1916] DISEASES OF PLANTS. 547 



.)i5). — Against Corynespora melonis, causing a spread of leaf rust in Germany, 

 a 1 per cent Bordeaux spray for tlie young plants is recommended as pre- 

 ventive. Seed should be kept for 1.5 hours in 0.5 per cent formalin before 

 sowing. After the outbreak has occurred, it is necessary to destroy completely 

 all plants with their fruits, or to remove them to some unused portion of the 

 field which can be left uncultivated for several years. 



Ginseng diseases and their control, H. H. Whetzel, J. Rosenbaum, J. W. 

 Brann, and J. A. McClintock {U. S. Dept. Agr., Farmers' Bui. 736 {1916), pp. 

 23, figs.26). — This describes in a popular way the diseases of ginseng and their 

 control, technical descriptions of the different diseases having been previously 

 noted (E. S. R., 27, p. 649). 



The neck rot of white onions, J. G. Humbert {Mo. Bui. Ohio Sta., 1 {1916), 

 No. 6, pp. 116-180, fig. 1). — Results from an investigation on the neck rot of 

 white onions, due to Sclerotium cepivorum, are given. This disease is said to 

 have been the cause of heavy loss in stored onions, and experiments for control, 

 including sanitation methods and fumigation with formaldehyde gas, have been 

 carried on with some success. Dump heaps of rotting onions should not be 

 permitted, and crates and storage houses should be disinfected if the new crop 

 is to be kept free from disease. 



This disease has been confused with smut, but this attacks the growing 

 onions, while the neck rot is apparently a trouble which destroys the mature 

 onions in storage. 



Potato dry spot in Java, A. Rant {Teysmannia, 26 {1915), No. 5, pp. 285- 

 287, pis. 2). — A disease of potato leaves is described which is thought to be 

 identical with early potato blight due to Alternaria solani. 



Boot rot of tobacco {Wisconsin Sta. Bui. 268 {1916), pp. 17, 18, figs. 2).— A 

 brief account is given of the work of J. Johnson on the rooot rot of tobacco, 

 due to Thielavia basicola, and methods for its control. Since certain strains 

 of tobacco have been found to differ widely in susceptibility to the disease, an 

 attempt is being made to develop a resistant type which will be of high quality 

 and also able to grow on worn-out tobacco fields. Until such a type is secured, 

 it is recommended that growers sterilize the soil of seed beds or plant on soil 

 that has not grown tobacco in recent years. 



Bacterial rot of tomato, V. Peglion {Atti R. Accad. Lincei, Rend. CI. Sci. 

 Fis.. Mat. e Nat., 5. ser., 24 {1915), II, No. 3, pp. 157-160).— A rot of tomato 

 appeai-ing in May, 1914, was reproduced in characteristic form by inoculation 

 with a bacterium isolated from the decayed fruits. The organism appears to 

 lose quickly much of its virulence in artificial substrata. 



Root rot of fruit trees, J. J. Thornbeb {Arizona Sta. Rpt. 1915, p. 530). — 

 In continuation of work by McCallum, discontinued in 1910, the author made an 

 examination of orchards where root rot was causing serious loss. It is consid- 

 ered that more than one fungus is responsible for root rot, and in the absence 

 of definite information, no positive methods for control can be given. This in- 

 vestigation is to be continued. 



Study of Coniothyrium pirina, Phyllosticta pirina, and C. tirolense, Elisa 

 MuTTo and G. Pollacci {Atti R. Accad. Lincei, Rend. CI. Sci. Fis., Mat. e Nat., 

 5. ser., 24 {1915), II, No. 1, pp. 40-42). — Evidence is adduced to show that the 

 fungus denominated C. pirina by Sheldon (E. S. R., 19, p. 249) is, as that author 

 suspected, not identical with P. pirina but that it has characters corresponding 

 precisely to those of C. tirolense. 



Tree crickets as carriers of Leptosphagria coniothyrium and other fungi, 

 W. O. Gloyer and B. B. Fui/roN (New York State Sta. Tech. Bui. 50 {1916), pp. 

 3-22, pis. 4). — The authors propose the name tree-cricket canker for a disease 



