Comparison of the susceptibility of Quercus petraea, Q-robur and Q-rubra to Collybia fusipes

Collybia fusipes is the cause of a root rot of Quercus petraea (sessile oak ), Q. robur (pedunculate oak) and Q. rubra (red oak). This parasite is ofte n reported to cause problems in stands of red oaks and field evidence sugge sts that this North American oak species is more susceptible than the two E uropean oak species. Young saplings of the three oak species and of chestnu t, Castanea sativa, in the glasshouse, and also mature sessile and red oaks growing in the same stand were inoculated with C. fusipes to compare their susceptibility. Red oak, both as young seedlings and mature trees, was mor e susceptible to C. fusipes than sessile oak. Chestnut seedlings were as su sceptible as sessile oak. Susceptibility of pedunculate oak seedlings was i ntermediate between red oak and sessile oak. In one experiment this species was significantly less susceptible than red oak, and in the other it was a s susceptible.