THE CALIFORNIA FLATHEADED BORER (MELANOPHILA CALIFORNICA VAN DYKE) IN PONDEROSA PINE STANDS OF NORTHEASTERN CALIFORNIA

Abstract

This paper reports the findings of studies on the biology of the California flatheaded borer (Melanophila californica Van Dyke). Until comparatively recently this insect had been regarded as a relatively unimportant element of the western pine beetle problem. It has been shown that larval broods may spend a period of up to several years in an incipient stage in the living host tree. During this period the gallery of the incipient stage larva is healed over and the abnormal tissues thus developed interfere with normal conduction in the wood. Undetermined factors associated with the dying of the host tree initiate a fast-growing larval stage in which feeding is voracious and growth rapid.No attempt is made to set forth the role of the species in the complex known as the western pine beetle problem. It is, however, suggested that this insect, at least in northeastern California, may play a more important role in insect caused losses in commercial stands of ponderosa and Jeffrey pine than had previously been believed. The contributions to the knowledge of the biology of the species may assist in an eventual better understanding of insect–host relationships in this particular problem.