Description:
Forty-seven isolates of Fusarium solani obtained
from the roots of diseased and healthy conifer
seedlings and forest nursery soil were tested for
pathogenicity on young Douglas-fir germinants
under controlled laboratory conditions. Isolate
virulence varied widely; a few were highly virulent
whereas many were classified as non-pathogenic.
Isolates from the roots of conifer seedlings were
generally more virulent than soil isolates; no
significant differences in virulence between
isolates obtained from diseased roots and healthy
roots were found. We concluded that although
some F. solani isolates commonly inhabiting
forest nurseries have the potential to elicit
disease, most are probably only slightly virulent or
non-pathogenic.