1 62 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



The relations of Parasite to Host and Environment. — One cannot fully under- 

 stand the diseases of the potato except as he understands them in relation not 

 only to the normal physiology and morphology of the plant, but in relation to its 

 history and its variations under culture. The pathologist of the past has been 

 a mycologist and a bacteriologist ; the pathologist of the future must be a 

 physiologist ; for what is pathology but abnormal physiology ? 



The Problems of Disease Control. — Spraying and seed treatment are only a 

 part of sanitation. Full data as to the life-histories and dissemination of causal 

 organisms are more important fundamentals. There is also the question of 

 disease resistance and immunity, which is of great importance. 



In conclusion, the demand upon a phytopathologist is equally urgent for four 

 types of service : (a) College teaching ; (b) extension teaching ; (c) inspection ; 

 (d) research. These lines must be realized if the best results are to be secured. 



A. B. 



Pleione pogonioides (Bot. Mag. tab. 8588). — China. Nat. Ord. Orchidaceae, 

 tribe Epideyidreae. Herb, terrestrial, 3-4 inches high. Leaves 2-6| inches long. 

 Flower terminal, showy, rosy red, 2 inches long. — G. H. 



Potash Salts, Alunite and Kelp as. By J. J. Skinner and A. M. Jackson 

 (U.S.A. Exp. Stn., Dep. Agr., Bur. Soils, Cir. 76; April 1913). — Alunite, de- 

 scribed as a double sulphate of potash and aluminium, when ignited, gave 

 rather better results than potassium sulphate. On the other hand, raw ground 

 alunite was not so effective as the latter. 



Kelp, in comparison with potassium chloride, gave equal results in crop, 

 with better growth. The authors therefore recommend alunite and kelp as 

 satisfactory substitutes for the sulphate and chloride of potassium salts. — C. P. C. 



Potato Blight In India. By J. F. Dastur {Mem. Dep. Agr. India, Bot. 

 Ser. vii. 3, Apr. 1915 ; plate). — Potato blight (which is also called by the author 

 " leaf curl ") due to Phytophthora infest an s broke out in the plains in 1912-13. 

 It is thought to have been introduced by " seed " from the hills obtained late 

 in the season. Tubers from diseased plants kept in sand produced healthy crops 

 in the succeeding year, whether in fresh or in the old soil. The fungus in pure 

 culture died out in the hot season. The author considered the high temperature 

 to which the tubers were exposed during the hot season killed the fungus, and 

 believes there is no fear of its spread if tubers for seed are allowed to pass part of 

 the summer in the plains. — F. J. C. 



Potato Scab. By G. P. Darnell-Smith {Agr. Gaz. N.S.W. vol. xxv. 

 pp. 869-872). — The term Potato Scab is applied to a roughening of the skin of 

 the potato, which may be due to widely different causes : (1) abrasion produced 

 by wire-worms, millipedes, cut worms or eelworms ; (2) the action of fungi. 

 Oospora scabies covers the surface of the tuber with mycelium. Rhizoctonia 

 Solani causes Black Speck Scab ; the potato is covered with black specks. The 

 threads of the fungus may penetrate the tuber and cause it to rot. Potato Dry 

 Scab is due to Spondylocladium atrovirens. The tuber is covered with white or 

 violet blotches, sprinkled with black spots. Spongospora subterranea causes 

 corky or powdery scab. Black Wart disease is due to Synchytrium endobioticum. 

 Some protection against 3cab is secured by immersing the seed potato in dilute 

 formalin (1 : 500) for two hours. — S. E. W. 



Potato Wart Disease, Experiments in Preventing. Anon. (Jour. Bd. Agr. xxi. 

 pp. 1126-1128; March 1915). — Treatment with commercial formaldehyde and 

 water (1 to 100), formalin (1 to 100), mercuric chloride ( - i per cent.), sulphate 

 of potash (10 cwt. to acre), kainit, and salt, in various localities in England, failed 

 entirely to check the wart disease. ' Epicure,' ' Up-to-date,' ' King Edward VII.,' 

 ' Duke of York ' were the varieties grown. ' Iron Duke,' a selected form of 

 ' President,' proved very susceptible to attack. — F. J. C. 



Potatos, Cheap Compound v. Home-mixed Manures for. By R. N. 



Dowling (Lindsey C.C., Bull. 3, 1914-15). — A comparison was made between 

 the values of home-mixed manures containing (1) sulphate of ammonia 1 cwt., 

 sulphate of potash 1 cwt., superphosphate 4 cwt. (cost £11 35.) ; (2) sulphate 

 of ammonia 1 cwt., superphosphate 4 cwt. (cost £1 3s.) ; (3) nitrate of soda 

 i£ cwt., sulphate of potash 1 cwt., superphosphate 4 cwt. (cost £1 15s.), and 

 (4) three compounded manures at the cost relative to the area covered of 

 £1 19s., £1 igs. 6d., and £2 os. 6d. The three plots dressed with the home- 



