H. WORMALD 103 



affected trees fruiting spurs were killed soon after the flowers opened, 

 the flowers and leaves became withered and the fungus penetrated into 

 the bark of the branches. 



One of the most valuable contributions to our knowledge of the 

 Brown Rot MoniUas is a paper by Woronin(2;5) published in 1899; in 

 it he not only supplied evidence in favour of his contention that Sclero- 

 ti)iia fnictigena and S. cinerea were distinct species and could be dis- 

 tinguished even in the Monilia (or conidial) condition, but also used the 

 two forms in his inoculation experiments using, apparently, pure strains^ 

 of these fungi. With regard to his results when the flowers of the apple 

 were inoculated, he found that the conidia of S. cinerea germinated on 

 the stigmas and attacked the styles slightly tut the germ-tubes were 

 unable to penetrate further into the flower. The germ tubes of the 

 conidia of S. fructigena on the other hand grew out into all parts of the 

 flower and then into the pedicels and leaves, the latter gradually be- 

 coming withered. From these results he states emphatically, "Meine 

 Experimente beweisen ausserdem, dass die Laubdiirre bei den Aepfeln 

 nur durch Sclerotmia fructigena verursacht werden kann." 



In 1900 Aderhold(i) records having received specimens of apple twigs 

 which, from their appearance, he believed had been destroyed by "fire- 

 blight," the bacterial disease which ravages pear and apple trees in 

 America. The affected shoots contained a white mycelium which when 

 cultivated in hanging drops produced a Penicilliu'm-Yi^Q fructification^ 

 which he considered was the conidial form of a MoUisia. Later how- 

 ever (2) having found that shoots killed during the previous year bore 

 Monilia pustules he attributed their death to the action of M. cinerea 

 and concluded that the form previously observed was of secondary origin. 



Muller-Thurgau(i5) in the same year describes a similar disease of 

 apples and pear trees but refers the causal organism to M. fructigena. 



Aderhold and E.uhland(4) in 1905 confirmed the work of Woronin 

 in that they found that inoculation of apple flowers with Sclerotinia 

 cinerea led to a weak infection while Sclerotinia fructigena readily pro- 

 duced the death of the blossoms. 



Eriksson (8) in 1913 figured and described a canker-like disease of 



^ Woronin is not quite clear on this point; on p. 18 he writes of "zahlreiche, reine. 

 streng controlirte und moglichst variirte Impfversuche mit diesen beiden Pilzen," but 

 whether his "reine Impfversuche" were made from cultures growing on previously 

 sterilised media is not stated. 



^ From the description and figures it would appear that these Penicillium-Vike fructifi- 

 cations consisted of "sporidia" or "microconidia" of the Monilia, as the production of 

 these bodies is readily induced in artificially prepared cultures of the Brown Rot fungi. 



