no 



are troublesome to graphs. The C. viticoluni' occurs on Vitis labnisca, 

 and V. vinifera. A species was common in New York, in Clinton/ 

 according to Mr. Fairchild. C. roeskri, Call, on the European culti- 

 vated grape ( Viiis vinifera) in Europe.' The Apple Scab {Fusicladiiim 

 dend'-itici/m) is a fungus closely related to the plum fungus," and without 

 doubt will seriously threaten plum culture. 



The spots are visible in half ripe plums as small pale greenish 

 or yellowish patches not larger than a pin head. They increase in size, 

 l)ecoming in some cases half an inch across. S jme of the older spots 

 may become confluent, forming one large more or less radiating patch. 

 Patches may be formed in nearly mature plums. In old specimens 

 which have been kept moist for some time the spo;; becomes darker in 

 colour, almost black, more irregular and raised. 



Microscopic examination of the affected portions of the plum shows 

 a ne.iily colourless mycelium creeping over tke surface or vegetating 

 between the cuticle and the remainder of the epidermal cells. In the 

 darker portions occur the septate hyph;e, these occasionally come 

 through the cracks in the cuticle. In older material a dense stroma of 

 shirt brown hyphae appears between the cuticle and cellulose layers of 

 the epidermal cells. The small spores are oval in shape, pointed at 

 the end and usually two-celleJ, and are borne at the end of the 

 conidiophore, or laterally. They germinate readily when placed in 

 water. 



The chief injury caused by this fungus is the cracking of the 

 plums, allowing Monilia fnictigeiia a chance to work. The injury, 

 however, does not extend much beyond the [)oint of attack and only a 

 small number of the plum cells become brown. The fungus, no doubt, 

 also, checks the development of the plum, and in the severer cases it 

 causes a shrivelling of the fruit. The fungus seems to occur on all 



3. Soraner Pflanzen Krankheiten, Vol. II., p. 401. 



4. Jour, of Mycology, Vol. VI., p. 99. Scribner, Diseases of the i^rape vine. 

 " Bull. 2, Dept. of AgricuL, Rep. 1886, p. 3. Galloway, Jour, of xMycology, 



Vol. V, p. 93. 



5. Soraner Pflanzen Krankheiten, Vol. I., p. 401. 



6. See Bailey. The cultivated native plums and cherries, Bull. 38, Cornell 



University, Agrl. Experiment Station, p. 54. Pummel, four, of Mycology, 

 Vol. VII., p. 99. 



