01430naa a2200169 a 450000100080000000500110000800800410001910000180006024501380007826000090021652008750022565000310110065000260113165000120115765000100116977300810117912797412025-02-28       1986    bl uuuu     u00u1 u    #d1 aALFARO, R. I.  aMortality and top-kill in douglas-fir following defoliation by the western spruce budworm in British Columbia.h[electronic resource]  c1986  aSurveys of mortal ity and top-kill caused by th e western spruce budworm, Choristoneura occidentaliss Freeman, in 65 stands of Douglas-fir. Pseudotsuga menziesii (Mirb.) Franco arc reported. Top-kill was detected in 85% of the s ta nds and 25o/c of the trees surveyed. Mortality amounted to 8% and less than 1% of the trees examined in the Vancouver and Kamloops Forest Regions. respectively. Both frequency of top-kill and mortality were related to the number of years defoliation in the stand and were higher on suppressed trees than on dominant or codominant trees. Younger stands sustained a higher incidence of top-kill than older stands. Tree mortality was higher on steep s lopes than on ilatterrain. These results suggested that lop-kill or mortality were the re.sults of physiological stress on the tree,. in addition to the dehilitaling elTects of defolialion.  aChoristoneura occidentalis  aPseudotsuga menziesii  aLagarta  aPraga  tJournal of Entomological Society of British Columbiagv. 83, p. 19-26, 1986.