Pflanzenkrankheiten. 347 



plants which are attacked inereases. In this paper the author shows 

 a decaj r which attacks watermelons {Citrullus vulgaris) in transit to 

 be caused by a fungus belonging to this genus. The parasite was 

 isolated from fruits in which the dccay was just beginn ing to be 

 apparent and the pure culture was inoculated into sound water- 

 melons at separated points, at each of which the characteristic rot 

 was reproduced. This Diplodia injur} 7- is the cause of seriousloss in 

 the watermelon industry. V r an der Lek (Wageningen). 



Taubenhaus, J. J., Soilstain, or scurf, of the sweet po- 

 tato. (Journ. A<jric. Research, p. 995— 1001. PL LXXVI— LXXVII. 

 1916.) 



Soilstain, or scurf of the sweet potato is not a disease to be 

 feared in the sense that it may produce a direct rot in the mature 

 roots; nevertheless, it is economically important. It is a disease of 

 the epidermis of the root and is probably generally distributed; it 

 is more abundant in the heavier soils, especially where manure is 

 used as a fertilizer. In storage the disease spreads by contact and 

 is favored by moist, poorly ventilated houses. The parasite, Moni- 

 lochaetes infuscans, is difficult' to culture, because it is a very slow 

 grower and is readily overrun by saprophytes. Pure cultures of 

 the fungus were finally obtained from plantings of young minute 

 spots. Of 300 such spots 10 per cent yielded colonies of the causa- 

 tive organism; the fungus did not appear until three weeks after 

 culturing. The conidiophores of M. infuscans are distinct from the 

 mycelium, the older growth of which is also dark. The conidia are 

 borne in chains which readity break up when moistened or distur- 

 bed. Using pure cultures of the fungus, the writer reproduced the 

 disease several times at will. Van der Lek (Wageningen). 



Weir, J. R., Hypoderma deformans, an undescribed needle 

 fungus ofwestern yellow pine. (Journ. Agric. Research. VI. 

 p. 277—288. Fig. 1-4. PL XXXII. 1916) 



A disease on the needles of yellow- pine {Pinus ponderosa) in 

 many parts of the Northwest, is found to be caused by a fungus 

 which is described as a new species under the name „Bypcderma 

 deformans". H. deformans is a true parasite and attacks the foliage 

 of all age classes. An attempt to grow the fungus on culture media 

 failed, the spores in every case germinated but in the course of 

 six to eight months, after frequent transfers, the mycelium died. 

 Inoculation experiments were set up by shaking diseased needles 

 in water; the mixture was sprayed over yellow-pine seedlings. 



Other experiments were performed by binding infected needles 

 on seedlings and also by similar quantities of needles which had 

 died a normal cause. These experiments proved the parasitism of 

 the fungus and its inability to act as a saprophyte. Because of the 

 Penetration of the mycelium in the tissues of the stems of the host, 

 the terminal shoots do not attain their proper development, but 

 become stunted and deformed, eventually producing a witches' 

 broom. Upto the present time the disease has not been found in 

 the forest nursery, but it may be regarded as a possible nursery 

 disease. Since the vegetative mycelium of the fungus may hiber 

 nate in the shoots of seedlings after the infected needles have fal 



