452 EXPERIMENT STATION RECORD. [Vol.36 



Streaks are found. The disease appears during the summer and fall and is said 

 to be particularly abundant in a wet year following one or two dry years. 



Cultures have been made of soil protozoa, the material having been collected 

 from diseased trees and from soil at the crown of apparently healthy trees. 

 The protozoan fauna found in connection with the diseased trees was much 

 more diverse and abundant than that from the sound ones. 



A new leaf spot disease of cherries, B. A. Rudolph {Abs. in Phytopathology, 

 6 {1916), No. S, p. 308). — A leaf sxM)t disease of sweet cherries is reported from 

 a number of points in California and Or^on. The spots produced are rather 

 large, brown, and usually definitely limited. The disease in most but not iu 

 all cases seems to originate in an insect mine. No fungus spores or fruiting 

 bodies have been found in the spots occurring in nature, but tissue plantings 

 on sterile media have repeatedly yielded a species of Alternaria. Comparisons 

 made between this fungus and A. citri and also a species of Alternaria from 

 watermelon leaves showed the three species to be very similar but to be distin- 

 guishable by certain reactions. 



Th.e action of copper stilphate on downy mildew, L. Semichon (Prog. Agr. 

 et Vit. (Ed. I'Est-Centre), 57 (1916), No. 1^ pp. 825-331; Compt. Rend. Acad. 

 Agr. France, 2 (1916), No. 11, pp. 572-S8-4 ) .— The author reports results of ex- 

 perimentation and observations regarding the great variations noted In the 

 duration of the efficacy of the reserve copper on the organs of grapevines, its 

 mode of action, the conditions of its absorption, and the possibility of obtaining 

 a greater and more certain efficacy in the copper employed. 



After a period of desiccation, the proportion of soluble copper remaining 

 available to oppose the fungus is found to be lowered in proportion to the sub- 

 sequent precipitation. A short, light rain is much less disadvantageous in 

 removing the available copper than a heavy and prolonged one. The pro- 

 portion of reserve copper on the vines which may be redissolved as the result 

 of precipitation decreases from day to day. The proportion of copper capable 

 of being redissolved may be sufficient to kill or check spore germination, or it 

 may be such as to favor spore development. The practical bearings of all 

 these facts and of others noted are discussed, among tliese the action of the 

 copper absorbed from the leaf surfaces or entering at points of injury during 

 various developmental stages of the plant. 



The action of copper salts against grape downy mildew, L. Semichon 

 (Rev. Vit., U (1916), Nos. 1134, pp. 224-230; 1136, pp. 255-261, figs. 2).— This is 

 a somewhat more extended account of the studies reported above. 



Some new strawberry fungi, F. L. Stevens and A. Petebson (Phytopathology, 

 6 (1916), No. S, pp. 258-267, figs. 26). — In continuation of a preliminary note 

 (E. S. R., 33, p. 74) in which an account was given of some rots of strawberries, 

 descriptions are given of Spfueroncemella fragarue n. sp. an-i Patellina fragaricB 

 n. sp. In addition to these species, other fungi were observed on berries in the 

 field and market, and the authors claim that Rhizopus nigricans is the cause of 

 most damage to shipped berries. 



The diseases of bananas, J. E. van deb Laat (Bol. Agr. [Sao Paulo], 11. 

 ser., No. 2 (1916), pp. 151-160, figs. 3). — This information has been noted from 

 another source (E. S. R., 31, p. 244). 



Sclerotium roLfsii on Citrus, F. A. Wolf (Phytopathology, 6 (1916), No. 3, 

 p. 302). — The author reports that during the past season this fungus caused 

 the death of seedling grapefruit in a greenhouse in Auburn, Ala. 



Cottony rot of lemons in California, C. O. Smith (Phytopathology, 6 (1916), 

 No. 3, pp. 268-278, figs. 5). — This is essentially an abridgement of the bulletin 

 previously noted (E. S. R., 34, p. 749). 



