50 
Pilzkrankheiten der Pflanzen 
La temperature de 30—32° C empeche la germination des conidies 
et meine le developpement des cultures; le mininmm de temperature pour 
la germination des conidies est de -{-2° C. Le mycelium resiste bien au 
froid (— 15° C). 
La germination n’a pas lieu dans Teau alcalisee par carbonate de 
soude ä 5°/ 00 ou acidifiee par Packle tartarique ä 3°/ 00 . 
La germination est empeche par le biclorure de m er eure ä la 
concentration de 1:500000, par le nitrate d’argent (1:35000), par le 
clorure d’or (1:30000), parle sulfate de cuivre (1:20000). L’action 
preservative des polysulfures de calcium est temporaire; le soufre n 'em¬ 
peche pas la germination. 
Du mycelium des cultures peuvent etre isoles deux enzymes, une 
pectinase et une lipase, cette derniere attaque les substances cireuses 
et grasses de la cuticule. Le mycelium n elabore pas des toxines. 
La condition principale de receptivite des feuilles est determinee par 
la richesse en substances pectiques des couches de la membrane exterieure 
de l’epiderme et par leur minime cutinisation; le Cycloconium ne se deve- 
loppe pas sur les feuilles qui sont pres de tomber, M. Turconi (Pavia). 
STEWART, F. €., The persistence of the Potato late blight 
fungus in the soil (N. Y. [Geneva] Agr. Exp. Stat. Bull. 367, 
1913, 357—361). 
In these experiments soil containing blighted vines and decaying 
tubers was exposed to field conditions until Jan. 20. and was then brought 
into the greenhouse and planted with Potatoes. Attempts were repea- 
tedly made to inoculate the resulting plants by applying to their foliage an 
infusion of soil containing decaying potatoes and stems. These plants were 
placed in an inoculation chamber whose conditions of temperature and 
humidity were extremely favorable for infection. No infection appeared 
either on leaves or tubers, making it at least improbable that Phyto¬ 
phthora persists in the soil. F. A. Wolf (Auburn, Ala.). 
REDDICK, DONALD, Diseases of the Violet (Transact. Massachusetts 
Hort. Soc. 1913, 85—102; Pis. 2). 
A few brief prefatory paragraphs relative to the propagation of 
Yiolets, preparation of the soil, and cultivation are given since it renders 
clearer the discussion of the diseases. Among the fungi considered in tliis 
study are Thielavia basicola , Sclerotinia Libertiana , Alternaria Violae f 
Phyllosticta Violae and Botrytis vulgaris. Special consideration is given 
only to the first named organism, the various stages in its life cycle, the 
disease which it produces, and the methods of control. It seems evident 
that only perfectly healtliy cuttings sliould be used in propagating Violets, 
and that soil sliould be free from infectious material. Formaldehyde 
is effective in the soil sterilization wlien diluted to one pint in 12 x / 2 gallons, 
of water. Experiments on control by the use of lime, acid phosphate, 
wood ashes, and well rotted stable manure are in progress. 
F. A. Wolf (Auburn, Ala.). 
HERRMANN, Über den gegenwärtigen Stand der Kienzopffrage 
in Wissenschaft und Praxis (S.-A. aus 40. Vers. Preuß. Forstver. 
f. d. Provinzen Ost- und Westpreußen zu Braunsberg am 9./10. Juni 
