. Biology of rust resistance in forest trees : proceedings of a NATO-IUFRO advanced study institute, August 17-24, 1969. Trees; Pine; Trees; Rust diseases. ENVIRONMENT AND WHITE PINE BLISTER RUST INFECTION 481 The variation is tremendous between the 29 stands prior to eradica- tion (18 of these stands are shown in Fig. 1). The pre-eradication incidence of rust ranged from no cankers per 100 trees to the greatest infection in a given year of 118 cankers per 100 trees. This variation can be ascribed to environmental differences since all stands had abun- dant ribes present. The number of repeate
. Biology of rust resistance in forest trees : proceedings of a NATO-IUFRO advanced study institute, August 17-24, 1969. Trees; Pine; Trees; Rust diseases. ENVIRONMENT AND WHITE PINE BLISTER RUST INFECTION 481 The variation is tremendous between the 29 stands prior to eradica- tion (18 of these stands are shown in Fig. 1). The pre-eradication incidence of rust ranged from no cankers per 100 trees to the greatest infection in a given year of 118 cankers per 100 trees. This variation can be ascribed to environmental differences since all stands had abun- dant ribes present. The number of repeatedly observed sample trees was adequate. The median number was about 250 trees per stand, with the range in individual stands from 75 to 1,500 trees. After eradication, nearly all of the variation was removed since all plots had less than 20 cankers per 100 trees and all but two had less than 5 cankers per 100 trees. Incidentally, the total results of 5,174 cankers in the four years prior to eradication (67 per 100 trees) compared to 103 cankers in the four years after eradication ( per 100 trees) was significant at the 1 in 1000 level (Van Arsdel, 1968). Almost any series of infection plots will show variation in the infection level. The question is, can we systematize this variation so we can predict where the heavy, light., and lack of infection will occur? The answer is: we Figure 1. Differences in the amount of blister rust infection occurring on 18 of 29 study Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original North Atlantic Treaty Organization; International Union of Forestry Research Organizations; United States. Forest Service; University of Idaho. Washington, D. C. : Forest Service
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Keywords: ., bookauthoruni, bookcentury1900, booksubjectpine, booksubjecttrees
