A field caging technique was used to test the susceptibility of 25 white spruce, Picea glauca (Moench) Voss, seed sources to attack by Pikonema alaskensis (Rohwer). No sig- nificant differences were found in the number of eggs laid, number of dessicated eggs, or number of egg slits. Percent oviposition differed significantly within a tree, the south side having more eggs. Bud size differed significantly within trees and between trees but not between seed sources. The number of sawfly eggs laid on a bud could not be related to bud size. There was no significant difference in susceptibility of the seed sources studied to Pikonema alaskensis.
Connor, Michael D.; Houseweart, Mark W.; and Kulman, Herbert M.
"Susceptibility of White Spruce Seed Sources to Yellowheaded Spruce Sawfly, Pikonema Alaskensis,(Hymenoptera: Tenthredinidae),"
The Great Lakes Entomologist, vol 15
Available at: https://scholar.valpo.edu/tgle/vol15/iss3/12