1917] DISEASES OF PLANTS. 755 



Control of apple scab by bleaching powder, W. S. Brock and W. A. Ruth 

 (Abs. in Phytopathology, 7 (1917), No. 1, p. 76).— The authors claim that the 

 application of bleaching powder (calcium hypochlorite) to apple trees in 1916 

 reduced apple scab from 50 to 11.2 per cent without any injury to fruit or 

 foliage. 



Observations on pear blight in Illinois, F. L. Stevens, W. A. Ruth, G. L. 

 Peltier, and J. R. Malloch (Abs. in Phytopathology, 7 (1917), No. 1, p. 75). — 

 Experiments made by applying Bacillus amylovorus in suspension in water to 

 pear buds in 1915 are believed to have indicated in 1916 that the bacilli did not 

 hibeinate in the buds. Infection of the spurs from hold-over trunk cankers 

 was observed in 1916, but the organism appeared to be dead in all twig cankers. 

 Leaves are said to be at no time naturally infected from the exterior, and on 

 June 1 blades and pedicles could not be inoculated through the fruit while pedi- 

 cles were still susceptible. The application of Bordeaux mixture is said to have 

 controlled the floral infection without reducing the set of fruit. 



Studies on peach yellows and little peach, M. A. Blake, M. T. Cook, and 

 C. A. Schwarze {Abs. in Phytopathology, 7 {1917), No. 1, pp. 76, 77).— The re- 

 sults of investigations on these diseases are briefly described, and it is claimed 

 that pits from diseased trees failed to germinate. Budding experiments with 

 diseased buds indicate that the appearance of the disease in young trees varies 

 with the source of bud wood. 



Second progress report on investigations of leaf spot of cherries and plums 

 in Wisconsin, G. W. Keitt {Abs. in Phytopathology, 7 {1917), No. 1, pp. 75, 

 76). — In continuation of investigations on the leaf spot due to Coccomyces 

 hiemalis (E. S. R., 36, p. 149), the author reports having found that the trouble 

 is satisfactorily controlled by the use of Bordeaux mixture of various strengths 

 and lime-sulphur. Atomic sulphur, barium-sulphur, and self-boiled lime-sulphur 

 in parallel applications did not control the disease satisfactorily. 



A new disease of cacao, M. Tubconi {Atti R. Accad. Ldncei, Rend. CI. Sci. 

 Fis., Mat. e Nat., 5. ser., 26 {1917), I, No. 1, pp. 75-78). — In a preliminary note 

 the author records the occurrence on Thcobroma cacao, in the botanical garden 

 at Pavia, of a leaf spot fungus described as a new species under the name Phy- 

 salospora theobroniw, and of two associated fungi also described as new, which 

 are given the respective names, Stachylidium thcobrovia; and Helrninthosporium 

 theobromw. 



Diseases of chayote, R. RamIrez {Bol. Dir. Agr. [Mex.], 2 {1916), No. 2, p. 

 58, pi. 1).—The chayote is subject to injury by Cuscuta, Helix humboldtiana, 

 and a disease affecting leaves and fruits associated with a Sphserella presumably 

 as a primary agent and with several fungi named as secondary. 



Mango disease in Yucatan, R. RamIrez {Bol. Dir. Agr. [Mex.], 2 {1916), 

 No. 2, pp. 59, 60, pis. 2). — A disease attacking branchlets, flowers, and fruits of 

 mango, also other plants, is described as due to Glxeosporium, mangiferw. 



Additional suggestions on treatment of hazel blight, M. B. Waite {Amer. 

 Nut Jour., S {1915), No. 6, p. 97). — The same treatment is recommended for 

 hazel blight that has been found successful with black knot of plum and cherry, 

 which yields to cutting out the blighted portions in February or early March 

 before the spores have matured, and applying a dormant spray of Bordeaux 

 mixture. Eradication of wild hazel is also considered important. 



Winterkilling, sun scald, or sour sap of pecans, S. M. McMurran {Amer. 

 Nut Jour., S {1915), No. 5, p. 82). — This is a descriptive account of the influence 

 of cold weather succeeding warm days in November as causing injury or death 

 to pecan trees which had renewed growth in the fall after a serious check due 



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