300 
Pilzkrankheiten der Pflanzen 
GROSSENBACHEß, J. G., Crown-rot of fruit trees: Field studies 
(New York Agric. Exp. Sta. Tech. Bul. 23, 59 pp., 4 pl., Sept. 1912). 
Field studies in New York state and around Madison, Wisconsin 
from 1909 to 1912 indicate a considerable amount of injury to fruit and 
shade trees resulting in the loosening of the bark near or below the 
surface of the ground, followed by disintegration of the most seriously 
affected bark, and eventually the entrance of heart-rotting fungi. This 
condition is termed crown-rot. Likewise, similarly cankered areas may arise 
at crotches or at points most subject to strong wind strain. 
The author thinks the trouble due to untoward growth and climatic 
conditions, such as, 1, an unusually large diameter growth during the 
vegetative season or a premature cessation of bark differentation due to 
adverse environmental conditions, both of which give rise to high bark 
tension; 2, low temperatures which likewise increase bark tension; 3, ex¬ 
posure to wind, resulting in great strain and excessive evaporation. 
The death of the loosened patches of bark appears to be due to 
isolation and drying out, the underlying wood frequently becoming stained 
on the resumption of vegetative activities in the spring and finally 
decaying. 
Different varieties of Apples showed a marked difference in sus¬ 
ceptibility. In wind-exposed regions the loss to fruit growers is heavy. 
Possible remedies for the trouble consist in providing windbreaks and 
more careful pruning, for it was observed that high-headed or severely- 
pruned trees were more susceptible. Inspection of trees in the spring 
for loosened bark or clefts should be made, the loose bark removed and 
the exposed surfaces treated with grafting wax or tar paint. 
The author reports the successful production of bark injury by 
packing a mixture of ice and calcium chloride around the base of Apple 
trees 10 to 12 years old. Circumference measurments on apple tree 
trunks between Nov. 8, 1911 and April 6, 1912 indicate a maximum 
chrinkage at —28,3° C between 1,8 and 3,1%. Similar measurments 
on frost-cracked linden and catalpas trees at Madison, Wise, showed clefts 
from 1,3 to 2 cm wide and 1 to 4 meters long; actual contraction in 
circumference, exclusive of the clefts, varied from 2,4 to 5,6 % between 
— 28,3° C and 21° C. C. J. Humphrey (Madison, Wise.). 
LAUBERT, R., Altes und Neues über die wichtigsten Krankheiten 
der Rosen und ihre Bekämpfung (Handelsbl. f. Deutsch. Garten¬ 
bau 1913, 28, 280—282, 296—298). 
Eine allgemeinverständlich gehaltene Beschreibung folgender Krank¬ 
heiten: Rosen mehl tau ( Sphaerotheca pannosa), Rosen rost (. Phrag - 
midium subcorticium ), Stern rußtau der Rosen (. Actinonema Rosae), 
Falscher Rosenmehltau (. Peronospora sparsa ) und der Brandflecken¬ 
krankheit der Rosen ( Coniothyrium Wernsdorffiaë) , welch letztere 
auch nach des Verf. Ansicht nicht mit C. Fuckelii identisch ist. Bei 
jeder Krankheit werden außer einer genauen Beschreibung des Krank¬ 
heitsbildes und des Krankheitserregers die Bekämpfungsmaßregeln ein¬ 
gehend erörtert. Zum Schlüsse gibt Verf. noch eine chronologische Zu¬ 
sammenstellung aller im Laufe des Jahres zum Schutze der Rosen not¬ 
wendig werdenden Maßnahmen. W. Fischer (Bromberg). 
