Second call concerns white pines that are 40-50 years old and are dying from the top down. Owner thinks trees next to affected trees are also becoming affected. He is wondering about the possibility of nematodes or a soil fungus.
Sandy soils in our area, could this be injury due to water issues?
On smaller trees- look for root collar weevil on soil line - Infested trees look similar to what is going on
Suspect something more complicated in large trees
I'd check for stresses that might lead to reduced water uptake (e.g., drought stress, girdling root, salt exposure). From a pathology standpoint, I'd look for root rots. Also Armillaria root disease is a possibility. The causal pathogen in this latter disease forms mushrooms in the root zone of the tree. To verify any possible diseases, I'd need to see a sample in the clinic.