Observations on Mortality Factors of the Fir Engraver Beetle, Scolytus ventrails (Coleoptera: Scolytidae)1

Abstract

Mortality of eggs and larvae of Scolytus ventralis LeConte in 3 small white fir trees exceeded 85%. Biotic mortality factors include predaceous beetles, parasitic insects, predaceous and parasitic mites, and fungi. Other causes of mortality are intraspecific competition for food and space, and interspecific competition with other bark beetles.