280 



JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



Horne, B.Sc, F.G.S. {Centr. /. Bakt., Abt. II., Bd. 28, pp. 403-408; 

 plates). — A number of curious bodies were discovered in the apices of 

 certain rhizomes of Pteris aquilina similar to those seen in the potato 

 tuber by the author. These bodies and their development are described 

 and the author promises a further paper upon them. — F. J. G. 



Potato Soils, Fertilizers for. By Milton Whitney {U.S.A. Dep. 

 Agr., Bur. Soils, Bull. 65; May 1910).— Details are given of 1,769 

 tests of substances applied to all sorts of soils in twenty-three different 

 States.— i. P. 



Potato Spraying- Experiments in 1909. By F. C. Stewart, 

 G. T. French, S. M. McMurran, F. A. Sirine {U.S.A. Exp. 

 Stn., New York, Bull. 323; May 1910). — A series of experiments were 

 carried out by the above station and by a number of volunteer farmers 

 in different localities with the object of deciding as to whether or not in 

 the long run it is profitable to spray potatos. 



This bulletin also gives the results of 8 years' potato spraying experi- 

 ments beginning in 1903. 



The results show without exception an increase in yield from each 

 acre, which is often in direct proportion to the number of sprayings. 

 In one case the increase amounted to 191 bushels the acre for 3 spray- 

 ings and 233 bushels the acre for 5 sprayings. On the other hand the 

 expense of spraying in some cases was so great that it resulted in a loss, 

 whereas in others the gain amounted to $37.92 the acre. 



The gain or loss in potato spraying depends on so many factors such 

 as acreage of land cropped, current prices at the time of digging, 

 weather, locality, &c., that the individual results vary considerably, 

 but the average of all the experiments in 1909 taken together shows a 

 net gain of $9.55 the acre, and from 1903-1909 of $16.77 the acre. 



D. M. C. 



Potato, Wart Disease of. By W. A. Orton and Ethel C. Field 

 {U.S.A. Dep. Agr. Bur. PI. hid., Circ. 52; March 1910).— A new 

 and dangerous disease (which has not yet found its way into 

 the United States), due to a fungus belonging to the Olpidiaceae, the 

 lowest group of the Chytridiaceae. The fungus, Clirysophlyciis 

 e77dot'io/ica, causes dark warty excrescences on the tubers of the potato, 

 uses up every particle of food stored in the tuber, and reduces it to 

 a brownish soft mass, with an unpleasant putrefaction odour. The 

 starch grains are the last to be attacked, and remain white and uninjured 

 for some time m the affected cell. The parasitic plasmodium bores its 

 way through the cell walls, and at first stimulates active division in 

 the surrounding cells causing the characteristic galls or warts. 



In the summer the plasmodium rounds itself off to form a 

 zoosporangium inside the cell. Later the zoosporangium breaks up into 

 numerous zoospores, which escape into the soil and infect fresh plants. 



The resting zoosporangia are very numerous in the diseased tubers, 



