Authors
A. F.
Egan
,
Assistant Professor, Division of Forestry, West Virginia University, Morgantown 26506-6125
; and
W.
Merrill
,
Professor of Plant Pathology, The Pennsylvania State University, 211 Buckhout Lab, University Park 16802
ABSTRACT
The effects of Endocronartium harknessii on provenances of Pinus ponderosa planted in 1969 on a coal strip-mine spoil bank in central Pennsylvania were reassessed. In 1982 infection levels among seed sources ranged from 4.9 to 52.5%. In 1991 infection levels ranged from 29 to 95%, and mortality due to rust infection ranged from 9 to 58% among these seed sources. Levels of infection, mortality due to rust infection, and mortality unrelated to rust infection differed significantly among seed sources (P < 0.001, < 0.001, and = 0.023, respectively). Among geographic ecotypes, there were no significant differences among percentages of trees infected (P = 0.094), but there were significant differences among trees surviving outplanting (P = 0.007), mortality due to rust (P = 0.004), and mortality unrelated to rust (P < 0.001). Only one provenance incurred less than 40% infection, indicating that virtually none of these types of provenances are suitable for reforestation in areas of eastern North America where E. harknessii occurs.
