Submitted to: Phytopathology Supplement; APSnet (Plant Pathology Online)
Publication Type: Abstract Only
Publication Acceptance Date: 3/12/2009
Publication Date: 6/1/2009
Citation: Nelson, A.H., Weiland, G.E., Hudler, G.W. 2009. Response of selected woodyspecies to inoculation with Phytophthora citricola and P. cactorum from European beech using multiple inoculation methods. Phytopathology Supplement; APSnet (Plant Pathology Online). 98:S112.
Technical Abstract: Phytophthora citricola and P. cactorum are important cosmopolitan plant pathogens with wide host ranges. Both species have recently been identified as the cause of bleeding canker of European beech (Fagus sylvatica) in the northeastern United States, but whether isolates from European beech had the ability to cause disease on other woody plant species in landscapes or forests was unclear. The objective of this research was to develop and apply methods to test pathogenicity of Phytophthora species from European beech on a variety of woody hosts. Using two isolates of P. cactorum and five isolates of P. citricola, greenhouse-grown seedlings were inoculated via one of three methods: colonized agar plugs were placed on the abaxial surface of detached leaves, zoospore suspensions were placed on wounded leaves still attached to the plant, and colonized agar plugs were inserted beneath the bark of the stem. European beech developed symptoms using all three methods. Expansion of these methods to nine additional plant species indicated varying susceptibility, with American elm, white ash, sweet birch, sugar maple, and common lilac showing leaf susceptibility, while only birch and lilac showed stem susceptibility. The ability of the pathogens to progress from the leaf into the stem - found in European beech, lilac, and birch - corresponded to general susceptibility of the stem.