Branch and twig dieback. Preventive trunk sprays when adults are active can reduce new attacks. Thorough coverage is important, especially around active infestation sites. Two to three treatments each season, repeated over at least two years, may be needed. Pyrethroids, Cygon and Dursban are among the most effective sprays.
Needles change from green, to yellow to reddish brown.
Promote tree vigor with proper watering, spacing and nutrients. Newly planted or stressed trees are highly susceptible. Reduce stress to reduce susceptibility. To prevent subsequent generations, thoroughly wet bark and branches with preventive insecticides prior to egg laying in late March to early April and late July to early August. Sevin, Dursban or Astro are recommended as preventive insecticide sprays.