Several insects mine buds and shoots, primarily of young trees. Although seldom killed, trees are retarded in growth when infestations are severe. Pine tip moths (Rhyacionia spp.) and the gouty pitch midge (Cecidomyia piniinopis) kill the buds and shoots they mine. A more insidious pest, until recently overlooked and overrated, is the western pineshoot borer (Eucosma sonomana) (21). Larvae of this species bore within the pith of the terminal shoot, stunting but seldom killing them. Shoots that are potentially more robust are more likely to be infested than are weaker shoots. Accordingly, direct comparisons of infested vs. uninfested shoot lengths will underestimate actual growth loss. Each terminal shoot infested by a larva that developed to maturity was reduced in length that year by more than 25 percent in one study (59).  The pine reproduction weevil (Cylindrocopturus eatoni), a native of California and, presumably, Oregon, can be a threat to slow-growing plantations. Its impact has declined, however, with the improvement in planting stock and control of competing vegetation.  Defoliating insects, such as the pine butterfly (Neophasia menapia) and the pandora moth (Coloradia pandora), periodically cause damage over extensive areas. The pine needle sheathminer (Zelleria haimbachi) can be locally severe in young stands.