338 Pflanzenkrankheiten. 



on apple which are three years old, and they look as natural a& 

 the day they were cut from the fruit. The casts should be handled 

 with moderate care and ought not to be exposed to direct sunlight, 

 Perhaps this method can also be used by the horticulturist in 

 building up a collection of normal type specimens; it could in some 

 cases effectively beused on vegetables, which have a fairly tough skin. 



M. J. Sirks (Haarlem). 



Mercer, W. H., Investigations of Timothy rust in North 

 Dakota during 1913. (Phytopathology. IV. p. 20—22. 1914.) 



During the year 1912 the writer has accumulated inspectional 

 observations and laboratory, microscopic, greenhouse and field data 

 about the occurrence of Timothy rust, Puccinia phlei-pratensis Eriks, 

 and Henn,, which has been prevalent and very destructive in this 

 season in various parts of North-Dakota. The living-conditions 

 of the tungus in North-Dakota are very different from those in 

 Sweden, where Erikson and Henning found a period of about 

 one month only, when there were no new pustules forming, while 

 in North-Dakota the fungus is not very active until late in Juiy 

 and uredospores are very difficult to find after the first hard freeze. 

 Bundles of rusty timothy straw, bearing both uredo- and teleuto- 

 spores, were secured and placed in large tin cylinders having both 

 ends covered with wire netting only. These cylinders were exposed 

 to the weather all winter, in such manner that the straw did not 

 become damp. Most attempts to bring these uredo- and teleutospores 

 into germinating failed; only teleutospores germinated feebly in 

 March. Teleutospores from both wheat and timothystraw were sown 

 on barberry leaves under bell jars in the greenhouse. Infection was 

 readily secured from the wheat but none from the timothy rust. 

 The data, obtained by the writer, tend to show that there is no 

 relation between grain and timothy rust and probably none between 

 the latter and rusts of other grasses mentioned in the paper. It also 

 points out a considerable danger from this new menace. Remedies 

 lie naturally along the lines of breeding and selection for resistance, 

 and also in a more thorough study of the life history of the fungus 

 with a view to discovering a vulnerable point of attack b}'^ other 

 means, possibly comparable to treatment of smut in wheat. 



M. J. Sirks (Haarlem). 



Nalepa, A., Neue Gallmilben. 31. Fortsetzung. (Anz. ksl. 

 Ak. Wiss. Wien, math.-nat. Klasse. XXVII. 4 pp. 1914.) 



Folgende neue Gallen werden nebst den Erregern beschrieben: 



Erineum auf Carphms Betuhis, erzeugt von Eriophyes pulchella 

 (in Gesellschaft anderer bereits bekannter Arten), 



Blattdeformation auf Rosa spinosisshna , erzeugt von Eriophyes 

 rhodiies, 



Deformation des Fruchtknotens von Arctostaphylus nva-iirsi, 

 erzeugt von Eriophyes Jaapi. 



Die ersten beiden Gallen stammen aus der Wiener Umgebung, 

 die letzte aus Hannover. Matouschek (Wien). 



Orton, W. A., The biological basis of international phy- 

 topathology. (Phytopathology. IV. p. 11—19. 1914.) 



The paper, published in February 1914, is written in view of 



