Your white pines are infested with White pine weevil - a beetle that lays
eggs on the terminal branch. The eggs hatch and the larvae bore into the
wood of the terminal branch in spring. Symptoms you see express in the
summer when the damage is done.
Depending on state law the way to go about this is to treat with a repellent
insecticide in early spring. Things like Talstar, Lindane, permethrin, etc.
have been used for this in the past.
best to prune out the dead terminal, and trim the remaining live laterals to
establish a new leader.
Call a consulting arborist for further details or email off list.
Mike LaMana, MS
Heartwood Consulting Services, LLC
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