"C M Brasier (Forest Research Station, Alice Holt Lodge, Farnham, England, pers. comm.), who examined the initial seven isolates of O. novo-ulmi obtained obtained from diseased trees in Auckland. He found that all isolates were of the NAN Europeans vegetative compatibility supergroup, which is often the dominant vegetative compatibility group in western Europe at current epidemic fronts (Brasier 1988). He also considered that as all isolates were morphologically very similar, the outbreak may well comprise a single close of the NAN aggressive subgroup. The involvement of this group [points to western Europe as the most likely source of the New Zealand fungus."