Growth of white firs defoliated by Modoc budworm in north eastern California

摘要

Open-grown, pole-sized white firs defoliated by Modoc budworm (Choristoneura viridis) in northeastern California in the years 1959-62 and 1973-75 suffered only minor growth reductions and topkilling compared with the effects that more protracted budworm outbreaks have had elsewhere on their conifer hosts. Growth index analysis indicated that the first averaged a cumulative height growth deficit of 14.5 percent, or 34 cm (1.1 ft), over both outbreaks.