02251nas a2200169 4500008004100000022001400041245016600055210006900221260001600290300001400306490000700320520162300327100002301950700001801973700001901991856007102010 2021 eng d a0032-086200aPathogenicity and infectivity of Phytophthora ramorum vary depending on host species, infected plant part, inoculum potential, pathogen genotype, and temperature0 aPathogenicity and infectivity of Phytophthora ramorum vary depen cOct-19-2020 a287 - 3040 v703 a

A total of 25 ornamental plant species representing 10 families were inoculated using three genotypes, each representing one of the genetic lineages NA1, NA2, and EU1 of the pathogen Phytophthora ramorum. Leaves were inoculated using suspensions with two zoospore concentrations and exposure at three temperatures, while stems were inoculated using agar plugs colonized by mycelia. Susceptibility was determined by measuring either the success of pathogen reisolation or lesion length caused by the pathogen. Infectivity was determined by counting sporangia in washes of inoculated leaves or stems. Results from all three pathogen genotypes combined were used to rank each of the 25 plant species for susceptibility and infectivity, while pooled results per genotype from all 25 hosts combined were employed for a preliminary comparison of pathogenicity and infectivity among genotypes. Statistical analyses showed that leaf results were affected by the concentration of zoospores, temperature, plant host, pathogen genotype, and by the interaction between host and pathogen genotype. Stem results were mostly affected by host and by the interaction between host and pathogen genotype. Hosts ranked differently when looking at the various parameters, and differences in rankings were also significant when comparing stem and leaf results. Differences were identified among the 25 hosts and the three pathogen genotypes for all parameters: results can be used for decisionā€making regarding regulations or selection of plants to be grown where infestations by P. ramorum are an issue.

1 aGarbelotto, Matteo1 aSchmidt, Doug1 aPopenuck, Tina uhttps://bsppjournals.onlinelibrary.wiley.com/doi/10.1111/ppa.13297