1910] DISEASES OF PLANTS. 159 



species under Hie names Bacterium cattlc\ja\ /;. Krameriani, B. brinxiunum, 

 J.ik ill us pollacii, and B. fanutianus. 



More about rose diseases, L. M. .Massky (In The American Rose Annual. 



Harritburg, I'a.: Amer. Rose 800., 1918, pp. 63-71, fig. l).— This is the a ad 



report made by the author od this iDvestigation (B. s. k., :'>7, p. 863). 



Crown canker, an important rose disease first observed by the author in 

 1916, is now known to exist in Missouri, Pennsylvania, Indiana, Michigan, 

 Massachusetts, and New York, seedlings and grafts of different ages and 

 numerous varieties being affected. It has not been observed on outdoor plants. 

 t'ylindroclailium aooparium is said to be the cause of the disease, which may 

 prove to be the most important disease of roses under glass. Moisture appears 

 to be an Important factor. Control experimentation is in progress. 



In case of black spot (Diplooarpon rosce), commercial concentrated lline- 

 B&lphur made up to a strength of 1 : 50 proved more efficacious than ammonlacal 

 copper carbonate and probably as much so as Bordeaux mixture and sulphur- 

 arsenate dust, but it is said to discolor the foliage almost as much as Bordeaux 

 mixture In the nursery, sulphur-arsenate permitted the lowest rate of in- 

 fection, 7. 60 per cent, Bordeaux mixture 8.51, lime-sulphur 24.43, Hammond's 

 copper solution 1:100, 37.77, and untreated 80 per cent. Experiments were 

 conducted at Ithaca, N. Y., for the same disease. Results of all these tests, 

 taken with others noted as applying to powdery mildew, are thought to warrant 

 the opinion that the sulphur-arsenate dust mixture, when properly applied, 

 affords the most efficient means of control of the two diseases said to be most 

 injurious to roses. 



A study of heart rot in western hemlock, J. R. Weir and E. E. Hubert 

 (U. S. Dept. Ayr. Bui. 722 (1918), pp. 37, figs. 13).— The western hemlock is 

 Raid to be subject to a large percentage of decay, due almost entirely to the 

 fungus Echinodontium tinctorium, which causes a stringy brown rot of the 

 heart wood extending to all parts of the trees. The fungus is said to enter 

 mainly through branch stubs, and the decay extends up and down the heart- 

 wood until all the susceptible heartwood is attacked. The extent of the injury 

 was found to increase with age. 



As means of control, the authors suggest cutting the infected trees and de- 

 stroying by fire all infectious cull material, and all infected trees left standing. 



Tumors of the maritime pine, J. Dufrenoy [Compt. Rend. Acad. Sci. 

 [Paris], 166 (1918), No. 8, pp. 355, 356).— In the forest of Arcachon, the mari- 

 time pine shows a large number of tumors on trunk or root. These are here 

 described as to external and internal characters and relations, some of them 

 recalling those of crown gall as noted by Smith and others (E. S. R., 25, p. 243). 



The reactionary cells and neighboring ones contain abundant microorganisms 

 which are Gram-negative but colorable by gentian violet or methylene blue. 

 Both the diseased tissues and the exuding resin may also show the presence of 

 a very fine mycelium. 



Root and stem tumors appear to be due to different bacteria which require 

 further study. These bacterial trunk tumors of the maritime pine are said 

 to be different from those of the Aleppo pine, inasmuch as the parasites in the 

 former case are intracellular and the injury develops away from the base of the 

 tree. 



The white pine blister rust and the chestnut bark disease, E. P. Meinecke 

 (Mo. Bui. Cul. Com. Hort., 6 (1917), No. 7, pp. 268-279, figs. 9).— This is a brief 

 discussion of the history, characteristics, effects, and control of white-pine 

 blister rust (Peridcrmium strobi, Cronartium ribicola) aud chestnut bark dis- 

 ease (Endothia parasitica). 



