ASCOMYCETES 187 



VII. BROWN ROT OF STONE FRUITS 

 Sclerotinia fructigena (Pers.) Schroet. 1 



Aderhold, Rud. Ueber eine vermuthliche zu Monilia fructigena Pers. ge- 



horige Sclerotinia. Ber. d. deut. bot. Ges. 22 : 262-266. 1904. 

 Humphrey, J. E. On Monilia fructigena. Bot. Gaz. 18 : 85-93. pi. 7. [893. 

 Norton, J. B. S. Sclerotinia fructigena. Trans. Acad. Sci. of St. Louis 12: 



91-97. pis. 1 8-3 1. 1902. 

 Quaintance, A. L. The Brown Rot of Peaches, Plums, and Other Fruits. 



Ga. Agl. Exp. Sta. Built. 50: 237-269. Jigs. i-g. 1900. 

 Smith, Erw. F. Peach Blight, Monilia fructigena, Pers. Journ. Myc. 5 : 



123-134. pis. 3,6. 

 Sorauer, P. Erkrankungsfalle durch Monilia. Zeitsch. f. Pfianzenkr. 9 : 



225-235. pi. 4. 1899. 

 Wehmer, C. Monilia" fructigena Pers. (= Sclerotinia fructigena m.) und die 



Monilia Krankheit der Obstbaume. Ber. der Deut. Bot. Ges. 16 : 298- 



307. pi. 18. 1898. 

 Woronin, M. Ueber Sclerotinia cinerea und Sclerotinia fructigena. Mem. 



de l'Acad. imp. d. Sci. de St. Pe"tersbourg. Vll^-Sdr. Phys.-Math. CI. 



10(5): 1-38. pis. 1-6. 1899. 



The fungus causing the brown rot of fruits has been known 

 botanically for half a century, but its great economic importance 

 has only been appreciated during the past twenty years. It is now 

 a well-known disease wherever the peach is grown throughout 

 Europe and America. The conditions under which great injury 

 results are, however, not general in all the countries named ; and 

 therefore it may be very destructive one year and of relatively 

 slight importance the following season. Whether warm or cool, 

 moist weather is favorable to the spread of the disease, but the 

 muggy weather of midsummer is particularly disastrous to the 

 stone-fruit crop, on account of the rapid spread of the disease 

 under such conditions. 



1 Under this title is discussed the widespread rot of stone fruits. Two species 

 of Sclerotinia may, according to the work of Woronin, be distinguished as caus- 

 ing somewhat different types of disease ; these species are Sclerotinia fructigena 

 and Sclerotinia cinerea. It is claimed that there are no observable differences in 

 the mycelium of the two species, but that differences are evident in the color of 

 the spore masses and in the susceptibility of hosts to the two forms. In Sclero- 

 tinia fructigena the spores are described as light brownish-yellow, or ochraceous, 

 while in the other they are invariably gray. Moreover, in the former the spores 

 are larger, averaging 20.9 X 12.1/t, while the latter average 12. 1 x 8.8 ^t. Sclero- 

 tinia cinerea is said to be most abundant on the common stone fruits, whereas 

 Sclerotinia fructigena is also found on pomaceous fruits. The above view does 

 not appear to be that generally held by American pathologists, and it is not uni- 

 formly accepted in Europe. We shall, therefore, use the name Sclerotinia fructi- 

 gena to designate this rot-disease of diverse stone fruits. 



