1917] DISEASES OP PLANTS. 249 



unsuitable soil and animal and plant parasites, including nematodes (Heterodera 

 radicicola) and an unnamed cobweb fungus on the leaves. 



Potato diseases in the Dutch East Indies, Johanna Westerdijk (Teys- 

 mannia, 27 (191G), No. 1-2, pp. 1-15, pi. 1). — This is a discussion of potato 

 varieties, culture, and diseases with related protective measures. The diseases 

 include Pfiytophthora infestans, Macrosporium solani, leaf roll, a leaf rust, 

 and a root fungus. 



Experiments for control of potato canker, E. Werth (Mitt. K. Biol. Anst. 

 Land n. Forstw., No. 16 (1916), pp. 9, 10). — Experiments with sulphur on the 

 potato varieties Wohltmann, Silesia, and Industry gave a lowering of canker 

 infection amounting to less than one-third, accompanied by a decrease of more 

 than three-fourths in yield. Tests for resistance showed less than 10 per cent 

 susceptibility in Kalserkrone, Richter Imperator, Fiirstenkrone, Gertrud, 

 Schnellert, and Paulsen July. 



Potato leaf roll in France, E. Foex (Bui. Soc. Path. Veg. France, 1 (1914), 

 No. 1, pp. 4^-48). — Potato leaf roll is said to attack severely several varieties 

 of potato in the canton of Orchies in northern France. 



Potato leaf roll, O. Appel and O. Schlumberger {Mitt. K. Biol. Aiist. Land 

 u. For Stic, No. 15 (1914), PP- 8-11, fig. 1). — The authors continue to report on 

 the study of potato leaf roll previously noted (E. S. R., 27, p. 247; 28, p. 52; 

 31, p. 52; 34, p. 443). The results obtained by planting the diseased stock from 

 different sources on various soils were not consistent throughout. Improve- 

 ment was noted in some cases, while in others the leaf roll appeared later in 

 the season. 



Chlorosis of beets, G. Aenaud (Bui. Soc. Path. Veg. France, 2 (1915), No. 2, 

 pp. 123, 124). — Describing the foliar discoloration in sugar beets previously 

 noted by Berthault (E. S. R., 35, p. 350) and by Mi6ge (E. S, R., 36, p. 543), the 

 author states that the trouble was somewhat general in the north of France 

 during 1915. It is thought that the phenomenon is related causally to the 

 prevalence of Cercospora beticola, Vromyces betCB, Phoma tabiflca, and leaf 

 aphids, in connection with lack of water, cultivation, and fertilizers, and with 

 late seeding. 



Crown gall of sug'ar beets, Peters (Mitt. K. Biol. Anst. Land u. Forstw., 

 No. 16 (1916), pp. 12, 13, fig. 1).—In 1912, beets penetrated to a depth of 2 to 

 3 cm. with a needle which had been dipped in cultures of Bacillus tumefaciens 

 showed partial, or doubtful, results. On repeating the tests the next year, how- 

 ever, and using also shallower penetration (0.5 to 1 cm.), a high percentage 

 of the plants so treated developed crown gall, while the controls were free from 

 enlargements. 



Sweet potato diseases, J. A. McClintock (Virginia Truck Sta. Bui. 22 

 (1911), pp. 455-486, figs. 14). — Popular accounts are given of diseases of the 

 sweet potato, with suggestions for their control. 



The diseases are classified according to the part of the plant involved as those 

 of the above-ground parts, those of the roots, and those of both vines and roots. 

 For the control of many of the diseases, and especially of the more destructive 

 of those affecting both vine and roots, the author recommends careful selection 

 of seed tubers, their treatment with corrosive sublimate solution, and planting 

 in seed beds in which clean sand has been substituted for soil. The cuttings 

 should afterwards be planted in soil that is known to be not infected or where 

 sweet potatoes have not been planted for several years. 



Sclerotium disease of tobacco, Johanna Westerdijk (Meded. Deli-Proef- 

 stat. Medan, 10 (1916), No. 2, pp. 30-40, pis. 2).— A study of a disease of young 

 tobacco, carried on at the Dell Station, is said to indicate that the trouble is 



