1919] DISEASES OF PLANTS. 747 



had been found in three counties in Illinois and three in Indiana. The flag 

 smut, which is caused by Urocystis tritivi, is reported from Madison County, 

 III. Attention is called to these diseases in order that the occurrence might 

 be reported and their possible spread prevented. Suggestions are given for 

 their control, which are based largely on proper rotations, and for the flag 

 snmt the treatment of seed before planting. 



[Barberry and wheat rust], E. M. Freeman {Minn. Hort., 46 {1918), No. 4, 

 pp. 168-170, figs. 2). — This is a brief exposition of contrasts between the com- 

 mon barberry {Bcrberis vulgaris) as a bearer of wheat rust and the Japanese 

 barberry {B. thunbergii), which is harmless in this respect, with a discussion 

 of the success attending the eradication of the former species, which is a 

 lK).st of the black stem rust. 



Ear cockles in wheat, W. Somerville {Jour. Bd. Agr. [London'\, 25 {1918), 

 No. 7, pp. 850-853, fig. 1). — In experiments carried out with the varieties Nursery 

 and Dutch White Wheat, it was found that steeping for 24 hours in 1 per 

 cent copper sulphate solution reduced nematode infection and gave a consider- 

 ably increased percentage of sound grains. 



Smut diseases of barley and oats, W. B. and S. P. Mercek {Jour. Bd. Agr. 

 [Londo7i], 25 {1919), No. 12, pp. 1486-1493, pis. 2).— Tliis paper is comple- 

 mentary to the one previously noted (E. S. R., 37, p. 839), and is intended to 

 complete the account of smuts affecting the ordinaiy food cereals in England. 

 The series concludes with a synoptic survey in tabular form of such diseases, 

 their diagnostic symptoms, and appropriate treatments. 



Segregation of susceptibility to parasitism in maize, D. F. Jones {Amer. 

 Jour. Bot., 5 {1918), No. 6, pp. 205-300).— The inbred strains of maize reported 

 upon by East and Hayes (E. S. E., 27, p. 428), continually selfed up to the 

 time of this report, are said to show striking dilferences in the number of 

 plants affected by the smut fungus {Ustilago ;:cce) and an unidentified leaf 

 blight organism. This organism in 1914 injured seriously a few inbred strains 

 of flint maize and in 1916 affected the same strains in the same way, other 

 selfed strains from different varieties in adjoining rows being almost entirely 

 free from this organism. First generation hybrids of these susceptible strains 

 with resistant types grown in the same field were only slightly affected. No 

 plants showed in 1917 any injury from the leaf-blight fungus, but several 

 strains were seriously attacked by smut. The data are tabulated for studies 

 carried out on the susceptibility of strains differing as to genetic history. 



The facts here recorded are considered as additional support to the hypo- 

 thesis previously advanced by the author (E. S. R., 3S, p. 307; 40, p. 220) 

 that the increase in development commonly shown by hybrids is due to con- 

 junctive action of a large number of favorable, dominant growth factors 

 contributed by both parents. Vigor is thought to be, in this case, only a minor 

 factor causing variation. The evidence from these inbred strains of maize 

 and their first and second generation hybrids is thought to show that suscepti- 

 bility is governed by factors capable of being segregated into some lines and 

 not into others, the modification of the expression of parasitism by the vigor 

 of the plants being a minor consideration. 



A bacterial root rot of field corn, H. R. Rosen {Arkansas Sta. Bui. 162 

 {1919), pp. 3-7, pU. 4)- — A description is given of a disease of field corn which 

 was observed by the author on a farm in this State. The characteristic feature 

 of the disease is said to be shown v»'heu the stalks are cut through their 

 long axis. The lower node or joints to which the roots are attached showed 

 a purplish-brown discoloration on the cut surface, while the internodes pre- 

 served their normal white color. The extreme base of the stalk was similarly 



