48 
Pilzkrankkeiten der Pflanzen 
keit der Schädigung junger Pflanzen durch zu starke Insolation oft über¬ 
sehen worden zu sein. M. v. Piesenhausen (Bromberg). 
PRIOR, E.M., Contributions to aknowledge of “The Snap-BeeclT 
disease (Journ. Econom. Biol. 1913, 8, 249—263; 2 pl.). 
The disease for which the name “Snap-BeeclT' is suggested shows 
certain characteristic features. The trunks of attacked Beech-trees 
usually snap off at a more or less constant height of 15—20 feet from the 
ground. The fracture is approximately transverse across a portion of the 
trunk, but oblique across the remaining part, so that a large jagged 
splinter, about two feet long, remains. This is due to the fact that the 
wood on the former side is diseased, and consequently weak, for a con- 
siderable distance above and below the region of fracture, but is sound 
on the latter side. The base and upper parts of the trunk are sound. 
Fructifications of Polyporus adustus are always present in intimate 
connection with the diseased part of the tree; no other fungus is habi- 
tually present. The authoress concludes that the disease is probably 
caused by this fungus. Infection experiments by means of mycelium 
placed on the bare sapwood of living beech gave positive results. The 
fungus, in all probability enters through a wound, and advances very 
rapidly in the longitudinal direction, but slowly in the transverse; hence 
one longitudinal half of the diseased region is rotten while the other is 
still sound. The cortex and bark are reduced to a powdery white mass 
of little more than fungal liyphae. Of the wood elements, the vessels 
and the tracheids are the first to be disorganised and the medullary rays 
are the last. The spring-wood is disorganised sooner than the 
su mm er-wood. Dissolution of the walls of the wood elements proceeds 
centrifugally from the lumen of the cell. As soon as the lignified membrane 
is reduced to cellulose the latter is apparently dissolved away. The hyphae 
enter the constituents of the wood chiefly through the pits, but also 
pierce the walls. Many culture experiments were performed with mycelium 
from diseased wood, but no fructifications were obtained. The enzymes 
diastase, invertase, tyrosinase and emulsin were found to be 
present in the mycelium. J. Ramsbottom (London). 
BRICK, 15. Bericht über die Tätigkeit der Abteilung für 
Pflanzenschutz für die Zeit vom 1. Juli 1912 bis 30. Juni 
1913 (Jahrb. Hamburgischen Wiss. Anstalten 1912, 30, Hamburg 1913, 
S.-A. 27 pp.). 
Von den im Berichtsgebiete aufgetretenen Krankheiten verdient be¬ 
sonderer Erwähnung der im Kreise Pinneberg beobachtete Kartoffel - 
krebs, Chrysophlyctis endobiotica, der an den Sorten Magnum bonum, 
Kaiserkrone und Rosenkartoffel auftrat. In starkem Maße wurde 
auch der Maiblumenrost, Aexidium Convallariae , schädlich. Der 
Americanische Stachelbeermehltau hat im Frühjahr 1913 eine 
große Ausbreitung gewonnen und zeigte sich auch auf den bisher weniger 
von ihm befallenen Früchten. Gegen die verschiedentlich stark auftretende 
durch Plasmodiophora Brassicae verursachte Kohlhernie wurden Be¬ 
kämpfungsversuche angestellt mit dem aus Schlacken und Kalk bestehen¬ 
den STEiNERschen Mittel, mit einem vermutlich auch viel Schlacken ent¬ 
haltenden, in Hellbrook verwendeten Mülldünger, mit gebrannten Kalk, 
