rain.