Variation in attack by Sitka spruce weevil, Pissodes strohi (Peck), within a resistant provenance of Sitka spruce

Abstract

Variation in tree height and numbers of attacks by the Sitka spruce weevil (= white pine weevil), Pissodes strohi (Peck), were studied among families of a resistant provenance of Picea sitchensis (Bong.) Carr. at two Vancouver Island sites. At Sayward, after 14 years, the number of trees attacked varied by family from 0 to 80%. A significant association was found between the percentage of trees attacked in a family and the mean height of the family. Tall families were generally attacked more. At Fair Harbour (a clonal test), only 12% of the trees from the resistant provenance have been attacked after seven years, with all but one of the attacks concentrated on one of the two families tested. A multigenic or multicomponent basis for resistance is proposed and discussed

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