DISEASES OF PLANTS. 345 



systematic removal of diseased trees (but not of diseased parts) greatly reduces 

 losses from this cause. 



Comparative tests with, sprays against leaf cast of grape, A. Bretschneideb 

 (Ztschr. Landw. Versuchsio. Osten:, 17 (1914), No. 3-^, pp. 106-118).— Con- 

 tinuing previous reports (E. S. R., 30, p. 50), the author gives some results of 

 tests made with a number of commercial fungicides. Including data as to the 

 cost of materials employed. 



Report on cryptogamic diseases of cacao at Mayumba, Vekmoesen (Bui. 

 Affr. Congo Beige, 5 (191 J,), No. 1, pp. 186-202, fig. i).— This is a brief sys- 

 tematic discussion of diseases affecting the roots, trunk, leaves, branches, and 

 fruits of cacao in this region. 



Mildew of cacao in the islands of St. Thomas and Principe, J. E. Caevallo 

 d' Almeida (Bol. Oflc. Sec. Agr. Cuha, 17 (1914), No. 3, pp. 213-216).— ^rieQy 

 describing the appearance, development, and effects of Phytophthora faberi as 

 noted in its parasitic connection with cacao, the author states that timely use 

 of Bordeaux mixture proves very helpful when it is made up in moderate to 

 high concentrations as described, but that the frequent and abundant rainfall 

 of these islands necessitates the addition of some adhesive. 



Citrus canker, II (Florida Sta. Bui. 124 (1914), PP- 25-53, figs. 9).— An ac- 

 count is given of the citrus canlier and its introduction into Florida, cause, and 

 methods of control as far as they have been determined. 



History of citrus canker, E. W. Berger (pp. 27-30). — This disease, it is 

 claimed, was first recognized early in 1913. The first serious outbreak, how- 

 ever, was noted in a nursery in Dade County in July. The spread of the 

 disease in other parts of the State as well as in the Gulf States generally is 

 briefly indicated, and a statement given regarding the means that have been 

 adopted for its control. From the evidence at hand the fungus seems to have 

 been introduced from Japan on Citrus trifoliata stock. 



Studies of citrus canker, H. E. Stevens (pp. 31-43). — In continuation of a 

 preliminary account (E. S. R., 31, p. 54) the author describes laboratory and 

 other studies on the cause of this disease and the conditions under which infec- 

 tion occurs and spreads. Successful inoculations were made in the fall of 1912 

 from material which was not then recognized as being different from the scab 

 common to many citrus species. The fungus is provisionally classed among 

 the Phyllostictas. While it is closely related to the stem-end rot fungus (Pho- 

 mopsis cit7-i), it is considered a much more virulent organism. Experiments 

 are in progress to determine the vitality of the spores and the effect of different 

 fungicides upon them. The rapidity with which the disease is spread is indi- 

 cated by the fact that in an inoculation experiment on young shoots of grape- 

 fruit from a single spot on a leaf in October, 1913, the disease had spread until 

 at the end of September, 1914, 561 infected leaves had been collected from the 

 tree. 



Eradication of citrus canker, F. Stirling (pp. 44-53). — The author describes 

 the work that has been undertaken in Florida for the control of citrus canker, 

 which is considered one of the most serious of citrus diseases. The work as 

 outlined has been carried on mostly in Dade County. As treating the infected 

 groves and nursery stock with fungicides or cutting them back and defoliating 

 has not given satisfactory results, treatment with fire is considered as prob- 

 ably the only efficient means of control. The method adopted consists of burn- 

 ing the trees, grass, and soil beneath the trees with a spray of a flaming mixture 

 of kerosene and crude oil. This is applied with a blow torch and the trees are 

 quickly burned to a crisp. In a few instances where sprouts came up from the 

 roots of the trees that had been burned no evidence was found of infection. 



