Canadian Forest Service Publications
Results of a six-year plot study on Douglas-fir cone insect population fluctuations. 1964. Hedlin, A.F. Forest Science 10(1): 124-128.
Issued by: Pacific Forestry Centre
Catalog ID: 23995
Availability: PDF (download)
From 1957 to 1962 records were obtained on cone production, insect-caused damage to cones, and cone-insect populations in four plots of Pseudotsuga menziesii (Mirb.) Franco on Vancouver Island, British Columbia. Cone crops and insect populations varied extremely. In order of importance Contarinia oregonensis, C. washingtonensis, Barbara colfaxiana and Megastigmus spermotrophus were the main seed-destroyers. Apart from availability of cones, the phenomenon of diapause was probably the most important single factor affecting insect population fluctuations.