Cone and seed insects and their impact on whitebark pine.
Whitebark pine, Pinus albicaulis, is an important but declining high-elevation tree species in western forests. Regeneration of this species has been difficult and the impact of cone and seed insects unknown. Seven sites selected from the geographical range of whitebark pine in Idaho, Montana, Washington, Oregon, and California, USA [date not given] were examined for cone and seed insects and their impact. Ten different insect species (Polyphylla crinita, Frankliniella occidentalis, Xyela spp., Dichelonyx fulgida, Dioryctria spp., Dioryctria abietivorella, Conophthorus ponderosae, Leptoglossus occidentalis, Cydia spp., and Pineus spp.) were found affecting various reproductive structures of whitebark pine. Insects having the greatest impact across most sites were fir coneworm (Dioryctria abietivorella) and western conifer seed bug (L. occidentalis). Coneworms infested up to 68% of cones collected, destroying up to 13% of the seed extracted. Seed bugs damaged up to 27% of the seeds. Pheromone traps for the ponderosa pine cone beetle (Conophthorus ponderosae) and coneworms were tested. Ponderosa pine cone beetles were trapped at three of seven sites. Coneworms were trapped at two sites where pheromone traps were deployed. Further studies incorporating different cone crop levels of whitebark pine and other associated tree species are needed to fully determine the effect of cone and seed insects on whitebark pine seed and reproduction.