STUDIES ON WHITE PINE BLISTER RUST IN NOVA SCOTIA

Studies were undertaken in Nova Scotia to determine (i) the effect of different cutting practices on the establishment of a RIBES population and of white pine regeneration, (ii) whether blister rust is a major factor in retarding the establishment of white pine regeneration, and (iii) the feasibility and cost of RIBES eradication as a direct control measure against blister rust. No relationship was found to exist between RIBES establishment and the degree of cutting. Uncut softwood stands, where white pine is the predominant species, show evidence of producing a future pine crop. Forest types supporting white pine appear to offer the best opportunities for pine reproduction where a clear-cutting operation has given the stand maximum opening. Results of the present study to date do not show that blister rust is a major factor in retarding the establishment of white pine regeneration. To eradicate RIBES from the study area by a complete systematic search required 1 man-hour per acre. Because of the small number of RIBES plants found and of the tendency for them to occur consistently in moist, low-lying habitats, a complete systematic search for these plants appears to be unnecessary. It is suggested that one man, trained to recognize RIBES and their probable location, could cover large forest tracts with a minimum of time expended in searching localities unlikely to support these plants.