DISEASES OF PLANTS, 751 



sound seed tubers under condilions favorable for the development of tlie causa- 

 tive orgauisms. 



After a discussion of the opinions of various investigators as to the cause of 

 this disease, the results are given of chemical analyses and mycological studies 

 of sound and diseased tubers. A mycological study of diseased tubers showed 

 the presence of a Fusarium in the flbrovascular bundles in many instances, 

 while in sound healthy tubers no mycelial threads were found. 



A bibliography is appended. 



The leaf -roll disease of the potato, R. Schandek (Ber. West Preuss. Bot. 

 Zool. Ver., 32 (1910), pp. 70-77). — In a paper read before the thirty-second 

 meeting of the West Prussian Botanical and Zoological Association held at 

 Mewe in 1909, the author gives the symptoms, means of dissemination, effects 

 on the yield, and methods attempted for the control of the leaf-roll dis'ease of 

 the potato. 



On the American g'ooseberry mildew and the black wart disease of the 

 potato. — II, Studies on the cause and propagation of this disease, K. Kock 

 {1911), -Yo. J, pp. 060-068}. — The authors give a brief history of the prevalence 

 and dissemination of these two diseases and the remedies used for their control. 



The American gooseberry mildew, E. S. Salmon (Jour. Southeast. Agr. Col. 

 IT'i/e, 1910, Xo. 19, pp. 331-335, pis. 2). — Previously noted from another source 

 (E. S. R.. 25, p. 248). 



New experiments on the control of the American gooseberry mildew, 

 Wagnee (Dciit. OUthuu 7A(j., 1911, No. 15-16, pp. 2.'i7, .^.),S').— Previously re- 

 ported from another source (E. S. R.. 24, p. 452). 



The relationship between the weather and grape mildew in Hungary, G. de 

 IsTVANFFi and F. Savoly (Rev. Tit., 35 (1911), Xo. 910, pp. 613-621).— A study 

 is reported of the progress of the mildew in 1910 and of the climatic conditions 

 of those regions in Hungary devoted to grape culture, including the winter 

 M-eather for 1908-9 and 1909-10, changes of temperature, rains, humidity of the 

 air, fogs, dews, cloudiness, and winds. 



It was found that the mildew increased in direct proportion to the amount of 

 preciptation ; that humidity of the air was the most important factor in the 

 appearance of the mildew, which was always preceded by a high degree of 

 humidity in the regions in question ; and that the weather during the winter 

 did not appreciably affect the mildew but that the distribution of the rains in 

 Hungary during April determined the locality of the first appearance of mildew, 

 while the later rains during May and June determined the direction and inten- 

 sity of its spread. 



Comparative experiments with certain sprays for controlling the downy 

 mildew (Peronospora viticola) of the grape, A. Bef.tschneider (Ztschr. 

 Landw. Vcrsuchsiv. Osterr., IJ, (1911), Xo. 5, pp. 806-813).— The effects noted 

 as to the control of the downy mildew are given for (1) 1 per cent Bordeaux 

 mixture, (2)1 and 2 per cent solutions of Tenax, (3) 1 and 2 per cent solutions 

 of Cucasa, (4) a 3 per cent solution of copper-soap mixture, (5) a 0.25 per cent 

 solution of " Crystalazurin " solution, and (6) 1 and 2 per cent salt solutions 

 made from certain rare earths. 



Apple rust, X. J. Giddings (Farm and Orchard, 1 (1911), No. 12, pp. 3-5, figs. 

 S). — Attention is called to the general prevalence and severity in West Virginia 

 during 1910 of this disease, which not only attacked the leaves, but severely 

 infected the fruit. It is suggested that moist, warm weather during March or 

 early April followed by cold weather during late April or May are important 

 weather conditions favoring the infection of apple trees by the cedar rust. It 

 would seem that the time of spraying rather than the kind of spraying is the 

 most important factor in controlling this disease. 



