The connection between Dematophora necatrix and Rosellinia necatrix

Abstract does not appear. First page follows.

Since the first thorough study of Dematophora necatrix (Hart.) by Hartig.⁽¹⁾6 who suggested its relationship to the genus Rosellinia, there has been a reasonable doubt as to the reality of that relationship in spite of the finding of an associated Rosellinia stage by Viala⁽⁶⁾ and later by Prillieux.⁽⁴⁾ The reason for this doubt is made clear by Viala, who says:

“Nous avons essayé, par tous les precedes, d’obtinir la germination de ces sporidies sans jamais pouvoir y parvinir. La démonstration expérimentale de la relation des péritheces et des autres formes du D. necatrix manque done.”⁽⁶⁾ (p.82.)

Production of Perithecia

Recently,⁽⁵⁾ we reported on the occurrence of a highly destructive fungus on apple roots in California that so precisely resembled Dematophora necatrix, according to Hartig’s description, that we did not hesitate to name it such. From time to time since late 1933, we have collected roots from apple trees killed by this fungus and kept such material in containers under various environmental conditions in an effort to produce the ascigerous stage reported by previous workers.