Damage by the Sitka spruce weevil (Pissodes strobi) and growth patterns for 10 spruce species and hybrids over 26 years in the Pacific Northwest.

Abstract

Ten species and hybrids of spruce (Picea spp.) were planted and observed annually for 26 years at three coastal locations in Oregon and Washington to evaluate growth rates and susceptibility to the Sitka spruce weevil (= white pine weevil), Pissodes strobi The 10 spruce were: Sitka spruce, Norway spruce, Lutz spruce, black spruce, white spruce, Engelmann spruce, Yeddo spruce, Sakhalin spruce, an Engelmann x white spruce cross, and a Sitka x white x white backcross. Results showed Sitka and Norway spruce grew well but were badly damaged by severe weevil attack. Infestation levels peaked at about 30 percent between 9 and 15 years and dropped to about 8 percent at the end of the study. Lutz spruce--a natural Sitka/white spruce hybrid--was rarely weeviled and some trees grew well while others grew poorly. The conclusion was that Lutz spruce demonstrates resistance to weevil attack, that the resistance is genetically based, and that this resistance could be exploited in a tree-improvement program. The other species and hybrids had very little weevil damage, but survival and growth were poor.

Citation

Mitchell, Russel G.; Wright, Kenneth H.; Johnson, Norman E. 1990. Damage by the Sitka spruce weevil (Pissodes strobi) and growth patterns for 10 spruce species and hybrids over 26 years in the Pacific Northwest. Res. Pap. PNW-RP-434. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 12 p