DISEASES OF PLANTS. 343 



Leaf roll of potato, G. Kock {Wiener Landw. Ztg., 64 {1914), No. 41, pp. 382, 

 383, fig. 1). — The author shows the progress of the organism associated with 

 leaf roll of potato in the vascular system of the stems attacked. It gains en- 

 trance probably at some superficial wound and spreads finally to or through 

 the vascular system of the tubers on such shoots, other shoots from the same 

 parent tuber in some cases remaining free from the disease. A secondary in- 

 fection may or may not spread from infected tMbers to plants produced there- 

 from. Tubers borne by infected shoots may be simply weakened without being 

 actually reached by the fungus. 



Spraying potatoes for the prevention of potato disease or late blight, T. 

 MiLBURN and R. C. Gaut {County Council Lancaster, Ed. Com., Agr. Dept., 

 Farmers' Bui. 27 {1914), pp. 25). — Giving methods and results of experiments 

 during eight years looking to protection of potatoes against late blight {Phy- 

 tophthora infestans) by the employment of various liquid and dry fungicides, 

 the authors state that in most cases spraying reduced the loss, especially when 

 the outbreak occurred late in the summer, and that the crops from sprayed 

 plats also kept better than others. On the whole, however, spraying is not to 

 be unreservedly recommended, since especially on stiff, retentive soils and 

 near manufacturing towns the fungicides in either wet or dry form may spot 

 and dwarf the foliage and decrease the crop. 



Sprayed crops when not greatly injured usually retain their leaves longer 

 than unsprayed in diseased areas, and thereby yield a larger total crop with a 

 smaller percentage of brown tubers; but when the tops are injured, crops may 

 be considerably decreased. No efficient fungicide has as yet been found to be 

 without at least occasional injury to the potato foliage or crop, but if the dis- 

 ease appears late the injury is relatively small and is overbalanced by the 

 benefit. Spraying twice in the season is regarded as causing too much risk 

 unless the disease appears early and threatens to progress rapidly. On the 

 whole, the single late spraying as soon as the disease appears on the most sus- 

 ceptible area has given the best results, but this point is considered to require 

 further investigation. 



The use of Burgundy mixture for Irish blight {Agr. Qaz. N. S. Wales, 25 

 {1914), No. 1, pp. 48-50). — Though it is said that up to the present time the 

 most successful method of attacking late blight of potatoes in New South 

 Wales has been the use of Bordeaux mixture, it is claimed that recent expe- 

 rience in parts of Ireland has indicated a degree of superiority for Burgundy 

 mixture for this purpose. Directions are outlined for the preparation and use 

 of the latter fungicide, with the advantages claimed therefor. 



Phytophthora arecse causing a rot of potato tubers, J. Rosenbaum {Phyto- 

 pathology, 4 {1914), No. 5, p. 387). — As a result of cross-inoculation work with 

 several species of Phytophthora, the author claims to have found that P. arecce 

 is able to cause a rot of the potato tuber. The rot caused resembles in every 

 respect the pink rot previously described as caused by P. erythroseptiea (E. S. 

 R., 31, p. 543). Comparisons of the two species lead the author to believe that 

 they are at least closely related, if not identical. 



Fungus enemies of the sweet potato in Indiana, C A. Ludwig {Proc. Ind. 

 Acad. Sci., 1912, pp. 103, 104). — According to the author stored sweet potatoes 

 in Indiana have been found infected with Rhizopus spp., Nectria ipomoew, 

 Penicillium spp., Diaporthe hatatatis, Sphwronema fim,briatum, and Fusarium 

 spp. 



Blossom-end rot of tomatoes, C. Brooks {Phytopathology, 4 {1914), No. 5, 

 pp. 345-374, pis. 3, figs. 5). — The results of an extended study on the blossom- 

 end or point rot of tomatoes, a disease of general occurrence in tlie United 



