ON THE SPREAD OF FOMES ANNOSUS (FR.) CKE.

Basidiospores of Fomes annosus (Fr.) Cke. were found to be wind-dispersed and to be deposited on soil, seedlings, tools, and other objects in the fields of the Provincial Forest Tree Nursery at St. Williams, Ontario.Spores deposited on the root systems and needles of red pine (Pinus resinosa Ait.) nursery seedlings remained viable and ungerminated for 8 weeks, while the seedlings were kept in shipping bales and storage. Direct infection of seedlings was not observed under these conditions. However, roots of recently cut trees were successfully infected with F. annosus, when basidiospores carried on seedlings were transferred to the surfaces of roots wounded in a planting process.The danger of the spread of Fomes root rot from southern Ontario into northern Ontario is discussed. A delay of 2 to 3 years in replanting cut-over areas is suggested as a possible preventive measure against the introduction of F. annosus with planting stock.