546 EXPERIMENT STATION KEf'OTtD. 



by the kind of soil in which the potatoes were gi»wn. as clay, sand, and ridi 

 loam wore alike subject to attack. Artificial inoculations on the toi)s of llu' 

 potato plants produced no infection. The warty growths on the i)otato tubers 

 are first white, then yellowish brown, and finally black in the last stages. The 

 diseased leaves are thickened, stunted, and covered with small warts. 



Keniedies suggested are the rotation of crops and the sorting of the potatoes, 

 cooking the diseased ones for cattle feed and storing the healthy ones in a 

 cool, dry place. Seed potatoes should be used that are known to be healthy 

 and should be planted in uninfected soil. Houses where potatoes are stored 

 and handled should be some distance from the fields. 



A discussion of the leaf roll disease of the potato, E, W. Schmidt {Dcut. 

 Landw. Presse, 36 {1909), No. 99, p. 1051). — Various experiments were con- 

 ducted by the author to determine the character of the leaf roll disease of the 

 potato. He finds that the fungus present in the diseased leaves will not grow 

 on healthy plants, and that all attempts to produce the disease by artificial 

 cultures are unsuccessful. The fungus found in the diseased plants is claimed 

 to be a saprophyte and, therefore, can not be the cause of the disease, which, 

 he concludes, is probably due to physiological causes rather than to the work of 

 any fungus parasite. 



Two epidemics of potato blight and rot, W. J. Morse (Maine Sta. Bui. 169, 

 pp. 165-18Jf, pis. 2). — This bulletin contains a discussion of epidemics of late 

 blight or rot {Phijtophthora infestans) of potatoes in Aroostook County, Me., 

 in 1907 and 1909. 



It is stated that much, if not all, of the disease comes originally from plant- 

 ing diseased seed tubers and that rain, dew, wind, insects, etc., are the chief 

 agencies in disseminating the disease. It is especially destructive in rainy or 

 cloudy weather, but can be controlled by thorough and persistent spraying with 

 5 : 5 : 50 Bordeaux mixture properly prepared and applied. The applications 

 should commence when the tops are 6 to 8 inches high and be repeated every 

 10 days, or every week if the weather is cloudy, and should be continued until 

 the frost kills the leaves. It was found that 50 gal., the amount usually 

 recommended per acre, was not sufficient to insure protection when the plants 

 were large and covered the ground. The spraying should not be omitted on 

 account of rainy weather, as this is the one time when spraying is most needed. 



It was also demonstrated on a large scale in 1909 that where potatoes are 

 blighting, it is unsafe to dig or store the crop for at least 10 days after the 

 tops are killed by frost, as the spores are showered down on the damp potatoes 

 and infect them, thus causing decay in storage. 



Bean anthracnose, H. von Diakonoff (Geisenh. Mitt. Ohst u. Gartenhaii, 2Ji 

 (1909), No. Ji, pp. 57-59, figs. 3). — An account is given of the bean anthracnose, 

 Colletotrichum lindemuthiantim, or Glceosporium lindcmiithianum, as the author 

 calls it, with suggestions for its control. The principal means recommended is 

 the selection of seed, all seeds showing any si)ots being rejected. 



Investigations of the relation between the character of the ground and 

 the appearance of the club root disease in Central Jutland, H, R. Christen- 

 SEN ET AL. (Tidsskr. Landbr. Planteavl, 16 (1909), No. 3, pp. ^3 0-1,7 6) .—The 

 authors conclude from investigations conducted during the summer of 1907 

 that where the club root disease is found and the soil appears to be acid and in 

 need of liming, the attack should be combated by heavy applications of marl or 

 lime. If the soil is not acid and the disease Is still present, the best remedy is 

 thorough drainage and improvement of the physical condition of the soil. 

 When a soil is acid and the disease has not yet appeared, applications of marl 

 and lime are to be recommended in order that the disease may not gain a foot- 

 hold should the soil become infected with the fungus. 



