Pine – Galls, Yellow Powder
Q: This morning we saw a pine tree with five of these knots on it. When I touched it with a twig, a powdery pollen-like substance puffed from it.
A: The galls are caused by Eastern gall rust. This fungus is common on pines. It weakens the infected trunk or limb.
There’s no chemical control. Best to prune the galls out whenever seen.