Sources of Resistance for Two Differentially Pathogenic Strains of Xanthomonas fragariae in Fragaria Genotypes

Bacterial angular leafspot disease (BALD) of strawberry ( Fragaria sp. and F. × ananassa Duchesne cultivars) has become increasingly destructive to strawberry fruit and plant production in Canada and the United States, as well as in other countries. The disease, caused by Xanthomonas fragariae Kennedy and King, was first documented in Minnesota in 1960, and has become of worldwide concern because of the economic impact of BALD in strawberry fruit and nursery-plant production and the lack of adequate disease control strategies. We tested 81 Fragaria genotypes, including representatives of F. ×ananassa , F. chiloensis (L.) Duchesne, F. virginiana Duchesne, and F. vesca L., for resistance to two pathogenic strains of X. fragariae . Two genotypes, a native F. virginiana from Minnesota and an F. virginiana × F. ×ananassa hybrid, were found to resist infection by both bacterial strains and may be potential sources of resistance to other strains of X. fragariae .