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Resistance

Increase in Virulence of Cronartium fusiforme on Resistant Slash Pine. G. A. Snow, Principal Plant Pathologist, Southern Forest Experiment Station, U. S. Department of Agriculture, Forest Service, Gulfport, Mississippi 39501; R. J. Dinus(2), and C. H. Walkinshaw(3). (2)(3)Principal Plant Geneticist, and Principal Plant Pathologist, Southern Forest Experiment Station, U. S. Department of Agriculture, Forest Service, Gulfport, Mississippi 39501. Phytopathology 66:511-513. Accepted for publication 10 November 1975. DOI: 10.1094/Phyto-66-511.

Cronartium fusiforme from field-infected members of a highly resistant slash pine family infected more seedlings of the same parent than did samples of C. fusiforme inocula collected from the general rust population. Greater virulence of inocula from resistant trees is evidence of pathogenic specialization in C. fusiforme.