Canadian Forest Service Publications
Growth reduction in lodgepole pine defoliated by the needle miner Evagora (Recurvaria) starki Freeman. 1961. Cook, J.A. Forestry Chronicle 37(3): 237-241.
Issued by: Northern Forestry Centre
Catalog ID: 30666
An outbreak of the needle miner, Evagora starki (Free.) occurred in the Canadian Rocky Mountain National Parks between 1938 and 1952. Defoliation reached 70 per cent in one area at the peak of the outbreak. Growth reduction was detected only when defoliation exceeded 40 per cent. Volume loss varied from 2 to 10 cu. ft. per acre per year over periods of 3 to 14 years depending on the stand character. There was good agreement between the length of time defoliation exceeded 40 per cent and the per cent loss of increment. The average increment loss for all infested stands was 43.2 per cent, ranging from 21.2 to 74.7 per cent. Infestation records were not accurate enough to relate the intensity of defoliation with growth reduction. High levels of infestation did not persist long enough to cause any significant tree mortality.