DISEASES OF PLANTS. 543 



tion of iron compounds, the author suggests the utilization in connection with 

 grape chlorosis of certain iron hearing soils widely distrihuted in France. 



On the proportion of iron sulphate used against white rot of grapevines, 

 M. Blunno (RiJt. Austral. Assoc. Adv. Sci., IS {VJll), pp. 5U2-5G6). — The 

 author reports his experience with white rot of the root system of grapevines, 

 associated with Dematophora nccatrix. Carbon bisulphid applied at the rate 

 of 1 oz. i)er vine, divided into 5 partial injections, 6 or 8 in. from the stem, 

 was effective during the first stage of the infection, but could not destroy the 

 foci of infection represented by roots of once existing trees, and repeated and 

 stronger doses endangered the vines. Ferrous sulphate applied once annually 

 for 3 successive years at the rate of 8, IG, and 10 oz., respectively, to each vine 

 was sufficient to restore all but 2 vines, in which the chlorosis yielded to a 

 further and slightly modified treatment. This salt is thought to act not only 

 as a fungicide, but as a vigorous stimulant to growth. 



The present status of the defensive treatment for cacao canker in Samoa, 

 K. Fbiederichs {Tropenpflanzer, 17 {1913), No. 10, pp. 571-578).— The author 

 claims that Bordeaux mixture applied carefully and thoroughly in August, 

 October, and December is safely protective against cacao canker ascribed to 

 Phijtophihora faberi, if in connection therewith care is taken to destroy all 

 parts of badly infected trees and certain insects mentioned. 



Gummosis in roots and pods of Acacia, L. Lutz (Bui. Soc. Bot. France, 

 60 {1913), No. 5, pp. 522-32^).— Pursuant to a previous report (E. S. R., 7, 

 p. 468), the author states that the succession of phenomena characteristic of 

 the progress of gummosis in Acacia is the same in the roots as in the trunk, 

 but in general of later occurrence in the former, as marked by clogging or 

 obliteration of the vessels. Although lesions appeared on the pods, the seeds 

 were not affected. 



Twig canker on black birch, C. Hartley (Phytopathology, 3 (1913), No. 4, 

 pp. 248, 249). — During the winter of 1910 a twig canker was reported as doing 

 serious damage to Betula lenta in the New York Zoological Park. The twigs 

 developed considerable swellings and the part beyond the swelling died. An 

 examination of affected material showed the presence of Sphseropsis, Cytospora, 

 and Myxosporium, and inoculation experiments were carried on with the differ- 

 ent fungi. 



The results showed some infection, but further inoculations on young rooted 

 trees gave negative results. This is believed to Indicate that the Sphaeropsis, 

 which seemed to be the most common species, is parasitic only under certain 

 conditions, and that it is improbable that these fungi were concerned in caus- 

 ing the swollen cankers characteristic of the disease. 



The chestnut bark disease, H. Metcalf {Jour. Heredity, 5 {1914), ^o. 1, 

 pp. 8-18, figs. 8). — The author gives an account of the chestnut bark disease, 

 due to Endothia parasitica, suggesting its possible introduction from the Orient, 

 and describes its distribution, manner of infection, symptoms, etc. For the 

 control of the disease it is thought that probably the breeding of immune or 

 highly resistant varieties will be necessary. 



The chestnut bark disease on chestnut fruits, J. F. Collins {Science, n. 

 ser., 38 {1913), No. 989, pp. 857, 858).— The author reports the observation on 

 nuts and burs of the chestnut of reddish-brown pustules resembling those of 

 Endothia parasitica. Portions of the diseased fruits were successfully inocu- 

 lated into the bark of chestnut trees, producing typical infection. 



The results of the inoculations indicate that the disease was present on or 

 in the nuts and burs collected, and while diseased nuts are not likely to often 

 reach the market, yet the possibility of the dissemination of the disease in 

 this manner should not be overlooked. 



