RESISTANCE OF WHITE SPRUCE TO WHITE-PINE WEEVIL - DEVELOPMENT OF A RESISTANCE INDEX

An index of resistance in white spruce, Picea glauca (Moench) Voss, to attack by the white pine weevil (Pissodes strobi Peck) was developed based on tree variables which measured attack intensity, severity and the tolerance of the tree to attack, The index, derived using principa l component analysis, was used to screen 139 white spruce families fro m the interior of British Columbia in a replicated family trial, for r esistance to weevil attack, The resistant ranking of the families was significantly related to the habitat characteristics of the parent tre es as measured by,elevation, longitude, latitude and by the ecological variables of biogeoclimatic zone, subzone and variant. Geographic sou rces of white spruce genotypes resistant to weevil attack were identif ied. These were mainly in the moist-warm habitats of the SubBoreal Spr uce biogeoclimatic zone.