Description:
Whitebark pine, Pinus albicaulis Engelm. 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 were examined for cone
and seed insects and their impact. Ten different
insect species were found affecting various
reproductive structures of whitebark pine.
Insects having the greatest impact across most
sites were fir coneworm (Dioryctria abietivorella
(Grote)) and western conifer seed bug
(Leptoglossus occidentalis Heidemann).
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
Hopkins) 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.