NOTES AND ABSTRACTS. 16H 



Fusarium oxyspomm; (6) wet rot ; and (7) brown spot. These several 

 diseases are described and the various preventive measures recommended. 

 "Wet rot," found in land which is badly drained, is now considered to 

 be caused by bacteria, but whether one or more separate organisms are 

 primarily responsible has not yet been ascertained. "Brown spot" 

 affects the tubers, but up to the present no signs of any parasitic 

 organism has been discovered. — M. G. C. 



Potato Diseases. By A. Nelson (U.S.A. Exp. Stn. Wyoming, 

 Bull. 71 ; 11 figs. ; January 1907). — It is estimated that a loss of at 

 least $100,000 resulted from the partial failure of the potato crop in 

 Wyoming in 1906. The bulletin discusses the diseases due to Alternaria 

 solani (=Macrosporiu?n solani), early blight ; Phytophthora infestans, 

 causing late blight ; Corticium vagum solani (—Rhizoctonia), causing, 

 according to the virulence of the attack, a girdling of the stem, often 

 resulting in increased vigour or a wet rot of the stem ; and Oospora 

 scabies, causing potato scab. The first two are controlled by the appli- 

 cation of Bordeaux mixture at the proper season ; the last two by proper 

 rotation of crops and treatment of the seed potatoes with corrosive 

 sublimate or formalin. The latter is probably the better, and is carried 

 out as follows : The seed potatoes are soaked for two hours in a solution 

 of fifteen gallons of water and half-pint of formalin. The seed is dried 

 and planted as usual. — F. J. C. 



Potato Experiments. By E. A. Emerson (U.S.A. Exp. Stn. 

 Nebraska, Bull. 97 ; April 1907). — Seed potatoes were grown beneath a 

 mulch of litter and on cultivated ground in 1904, with the result that in 1905 

 and 1906 respectively, cultivated seed produced 384 lb. and 123 lb., while 

 mulched seed produced 563 lb. and 174 lb. from the same weights of 

 seed. Soft, sprouted tubers were found to give a less yield than firm 

 tubers, as is shown in the following table :— 



First test. Second test. Third test, 

 lb. lb. lb. 

 Soft, sprouted seed . . 129 225 212 

 Firm seed . . . 229 320 321 



giving an advance of 56 per cent, in favour of the firm seed. Treatment 

 with formalin was found to be excellent as a remedy against scab in 

 potatoes. The percentage of small tubers in a crop appears to depend 

 more upon the size of the seed pieces than upon the distance apart of 

 the plants, being greatest where large seed pieces were used. The yield 

 and value of the crop increased with the quantity of seed planted up 

 to a certain limit, while the yield and value of the crop increased with the 

 distance between the plants when a given quantity of seed was used, and 

 the yield depends much less upon the size of the pieces planted than 

 upon the quantity of seed per acre and the distance apart. Deep 

 planting up to 4 inches gave better results than shallow planting, 

 probably on account of the moisture and temperature varying less at that 

 depth.— F. J. C. 



Potato Leaf Blotch. By L. R. Jones and C. S. Pomeroy (U.S.A. 

 Exp. Stn. Vermont, 19th Rep. pp. 236-257). — A fungus, Cercospora 



