Pilzkrankheiten der Pflanzen 
91 
blight, amounting in the first case to almost complete immunity. “Northern 
Invincible” also showed marked resistence. Two possibilities with regard 
to where the capacity of resistence lies present themselves. It may either 
lie in the exterme covering tissues of the plant or the resisting power 
may be something internal in the particular variety. Experiments were 
conducted by inoculating portions of different varieties. The several 
varieties behaved differently with regard to their reaction to the fungus, 
the behaviour of any one variety being constant throughout the various 
series. The variety “Shamrock” was least affected. The experiments 
suggest that resistance is due to something internal in the tissues. 
In the case of Sclerotinia sclerotiorum experiments showed quite 
strikingly that the number of plants attacked by the disease diminishes 
very steadily with increasing lateness of planting. The greatest yield was 
given by planting in the middle of May. In experiments for finding some 
means of freeing land contaminated with Spongospora subterranea “the 
best result was obtained with sulphur, where not only was the amount 
of disease reduced to less than one-half of that in the untreated plots, 
but the total yield was higher than in any other case”. Ten varieties of 
potatoes have been tested during the past three years with a view to 
ascertaining whether they differ in their respective susceptibilities to the 
attacks of the disease. There is considerable variation shown both as 
regards the different varieties and in the same variety in different seasons. 
“Shamrock”, which is very resistent to blight, is by no means so to 
Spongospora and „British Queen”, while very susceptible to blight, is 
apparently somewhat resistant to the latter organism. 
„Leaf-roll” also was again studied. Tubers containing Verticillium 
when planted gave rise to plants containing the fungus in their tissues, stet 
showed characteristic “roll” very strongly, and died more or less prema¬ 
turely. Other questions mentioned such as the resting spores of Phyto¬ 
phthora injestans , and the life history, characters and control of P. 
erythro septic a have been dealt with more fully elsewhere (Experiments 
with Bacillus melanogenes are also described). J. Ramsbottom (London). 
• ' i' 
BEILLE, L., Maladies et ennemis du Cacaoyer (Journ. Agric. Trop. 
1913, 13 . Nr. 144, 167—172; Nr. 145, 193—197; Nr. 146, 236—238). 
Ausführliche Zusammenstellung der Krankheiten der Cacao pflanze. 
Es werden nicht specialisierte Krankheiten (Wurzelkrankheit, Ab¬ 
trocknen der Zweige, Krebs, Hexenbesen, Verhärtung der Früchte), ferner 
vier dem Stamm eigene, vier der Wurzel eigene und zwei der Frucht 
eigene Krankheiten beschrieben. 
Eine große Anzahl von pilzlichen Schädlingen ist genannt. 
W. Herter (Berlin-Steglitz). 
KRAUS, €., Die gemeine Quecke \Agriopyrum repens P. B.] (Arb. 
Deutsch. Landwirtsch. Ges., Berlin 1912, H. 220, 152 pp; 19 Taf.). 
Die sehr eingehende Bearbeitung verdient auch an dieser Stelle Er¬ 
wähnung, da sie auf den Seiten 53—55 eine Zusammenstellung der auf 
der gemeinen Quecke sehr zahlreich auftretenden parasitischen Pilze bringt. 
Auf ihr finden sich 5 Brand-, 5 Rost-, 2 Mehltaupilze und außerdem 
Claviceps purpurea, Epichloë typhina , Sclerospora graminicola Schrot., 
Phyllachora graminis Zuck., Laestadia canificans Sacc., Ascochyta 
