VIEW ARTICLE

Pathogenic Variability in Isolates of Cronartium fusiforme from Five Southern States. G. A. Snow, Plant Pathologist, Forest Disease Laboratory, Southern Forest Experiment Station, USDA Forest Service, Gulfport, Mississippi 39501; A. G. Kais, Plant Pathologist, Forest Disease Laboratory, Southern Forest Experiment Station, USDA Forest Service, Gulfport, Mississippi 39501. Phytopathology 60:1730-1731. Accepted for publication 1 July 1970. DOI: 10.1094/Phyto-60-1730.

Five pine progenies were inoculated with Cronartium fusiforme from five geographic sources. Two of the progenies were slash pine (Pinus elliottii var. elliottii), two were loblolly (P. taeda), and one was shortleaf (P. echinata). On the basis of previous tests, one progeny of slash pine and one of loblolly pine were regarded as resistant to the disease, while the other progenies of these species were considered susceptible. Shortleaf pine is naturally resistant to C. fusiforme. Susceptible slash and loblolly became uniformly infected by all isolates, and shortleaf seedlings were completely resistant to all isolates. Resistant slash pine showed moderate resistance to Mississippi, Texas, and North Carolina isolates, but was highly susceptible to isolates from Alabama and Florida. These results indicate that pathogenic variability occurs in C. fusiforme.