Differential Susceptibility of Ponderosa Pine to the Gouty Pitch Midge ('Cecidomyia piniinopis')

摘要

In 1985, 14-year-old ponderosa pine in a provenance test in northern Idaho were severely damaged by the gouty pitch midge. Dead or dying tips varied from 0 to 85% for individual trees, and 0 to 17% for provenances. The most resistant provenances came from seed collected in northern-most Idaho and northwestern Montana where the midge is more abundant than in the southern portions of the study area, comprising central Washington, the northern slopes of the Salmon River, and the Bitterroot River of Montana. Resistance to the midge apparently is an inherited trait influenced by degree of exposure of parent trees.