362 Pflanzenkrankheiten. — Bacteriologie. 



nasturtium with a virulent strain of B. solanacearum, isolated from 

 tobacco, gave typical nasturtium wilt. 



Infection takes place from infected soil through broken rodts, 

 but stomatal infection has also been demonstrated. 



This paper adds another family to those already known to be 

 subject of B. solanacearum. Described from the tomato, the potato, 

 and the egg plant in 1896 by Dr. Erwin F. Smith, this organism 

 has now been proved infectious to one or more species of each of 

 the following families: Solanaceae, Compositae, Verbenaceae , Euphor- 

 biaceae, Bignoniaceae and Geraniaceae. Jongmans. 



Gioyer, W. O., Ascochyta clematidina, the cause ofstera-rot 

 and leaf-spot of Clematis. (Journ. Agric. Research. IV. p. 331 — 

 342. PL 50—54. 1915.) 



The stem-rot and leaf-spot of Clematis is caused by the fungus 

 Ascochyta clematidina. The plants are killed by the growth of the 

 fungus down the petiole into the stems, thus girdling the plant at 

 the node. The stem may be girdled also by the lesions anywhere 

 on the internodes. Dead stubs left on the vines are a means of 

 holding the disease over a period of time. New shoots may be for- 

 med below the girdled region, but the downward progress of the 

 fungus ultimately kills the plants if the diseased tissue is not 

 removed. 



Overwintering out of doors does not kill the fungus in cultures 

 or on dead vines. Whenever the temperature permits, the fungus 

 resumes its growth. 



The fungus is readily isolated and grows well on the media 

 generally employed in the laboratory. 



The disease has been successfully produced by inoculating Cle- 

 matis paniculata and C. jackmanni with the mycelium from pure 

 cultures. The fungus has been reisolated from such inoculations, 

 and with it lesions are again produced on other vines. 



A. clematina is not related to other common species of the 

 genus Ascochyta, for inoculations made in growing stems of bean, 

 pea, muskmelon, pumpkin, eggplant, and the young shoots of elm 

 gave negative results. 



Spraying the plant with spores will produce the leaf-spot. 

 More Spots are produced when the spores are placed on the lower 

 surface of the leaf than on the upper. A temperature of 23° is 

 more favorable for the production of the leaf-spot than a tempera- 

 ture of 10° C. 



The matting of the vines produces a condition most favorable 

 for the spread of the disease. 



Several methods are worked out to check the disease. 



Jongmans. 



Boekhout, F. W. J. und J. J. O. de Vries. Ueber den „Kny- 

 per"-Fehler imEdamer Käse.(Cbl. Bakt.2.XLVI.p.497— 502. 

 1916.) 

 Dieser Fehler — Blähungen in weicher, Rissbildung in harter 

 Käsemasse — kommt dann zu stände, wenn der den Buttersäure- 

 Bakterien gebotene Salpeter zerstört wird. So konnten Verff. durch 

 gleichzeitige Impfung mit den beiden salpeterzerstörenden Bak- 



