iri2 EXPERIMENT STATION RECORD. 



botli Iriatmi'iits fcruatly reduced tin- itercentafi&of diseased onei^, thosje treated with 

 formalin l)eing aliii().st entirely free from the smut. The author believes that where 

 the convenienee and efticiency of tn-atment are coneerned the formalin is to be pre- 

 ferred above any of the other methods that have l)een suojgested for the prevention 

 of oat snmt. 



The bacterial disease of the potato, E. Marre {Prog. Agr. et Vil. {Ed. L'Est), 

 24 {190->), No. 17, ji/>. 5..'fJ-')2S). — A report ia given of investigations relative to the 

 bacterial disease of j)otatoes due to Banlltts solanincohi. In(]uiries were sent out to 

 a Dundjer of corresjiondents during ]902, and from the replies the author concludes 

 that the disease is influenced l)y atmospheric conditions, dry, hot weather aiding in 

 its si)read. The entrance of the organism to the ])lant is favored l)y the presence of 

 leaf-eating and stem-sucking insects. Most of the correspondents reported less dis- 

 ease on i>lants grown from whole tubers than from cut seed, and marked differences 

 in varietal resistance are noted.- Early or very late ])lanting gave the best results, as 

 such i)lant.s escaped the dry, hot weather which favored the sjiread of the disease. 

 However, early and late seeding and resistant varieties can not be absolutely depended 

 upon as means of preventing attacks of this disease. Treating the seed tubers with 

 formalin, corrosive sublimate, and copper sulphate solutions gave no jwsitive relief. 

 Sulplnir and ashes dusted over the tubers in the drills before covering was thought 

 by some to be of value, and this treatment will be given further trial. 



Potato blight (Cercospora concors), G. Lagekiieim and G. Wagner {K. LarnU. 

 Ahid. JIandl. och Tldslr., 42 {1903), Xo. 1, pp. 6-13, pis. J').— The history of the 

 api)earance of this potato disease is discussed at some length. It has been observed 

 during the last 10 years at a number of jilaces in Germany, Bohemia, and Austria. 

 On its appearance in Uphland, Sweden, in August, 1902, it was studied by the authors 

 as to its morphology and mode of development. Spraying with Bordeaux mixture 

 is suggested as the best method of combating the disease, besides burning all the 

 infected plants. — f. w. woll. 



Potato blight and. rot, W. T. ]\Iacoun {Ontario Agr. and Expt. Union Bpt. 1902, 

 pp. 4 --47, maps 2). — Popular descriptions are given of the early blight {Aliernaria 

 solani) and the late blight or rot {PInjtophthora infestans). Coojierative experiments 

 have been carried on in C)ntario for the prevention of these diseases, and the average 

 net results show profits ranging from !f;37.22to ?69.62 as a result of the increased pro- 

 duction due to the s[)raying. 



The internal action of copper sulphate in the resistance of potatoes to the 

 potato rot, E. Laurent {Compt. Rend. Acad. Sci. Paris, 135 {1902), No. 23,pp.l040- 

 1042). — On account of the great sensitiveness of the spores of Phytophthora infestans 

 to copper salts, the author has conducted a series of experiments to test the possibil- 

 ity of producing tubers that will not be susceptible to the attacks of this fungus. The 

 experiment was begun in 1901, varieties of potatoes exceptionally subject to disease 

 being grown in pots to the soil of which sulphate of copper was added at the rate of 1 

 part to 1,000 of soil. During that season the potato rot did not appear, so that the 

 results of the treatment could not be determined. It was continued, however, a 

 second year, and in August the disease appeared in considerable abundance. Tubers 

 were harvested and those of one variety were cut in two, their cut surfaces placed in 

 contact with the leaves of potato carrying the mildew. These were examined after 

 4 days, and those tubers which had V)een grown in the i)ot containing copper did not 

 show any infection, while the check ones were infected in a very decided manner. 



An analysis of the tubers grown in the pots showed that they contained 1 part of 

 copper to 20,000, while tubers grown without copper added to the soil did not show 

 the presence of any copper. An attempt was made to protect tubers against the 

 fungus by soaking them for 20 hours in from 2 to 5 per cent solutions of copper sul- 

 phate. After this treatment they were washed in water and exposed to leaves carry- 

 ing the Phytophthora. The parasite developed equally vigorously in all the speci- 



