Attainment of the Overwintering Instar and the Casebearing Habit by Larch Casebearer Larvae at Different Elevations in the Blue Mountains

摘要

The percentage of casebearing larvae on plots between 3,280- and 5,545-ft (1,000- and 1,690-m) elevation increased between September 11 and October 25 from 2.6 percent to 93 percent. Larvae at all elevations had reached the third (overwintering) instar by October 10. This information is useful in timing parasite releases or insecticide applications. Larvae at 4,000 ft (1,219 m) advanced more rapidly than larvae at higher or lower elevations.