Changes in water status in seedlings of six species in the Fagaceae after inoculation with Raffaelea quercivora Kubono et Shin-Ito

To clarify the differences in susceptibility of six species in the Fagaceae (Quercus crispula, Quercus serrata, Quercus acutissima, Quercus phillyraeoides, Quercus glauca, and Castanopsis cuspidata var. sieboldii) to Raffaelea quercivora, we inoculated this fungus on seven potted 5-year-old seedlings of each species, observed symptom development, and measured xylem pressure potential (XPP) after inoculation. The first death was observed on the 11th day in Q. crispula and on the 56th day in Q. serrata. The number of dead seedlings of Q. crispula and Q. serrata were five and one, respectively, whereas no mortality was observed in the other four species. The XPP of inoculated seedlings in both Q. crispula and Q. serrata decreased after inoculation. In contrast, the XPP of inoculated seedlings of the other four species remained almost the same as in the control seedlings. These results indicate that R. quercivora is pathogenic to Q. crispula and Q. serrata and that the susceptibility of the six Fagaceae species in our study differed among species.