Airdog - I may be able to help, but I have several questions. What region are you from? Have you inspected the branches closely to rule out insects (sawfly, needleminers, budworm, aphids etc.). Look really close.
What type of soil are they growing in (moisture and nutrient availibility)?
Have the last two growing seasons been significantly dryer than usual?
Could these trees be too dry?
Any other description would be helpful.
Regarding blights, look under the dead needles to see if there is any evidence of fruiting bodies of the agent - they will look like little brown/black nodules. I would suspect Sirococcus shoot blight. The agent often prefers the younger red pine trees, but will alternately use spruce as a host. This blight should only attack this year's growth, so use that as a clue. It should weaken the tree, but not kill it. Watering is your best defense - makes the tree stronger, hence my question about soil and drought above.
A more serious blight is Diplodia tip blight. It can kill your trees. If you look for fruiting bodies and are able to identify both second year's growth as being attached and cankers with pitch in them (and fruiting bodies), you may have Diplodia tip blight. Fungicides may be effective if applied at the right time by a qualified person, but again, the agent is more damaging to weak trees, so provide supplemental water if needed.
If it's insects, respond with details, I'll try to help.
