DISEASES OF PLANTS. 979 



efficiency of this treatment, ami the amount of fungicide mentioned ahove is sufh- 

 eient for the treatment of from 40 to 50 Ini. of (.at8. It is state<l that through the 

 intervention of the station at least 10,000 Wisconsin fanners treated their seed oats 

 with this solution during the i)ast year. 



The same method of treatment is reconuiiended for the prevention of juitato scah. 

 In this case the ])otatoes should he completely submerged in the lifjuid and left for 

 2 hours, or if the jiotatoes are very scabby for 2J hours. 



Some potato diseases {Jour. Bd. Agr. [Londoii], 9 {1903), No. 3, pp. 307-311, 

 pix. 3). — Descriptive notes are given on the black seal), bacterial disease, and sclero- 

 tium disease of potatoes. The black scab, which is said to be due to CEdomyces 

 Ii'proides, has been previously described as occurring on beets (E. S. R., 14, p. 57). 

 During the autumn of 1901 specimens of diseased potatoes were received from the 

 neiglil)orhood of Liverpool, and during the season of 1902 similarly diseased tubers 

 were observed from a mim))er of localities in England. On the {)otato the fungus 

 produces a continuous rough, black, scab-like, thick crust, which usually commences 

 at one or several distinct points and finally covers the entire surface of the tuber. 

 The central portion of the diseased tubers remains sound, the fungus never spread- 

 ing beyond the surface layer. If left lying on the ground the entire tuber becomes 

 dry, eventually crumbling to pieces. Diseased tubers should be collected and burned 

 or deeply buried, and land which has produced a diseased crop shoidd receive a 

 liberal dressing of lime. 



The bacterial disease of ])otatoes due to Barlllu.^ t^oldiiaccdrum has ))een reported 

 from a number of localities, and the author recommends the spraying of the potatoes 

 for the destruction of the leaf-eating insects as a preventive measure. If potatoes 

 are dug as soon as the disease is indicated by the wilting of the leaves, a considerable 

 portion of the crop may be saved by storing the tubers in a cool, dry place. 



The sclerotium disease of potatoes is characterized by the growth of the fungus on 

 the base of the stems just above the ground line. The tubers are never directly 

 attacked by the fungus, but their growth is either cliecked or entirely arrested by 

 the destruction of the above-ground parts of the plant. The fungus first appears at 

 the l)ase of the stem as a white, fluffy mass surrounding the stem, and after a time 

 tliis mold collapses and bears numerous black bodies about the size of a grain of 

 wheat. During the period of this development the potato stem and leaves have 

 become wilted and both perish soon after. The only certain method of combating 

 this disease is the collection and burning of all diseased j)lants. In addition to the 

 potato, the fungus, which is Sclcroiinki sclerolionnu, attacks a number of other garden 

 and field plants. 



A new potato disease, M. C Potter {Jour. lid. Agr. {^London'], 9 {1902), No. 3, 

 pp. 3;i0-3:^S, pi. 1). — During the autumn of 1900 the author's attention was turned 

 to potatoes presenting the irregular, tumor-like swellings (!haracteristi(; of the club 

 root of turnips. These excrescences consist of masses of thin-walled parenchymatous 

 cells rich in stan-h. Spores are produced in great abundance, but all attemj)ts to 

 secure their germination failed. The author was able, however, to infect sound 

 potatoes and reproduce the disease by inoculating the soil with the spores. Pot 

 experiments are reported upon in which potatoes were grown and the disease pro- 

 duced, the pots being allowed to remain with the soil undisturbed until the next 

 spring. A second planting showed that the parasite could be carried over winter by 

 means of spores in the soil and infest succeeding crops. The author believes that 

 the attack of the disease begins at or near the eyes of the potato, the parasite easily 

 gaining entrance through the young and tender structures existing at those points. 

 This disease is believed to be identical with that formerly described by Schilberszky 

 from Hungary, which is attril)uted by him to tlie fungus Chry><oi>hliirlix nidobiotica. 

 At present the author has observed the disease from but a single locality, but on 



