Promptly cut out and destroy dying branches. Trim back to trunk or nearest healthy lateral branch. Do not prune in wet weather. Disinfect pruning tools between cuts. Older needles turn purplish brown.
Younger needles remain green.
Branches may die after three or four years of defoliation. Prune surrounding vegetation to increase air circulation. Repeat as label directs. Severely affected branches may die. See MU publications G 7274 and G 7273 University Outreach and Extension does not endorse commercial products.