330 



Bulletin 263. 



improbable that this disease was referred to by Galloway ('89) as Black 

 Knot of the grape, and said to be due to frost injury; by Fletcher ('89") 

 also as Black Knot; by Woodworth ('92) as Root Knot or commonly 

 as Black Knot. The material which Fletcher examined was sent to 

 Dr. W. G. Farlow of Harvard University, who suggested that "the 



trouble, however, is climatic rather 

 than fungous," and perhaps due 

 to frost injury. The frost-injury 

 idea is a very common one. 

 Growers commonly refer to the 

 disease as Side Arm, Dead Arm 

 or Black Knot. 



In European literature, we find 

 numerous references to diseases 

 of the vine. Besides root and stem 

 diseases ascribed to Dematophora, 

 Armillaria, and the like, there are 

 a number of so-called physiologi- 

 cal diseases. These are described un- 

 der various captions such as Fol- 

 letage, Chlorosis, Rougeot, Brous- 

 sins, Exotoses, Fongosites, or Tu- 

 bercoli. Viala ('93) has de- 



scribed and illustrated a disease, 

 Broussins (excrescences), as due 

 to frost injury. From descrip- 

 tions of general appearances one 

 might easily believe that near- 

 ly any of the above were the 

 same disease as the one with 

 which we are dealing. Some of 

 the illustrations, especially those of Viala, might be readily used to 

 illustrate this paper, since the points of similarity are so great. 



('89) Galloway, B. T. A record of some of the work of the Division. Part II, 



Section of Vegetable Pathology. U. S. D. A., Bot. Div. Bull. 8:63. 1889. 

 ('89) Fletcher, Jas. Report of the Entomologist and Botanist. Rept. Can. Exp. 



Farm, 1889, p. 87. 

 ('92) Woodworth, C. W. Root Knots on Fruit Trees and Vines. Univ. Cal. 



Agr. Exp. Sta. Bull. 99:1-4, 1892. 

 ('93) Viala, P. Les Maladies de la Vigne, Troisieme edition 1893. I. c. p. 489- 



490, Figs. 227-232. 



Photo. Aug. 20, 1908 



Fig. 46. — Niagara. Enlarged view of 

 an excrescence seen in Fig. 45 {nat- 

 ural size) 



