886 EXPERIMENT STATION RECORD. 



Africa, and the report is given as a contribution to the pathology and biology of 

 tropical economic plants. 



[nsect attacks and fungus and bacterial diseases are described, several of them 

 seeming to be closely related. The effect of plant Lice ( Aphis sacchari and A. <i<hi*t<i ) 

 is described, and the indirect effects they cause as shown by fungus and bacterial 

 diseases are pointed out. The attack of cicadas is noted and a description given of 

 the various smuts that have been observed as attacking sorghum in East Africa. 

 Among the species noted are Ustilago sorghi, U. cruenta, U. reUiana, fflBiyposporium 

 filiferum, and T. volkermi. 



An account is given of experiments with U. cruenta, showing the influence of vari- 

 ous factors on the spread of this smut. Notes are given on a large number of fungi 

 known to occur on sorghum, and in an appendix the author describes the work of 

 stalk borers and also a number of wound diseases which seriously affect the plant. 



Investigations on some seedling diseases of beets, L. IIiltnek and L. Peters 

 ( Arb. K. Gesundheitsamte, Biol. AbL, 4 (1904), No. 3, pp. 207-253). — Some of the dis- 

 eases to which beet seed lings are subject are described, special attention being paid 

 to those caused by Phoma betse. The influence of soils on the diseases is discussed 

 at length, and the possibility of conveying disease through seed balls is shown. 



The results of experiments in treating beet seed with a number of fungicides and 

 fertilizers are given. Among those tested were oxalic acid, malic acid, potassium 

 oxalate, monopotassium phosphate, ammonium carbonate, caustic potash, corrosive 

 sublimate, phosphate and carbonates of lime. The highest percentage of germination 

 and lowest of disease was obtained in the pot experiments where dry carbonate of 

 lime was sprinkled over seed planted in moist sand. Seed so treated were practically 

 free from disease. Following the results of this experiment the lowest percentage 

 of affected seedlings was obtained where phosphate of lime was used in a similar 

 manner. 



Investigations on the zonal scab of beets, F. Kruoer (Arb. K. Gesundheitsamte, 

 Biol. Abt., 4 (1904), No. 3, pp. 254-318, pi. l,figs. ft).— Attention is called to the scab 

 of beets, and its possible relation to the potato scab is discussed. The results of the 

 author's investigations which were made on this form of disease on the beet are 

 given at length. 



The scab of the beet seems to occupy a definite part of the root, often completely 

 girdling it, hence the name zonal scab. As in the case of the potato scab, the disease 

 is attributed to a fungus, but the author believes it is not identical with Oospora 

 scabies of the potato. Cultures made with the organisms showed constant differences, 

 and the author has separated 6 species of Oospora, 5 of winch are described as new. 



The sugar content of the diseased beet was found to be lowered almost in direct 

 proportion to the amount of scab observed upon the roots. Numerous methods for 

 combating the disease are reported upon. According to a quoted authority, drainage 

 and cultivation and, under certain conditions, the use of lime will give some relief 

 from the disease. This must be carried on in connection with rather long rotation 

 of crops. 



A form of scab due to the attacks of small worms is also described, and a bibliog- 

 raphy of the subject is appended. 



Tobacco diseases, A. D. Selby (Ohio Sta. Bui. 156, pp. 87-107, pis. 5, figs. 3). — 

 The recent establishment of a station to test some of the tobacco problems in Ohio 

 has led to a consideration of some of the tobacco diseases. The author presents a 

 preliminary report of experimental studies on the mosaic disease, root rot, seed bed 

 rot, broom rape, and curing-house troubles in Ohio. 



The mosaic disease, which is one of wide distribution, is described at considerable 

 length and the various theories concerning its cause are briefly reviewed. The dis- 

 ease is quite prevalent in southwestern Ohio tobacco fields, and some preliminary 



