246 EXPERIMENT STATION RECORD. 



In discussing the horse-radisli disease {Pseudonvon-as campestris), attention 

 is called to tlie fact ttiat only about one-fourth of the area formerly devoted to 

 this vegetable is now planted. This x*eduction is due, it is claimed, to the rav- 

 ages of this disease. Although it is usually supposed that P. campestris attacks 

 all cruciferous crops, yet growers were unanimous in their opinion that any 

 other crop, such as cabbages, Brussels sprouts, etc., could be successfully grown 

 on badly diseased land and invariably produce clean, healthy plants. Two forms 

 of the disease are common, one in which the interior of the horse-radish rots 

 throughout its whole length and the roots quickly become hollow, and the other 

 in which the interior remains sound but the outer iX)rtions rot. 



On diseases of sugar beets in 1910, O. Fallada (Osterr. TJngar. Ztschr. 

 Zuclccrinilns. u. Landiv., J/O (1911), No. 1, pp. S-^-JfO, figs. //). — The author gives 

 the distribution and relative intensity of the following diseases of sugar beets 

 in Austria-Hungary: Damping off, heart or dry rot, root rot (Rhizoctonia 

 violacea). crown gall, downy mildew, and leaf spot. 



In discussing the crown gall of the sugar beet the theories of several in- 

 vestigators as to the cause of the disease are given, together with a descrip- 

 tion of the structure of the tumor. 



Seed beds of sand as a means of combating the root rot (Thielavia basi- 

 cola), M. Benincasa (Bol. Tec. Coltiv. Tabacchi [Scafati], 10 (1911), No. 1, 

 pp. 3-22, figs. 7). — The author compares the results of experiments on using 

 ordinary garden loam, pure sand, and a volcanic cement pumice (pozzolana 

 grigia di Tivoli) as materials for seed beds for tobacco in regions affected 

 with the root rot organism (T. hasicola). Artificial fertilizers were used on 

 both the volcanic and sandy soil beds. 



The conclusion is drawn from these experiments that the usual vehicle of 

 infection is the soil commonly used in making the seed beds, and that heating 

 this soil to a temperature of 90° C. is not sufficient to entirely prevent the rot 

 in the seed beds. The seed beds of sand proved very efficient in controlling the 

 rot, while the volcanic soil gave the best results of all, both as to vigor and 

 growth of seedlings and in checking the rot. This was due apparently to the 

 physical condition of the soil, which permitted a robust development of both 

 the tops and roots of the tobacco plants by furnishing a warm and well aerated 

 seed bed. 



It is suggested that other similar substances, such as coal ashes, volcanic 

 scoria, and other volcanic rocks, naturally or artificially pulverized, should 

 act in the same manner as the volcanic material. As a means of controlling the 

 disease in the field the author advises the use of resistant plants like those 

 growTi in the volcanic seed beds or in sand, and crop rotation, preferably with 

 grain. 



[Fruit diseases] Oreg. Agr. Col. Bnl., 1. ser., 1911, No. J/S, pp. 52, 54, 

 pis. 2). — Attention is called to the prevalence of pear blight on both apples and 

 pears, and a warning is given that if not better controlled a serious epidemic 

 may occur. Apple scab is also reportal as becoming troublesome in La Grande 

 and Cove districts, while considerable so-called winter injury was f^und in the 

 spring of 1910 in the vicinity of La Grande and Union. 



Hypochnose of pomaceous fruits, F. L. Stevens and J. G. Hall (North 

 Carolina Sta. Rpt. 1909, pp. 16-85, figs. 8). — Previously noted from another 

 source (E. S. R., 21, p. 244). 



Scab, Monilia, and white leaf spot on different fruit trees, G. Kock 

 (Ztschr. Lanclw. Versuchsiv. Osterr., Iff (1911), No. 3, pp. 209-213). — On account 

 of the abnormal weather conditions during 1910 these diseases were very preva- 

 lent on diiferent kinds of orchard trees, and an opportunity was thereby 

 afforded of observing the susceptibility or resistance of many varieties. 



