OBSERVATIONS ON ARMILLARIA MELLEA IN IMMATURE DOUGLAS FIR

Abstract

ARMILLARIA MELLEA (Vahl) Quél., the cause of shoestring root rot, was observed attacking all vigor classes in Douglas fir plantations. In vigorous stock the formation of latent cankers on the roots precluded the active spread of the disease. From these cankers the fungus frequently moved into the woody core causing yellow spongy butt and root rot, which is not fatal to the host. Planting trees on poor sites or with poor technique resulted in severe outbreaks of the disease.