The impacts and timing of insect infestation were determined in developing Engelmann spruce cones throughout the summer of a year of low cone production in northern Utah. The major insects found were the western spruce budworm, Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae); fir coneworm, Dioryctria abietivorella Grote (Lepidoptera: Pyralidae); and the spruce seed moth, Laseyresia youngana Kearfott (Lepidoptera: Olethreutidae). Insects reduced the survival of cones to 11.48 cones out of 100. The high percentage of seeds and cones lost to insect predation supported previous studies of a similar nature.
Cameron, D. E. and Jenkins, M. J.
"Engelmann spruce cone losses caused by insects in northern Utah in a year of low cone production,"
Great Basin Naturalist: Vol. 48
, Article 8.
Available at: http://scholarsarchive.byu.edu/gbn/vol48/iss4/8