448 EXPERIMENT STATION RECORD. 



The authors append to this report of their own investigations brief abstracts 

 of a long list of contributions made by others on the subject of potato leaf-roll 

 disease in 1911. 



Experiments with Bordeaux mixture as a cane dip, A. H. Rosenfeld {In- 

 ternat. Sugar Jour., 1^ (1912), No. 161, pp. 255-263). — The author describes 

 experiments in dipping sugar cane in Bordeaux mixture for the prevention of 

 diseases, and also the effect of the fungicide on the germination and growth of 

 the plants. Ttie experiments were divided into 2 series in which normal 

 strength and double strength Bordeaux mixture was used, one lot of seed cane 

 in each series being left in the solution for 1 hour and the other lot soaked for 

 24 hours. The cane was planted and observations made on its germination and 

 subsequent growth from time to time. 



Inspection showed that cane which had been dipped for 1 hour in the Bor- 

 deaux mixture gave better results than the untreated lot, while that which had 

 been soaked for 24 hours in the fungicide gave yields less than the checks. 

 The smallest number of stalks per row was obtained from the lot dipped for 

 24 hours in double fetrength Bordeaux mixture. 



Fruit trees and black spot canker, J. F. Carpenteb [Brit. Columbia Dept. 

 Agr. Bui. 3Jf, 1911, pp. ij, figs. 5). — This disease, known also under the names 

 anthracnose, sour sap, etc., in British Columbia since 1901 and in neighboring 

 portions of the United States 10 years earlier, is here described, and the com- 

 parative susceptibility of several varieties of trees is discussed. 



The disease is said to be due to a parasitic fungus, called Macroplioma curvi- 

 spora by Peck and Glccosporium malicorticis by Cordley. Spore-bearing pus- 

 tules on the surface mark the course but not the full progress of the disease. 

 The fungus may enter apparently without previous breaches in the bark, but is 

 favored by such injury and spreads in the cambium layer and later in the bark 

 to a corresponding extent, producing broad, deep, and sometimes incurable 

 wounds, sapping the vitality of the trees, killing branches, stunting growth, 

 and materially decreasing crop returns. The spores are contained in a gela- 

 tinous mass which dissolves in water, permitting their escape, but not to any 

 very great extent until wet weather furnishes favorable conditions, usually 

 after the appearance of the autumn rains. It seems that infection occurs most 

 freely during November and December. 



For control of this disease, comparative dryness and freedom from injury are 

 desirable. Proper elevation, drainage, spacing, pruning, and care in cultivation 

 are insisted upon. To prevent infection of the trees by spores w^hen present, 

 Bordeaux mixture or lime-sulphur wash is recommended. The spraying should 

 be done once early in the fall before the rains set in, and repeated just after 

 the fall of the leaves. 



A new canker-producing fungus, A. Potebnia {Ztschr. Pflangenlcranlc, 22 

 {1912), No. 3, pp. 129-lJf8, pis. 3). — A disease of Pyrus paradisiaca was investi- 

 gated by the author and by him attributed to the activity of a fungus formerly 

 known under the name Phacidium discolor but by the author classed as a new 

 genus and named PliacidieUa discolor. A detailed discussion is given of the 

 forms, habits, relationships, and ravages of this fungus, which is found on both 

 dry and living twigs of several species of Pyrus, having been noted, at Kharkof, 

 Russia, and at Liege, Belgium. 



Diseases of raspberry and loganberry {Jour. Bd. Agr. [London], 19 {1912), 

 No. 2, pp. 12.'i-126, pi, 1). — A description is given of Ilendersonia ruM, which is 

 responsible for serious injury to raspberries and loganberries, and Ascochyta 

 pallor, which occurs as a parasite of raspberries, roses, etc. 



The first fungus attacks the stems diiring the summer when the young growth 

 is tender, and as a rule lurid red or purplish patches appear on the stem. 



