W or maid, — ‘ Brown Rot ’ Diseases of Fruit Trees. 363 
and this, together with the fact that many workers still refuse to recognize 
that there are at least two distinct species of Monilia causing Brown Rot 
diseases, renders much of the work valueless as scientific records. 
II. Historical. 
In previous papers where the present writer (1917-18) described two 
specific diseases, on apple trees and plum trees respectively, literature was 
cited which related more particularly to the two diseases or to results obtained 
during the course of experiments connected with them, and no attempt was 
made to obtain a complete review of the papers dealing with those diseases 
of fruit trees caused by species of Monilia. Since the object of the present 
article is to show the relation which the two diseases bear to one another 
and to other Brown Rot diseases, a more general historical survey of our 
knowledge of the subject is desirable. 
The earliest record of the occurrence of a Monilia on fruit appears to 
have been one by Persoon, who, finding a fungus producing tufts of 
moniliform chains of conidia on the decaying fruits of Pyrus communis , 
Primus domestica , and Amygdalus persica in the year 1796, named it 
Torula fructigena. Five years later he changed the name to Monilia 
fructigena , and this is the name which is still usually applied to the conidial 
stage of the fungus. The former name was, however, frequently used for 
some time by certain workers, e.g. Albertini and Schweinitz (1805), Fuckel 
(1869), Saccardo (1873), Rabenhorst (1844-1853). 
In 1817 Kunze and Schmidt named the fungus Oidium fructigenum , 
and this name was retained by Ehrenberg (1818), Fries (1829), Duby 
(1830), Cooke (1871), and Worthington Smith (1885). Other names by 
which it has been known are Acrosporium fructigenum , used in 1822 by 
Persoon himself, but not adopted by other botanists, Oospora fructigena and 
O. Candida , as used by Wallroth (1833), and Oidium W allrothii, by von 
Thiimen (1875), who, however, in 1879 changed it to O. fructigenum. 
Schroter, in 1893, from analogy with other species of Monilia producing 
an ascigerous stage, concluded that M. fructigena was the conidial stage of 
an ascomycete, and transferred it therefore to the genus Sclerotinia ; in 
this connexion Prillieux (1897) wrote, ‘ ce n’est que par analogie que Ton 
peut regarder ce parasite comme une Pezize reduite a sa forme imparfaite 
de fructification 5 . In 1903 Ritzema Bos proposed that the fungus should 
be referred to the genus Stromatinia ; this name has not been generally 
accepted, though adopted by Delacroix and Maublanc in their ‘ Maladies 
des Plantes cultivees \ 1 
The apothecial stage of Monilia fructigena was discovered on the 
Continent by Aderhold in 1904, thus confirming Schroter’ s conclusion 
regarding the ascomycetous nature of the fungus. Norton (1902) had two 
1 Loc. cit., vol. ii, p. 255. (Paris, 1909). 
