DISEASES OF PLANTS. 45 



Examples of disease control in practical operations, R. Schandee {Jahres- 

 ber. Ver. Angew. Bot., 9 {1011), pp. 26-38). — This is an account of work done 

 in exposition of methods of combating diseases and pests affecting fruit trees, 

 the American gooseberry mildew, etc., with a view to encouraging the wider 

 adoption and use of such methods. The important practical difficulties in the 

 employment of the hot-water treatment for loose smut of wheat are said to limit 

 greatly its practicability. 



Report of the pathologist, J. R. Johnston (Porto Rico Sugar Producers' 

 Sta. Rpt. 1912, pp. 23-28). — The work of the pathologist was continued along 

 the lines suggested in his first report (E. S. R., 26, p. 143), being confined in the 

 main to diseases of the sugar cane. 



Of the sugar cane diseases in Portx) Rico those caused by root fungi are said 

 to be the most common and destructive. There are two main types of root 

 diseases, one characterized by the tight binding of the leaf sheaths, and the 

 other by the branching, white mycelium. 



The rind disease occurs in Porto Rico and appears to have a close relation 

 to the climatic conditions and to the presence of the moth stalk borer. 



The use of Bordeaux mixture for treating seed cane has been recommended, 

 and the author calls attention to the fact that in times of drought the treatment 

 is of unquestionable value, while in a good gei-minating season it may show 

 little effect other than hastening germination. 



A disease due to Cercospora vaginw, causing the red rot of the leaf sheath, 

 was investigated, and experiments were carried on to determine the effect of the 

 disease on the gi'owing of young cane. Shoots from two lots of cuttings, one 

 diseased and the other apparently free from disease, were examined, and, 

 absolutely no difference could be detected in the two lots. 



A new disease is said to have made its appearance, which so far has been 

 limited to the variety known as D 117. It is characterized by the appearance 

 of withered tips or dry, brown areas on the leaf blade. Several fungi have 

 been found on the dead or dying parts of the cane leaves, but they are not 

 believed to be strictly parasitic. 



The author, in cooperation with the chemist of the federal station at Maya- 

 guez, is investigating a form of chlorosis of cane, particularly in regard to the 

 presence of various fungi. 



The report concludes with a brief account of laboratory experiments and 

 cultures of a number of fimgi known to attack the sugar cane. 



Report of the Union plant patholog-ist and mycologist for 1911, I. B. P. 

 Evans {Union So. Africa Dept. Agr. Rpt. 1910-11, pp. 257-266, pis. 19). — During 

 the period covered by this report the investigations consisted largely of studies 

 on the fnngiis flora of South Africa, a bacterial disease of mangoes, brown 

 rust of maize, a fungus disease of bagworms, crown gall of plants, silver leaf 

 of stone fruits, and fungi on wattle and wattle timber, together with experi- 

 ments for their control. 



The bacterial disease of mangoes is said to have been reported from a num- 

 ber of localities, and all parts of the tree seem to be subject to attack. Upon 

 the leaves small, dark, angular spots are formed, and on the stems discolored 

 areas, accompanied by longitudinal cracks, are found. The peduncles and 

 pedicels are affected to such an extent that they become dark and the fruit 

 becomes detached and falls to the ground. A bacillus has been isolated from 

 infected tissues and the disease reproduced* by means of inoculation experi- 

 ments. Spraying has up to the present not proved of any use in combating 

 this trouble. 



In a study of the brown rust of maize {Puccinia maydis), the author con- 

 firms other observations, showing that the fungus on maize is associated with 



