Two isolates of the edible ectomycorrhizal fungi (ECM), Lactarius deliciosus and Rhizopogon roseolus, were tested against
Fusarium oxysporum and F. verticillioides, causal agents of damping-off on seeds and seedlings of Scots pine (Pinus
sylvestris) and stone pine (Pinus pinea). The effects of ECM on Fusarium spp. in the rhizosphere of Scots and stone pines
were evaluated by: (1) co-inoculating ECM and Fusarium when seeding (seed test) and (2) co-inoculating eight-week-old
seedlings (seedling test). The seed tests showed significant reduction of Scots pine seed germination when treated with F.
verticillioides, but this effect was absent when co-inoculated with R. roseolus. Higher germination rates were observed in
stone pine when F. oxysporum was co-inoculated with L. deliciosus than the pathogen inoculation alone. In the seedling
test, Scots and stone pines were not apparently affected by Fusariumspp. No obvious changes in plant growth-related variables
were observed in either assay. Root colonization of Scots and stone pine seedlings by R. roseolus was 15.5% and 12%
for the seed assay, as well as 21.6% and 11% for the seedling assay. Lactarius deliciosus mycorrhizal roots were found only
in Scots pine seedlings (10%). Rhizopogon roseolus and L. deliciosus are two promising fungi for pine seedling protection
against Fusarium damping-off at nurseries.