DISEASES OF PLANTS. 447 



Descriptions are given of Glocopeziza tunk-uUi n. sp. and Hyalopus gcophilus 

 n. sp.. wbicli have been found occurring in the soil of tobacco seed beds, from 

 which they jittacli the tobiicco plants, sometimes causing serious loss. 



A review of investig'ations of the mosaic disease of tobacco, together with 

 a bibliog'raphy of the more important contributions, H. A. Allard {Bui. 

 Toncy Bat. Club, Jtl (1914), ^'o. 9, pp. 435-45S). — This review and bibliography 

 of mosaic disease of tobacco, under its various names, covers investigations from 

 ]SS6 to 1914, concluding. with the author's own report already noted (E. S. R., 

 30, p. 450). 



Fire blight, W. H. Brittain (Brit. Colmnhia Dcpt. Agr., Hort. Branch Circ. 

 23 {1915), pp. 10, figs. 2). — ^A popular description is given of the fire blight of 

 pears, apples, and occasionally quinces, caused by Bacillus amylovorus, with 

 directions for its control. In addition to the trees mentioned above it is known 

 to affect also hawthorn, June berry, and mountain ash. 



Fungus and other diseases of the apple and pear, G. P. Darneix-Smith and 

 E. MACKINNON {Agr. Gaz. N. 8. Wales, 25 {191J,.), No. 12, pp. 1037-lOU, pls. 6; 

 26 {1915), Nos. 1, pp. 51-57, pis. 2; 2, pp. 105-113, pis. iO).— Descriptions and, 

 so far as definite methods are known, suggestions for control are given of 

 canker, bitter rot, Phyllosticta canker, Nectria canker, blight, mildew, crown 

 gall, bitter pit, apple scab, pear scab, black rot, spray injury, frost band, 

 chlorosis, etc. 



The toxic action of sulphurous anhydrid on olive blooms, L. Petri {Studi 

 snlle Malattie deiroiivo, VI. Rome: R. 8taz. Patol. Veg., 1914, pp. 65-76, pi. 

 1, fig. 1). — Continuing previous studies (E. S. R., 30, p. 245), and noting here 

 the results of tests carried out under controlled conditions as regards tempera- 

 ture, moisture, and sulphur dioxid content, the author states that this gas in 

 the concentration of about 1 : 16,000, while not necessarily hurtful to other 

 parts of the plant, is directly and rapidly injurious to the olive stigma at a 

 relative humidity of 75 to SO per cent, this effect, however, being lessened by 

 relative dryness of the stigmatic papillae. Pollen shows much higher resistance 

 to this gas, sepals and petals showing either about the same resistance as do 

 the young leaves, or somewhat less. 



The fungus of peach mildew, N. Woronichine {Bui. Trimest. Soc. Mycol. 

 France, 30 {1914), ^o. 3, pp. 391-401). — Discussing related literature and de- 

 tailing his own studies in regard to Splucrotlieca pannosa, causing mildew of 

 roses and peaches, the author concludes that the biological and morphological 

 divergencies noted are sufficiently great to warrant the separation of this 

 species into the varieties rosce and persicw, corresponding, respectively, to the 

 host attacked by each, 



A disease of gooseberry new to Italy, C Greppi {Riv. Patol. Veg., 7 {1914), 

 No. 4- PP- 97-99). — This is a brief note on the outbreak of Sphwrotheca mors'-urvw 

 in England and parts of Europe, it appearing at points in Italy in 1913 and 

 1914, with discus.sion of measures for its control. 



The infiuence of the medium and of atmospheric factors upon the develop- 

 ment of downy mildew, L. Moreau and E. Vinet {Prog. Agr. et Vit. {Ed. 

 VEst-Centre), 35 {1914), No. 34, pp. 225-235).— The authors detail and discuss 

 recent observations on downy mildew of the grape, regarding variations in 

 virulence of the parasite and in susceptibility of the host, and the influence 

 of the medium and of atmospheric agents upon the development of the fungus. 

 They discuss also, in this connection, the significance as regards spraying, etc., 

 of these considerations and of recent observations on the temporal and causal 

 relations of the outbreaks with the other phenomena. 



