552 EXPEEIMENT STATION EECOED. 



thereafter, every 2 weeks uutil the crop is harvested. Where the plants are 

 over 15 in. tall, they should be gone over twice at each spraying, the machine 

 moving in an opposite direction the second time. Demonstration plats sprayed 

 according to these directions were almost entirely free from blight, while all 

 checks which were not sprayed at all were practically ruined. 



Brief notes are also appended on other fungus diseases and insect pests of 

 celery. 



A bacterial disease of the Irish, potato, G. H. Pethybbidge and P. A. 

 MuKPHY {Nature [London], 85 (1010), No. 2148, p. 296). — In a paper read be- 

 fore the December meeting of the Royal Irish Academy at Dublin, the authors 

 describe a bacterial disease of the potato plant of frequent occurrence in Ire- 

 land, and give an account of the organism (for which the name Bacillus melOM- 

 ogenus is proposed) isolated from the diseased plants, and its successful inocu- 

 lation on healthy plants and tubers. 



The bacillus produces a decay of the living tissues of a variety of plants in 

 addition to the potato, and resembles in many respects other organisms causing 

 similar diseases in the Old and New Worlds. 



Some observations on the leaf-roll disease of the potato, T. Hedlund 

 (Tidskr. Landtmdn, 31 (1910), pp. 512-515, 532-5^1; abs. in Bot. Centbl., 11^ 

 (1910), No. 22, pp. 567, 568). — The author claims, from his observations and 

 study of the disease as it exists in southern Switzerland, that it can originate 

 without infection from leaf-roll diseased plants, and is caused primarily by a 

 checking of the respiration in the underground parts due to low temperature and 

 rainy weather in combination with a packed condition of the soil and the too 

 great depth at which the seed tubers have been planted. The diseased condi- 

 tion thus produced persists throughout the entire vegetative period of the 

 plants, resulting in a serious checking of tuber growth. 



It is also claimed that the disease can result from the use of seed tubers 

 from leaf-roll diseased plants, even when the weather conditions and other 

 external factors in the earlier stages of growth are entirely favorable. The 

 author believes that the leaf-roll disease is probably not infectious, but is only a 

 pathological adaptive mutation. 



For controlling the disease, a loose seed bed, sound seed tubers, not too deep 

 planting of the seed, and liming the soil are I'ecommended. 



A biochemical study of the leaf-roll disease of the potato. — I, The oxi- 

 dases of the tubers, G. Doby (Kis^rlet. Eoslem., 13 (1910), No. 5, pp. 595-615, 

 dgm. 1; Ztschr. Pflanzenkrank., 21 (1911), No. 1-2, pp. 10-17, dgm. 1).—A 

 study was made of the oxidases present in healthy plants and those attacked 

 by the leaf-roll disease, in which oxygenase, peroxidase, and tyrosinase were 

 found, but the quantities of each ferment present were not sufficient to distin- 

 guish between healthy and diseased tubers at the time of planting. 



A brief bibliography is appended. 



Contribution to the study of the leaf-roll disease of the potato, G. Kock 

 and K. Kornauth (Monatsh. Landw., 3 (1910), No. 12, pp. 365-369). — This is 

 a discussion of several recent articles on the leaf-roll disease of the potato, 

 especially with reference to its cause. 



The claims made by Bohutiusky-Krizevci (E. S. R., 23, p. 743) and Vauha 

 (E. S. R., 24, p. 1.54) as to the parasitic nature of this disease are held to be 

 unsupported by other investigators. 



Potato spraying experiments, 1910, D. Turner (Agr. Students^ Gaz., n. ser., 

 15 (1910), No. 2, pp. 38-.'i2). — The results of spraying experiments conducted in 

 the south of England with 14:9:100 Bordeaux mixtures for the control of the 

 late blight of the potato (Phytophthora infestans) , are reported. 



