Objectives:

To observe the development of Armillaria root disease caused by A. ostoyae in Douglas-fir plantations at Nakusp and Sugar Lake (Vernon District).

Experimental Design:

Layout:

At each site, a 100 by 200 m block was laid out. The 2 ha area was divided into eight 50 by 50 m blocks marked by metal posts to facilitate mapping of disease centers. Blocks were carefully searched for symptomatic trees and their locations were marked and tagged. Posts were placed near the centre of groups of dead and symptomatic trees, and post coordinates were measured. Disease centre posts were used to map dead and symptomatic trees and adjacent stumps of the previous stand. Year of death is known for all trees killed by A. ostoyae. Plots are assessed biennially and maps are updated after each examination. Using the maps, the temporal and spatial development of the disease has been followed.

History:

• 1984 - Sugar Lake plot established in a 1967 plantation.
• 1986 - Nakusp plot established in a 1972 plantation.
• Plots assessed for mortality and new infections in even numbered years
• 2002 - Report planned

Status: Active

Reports and Publications:

Morrison, Duncan and Kevin Pellow. 1994. Development of Armillaria root disease in a 25-year-old Douglas-fir plantation. pp 560-571 In: Proceedings of the Eighth International Conference on Root and Butt rots. August 9-16, 1993, Wik, Sweden and Haikko, Finland.

Peet, F.G., D.J. Morrison and K.W. Pellow. 1996. Rate of spread of Armillaria ostoyae in two Douglas-fir plantations in the southern interior of British Columbia. Can. J. For. Res. 26:148-151.

Comments:

Mortality is still occuring, with new trees being detected. However, only a few disease centres are still active.