690 



numerous small white specks at times of great drought, while in Deli the 

 mosaic disease is observable immediately after sharp rainstorms. The 

 cause is looked for in conditions similar to those in the mosaic disease. 



White Rust of Tobacco. 

 A further phenomenon has been confused with the mosaic disease 

 which is called "White Rust."' Delacroix^ has called attention to the fact 

 that, in this the mature leaves, and not the young ones, become sick first. 

 The spots are more numerous but are smaller and stand out in sharp relief. 

 Ultimately they are bounded by a cork layer. The cause is said to be 

 a micro-organism. Bacillus macnlkola. 



The Disease of the Peanut in German-East Africa. 

 According to Karosek- Arachis hypogaea, one of the most important 

 cultivated plants of the East African colony, is in general but little attacked 

 by disease. In the neighborhood of Tanga and Lindi, however, a phenom- 

 enon has now appeared to a considerable extent which recalls the mosaic 

 disease. The leaves, blossoms and fruit remain small, the yield is scanty ; 

 whitish, irregular spots appear on the leaves, deforming them somewhat. 

 The leaves finally become brown and die. Fungi have been found and any 

 lack of nutrition is out of the question. 



The Shrivelling Disease of the Mulberry. 



This disease, at present widely distributed through Japan, which surely 

 will be found later in Europe, has only been observed more exactly for 

 possibly the last twenty or thirty years and has been studied earnestly only 

 during the last ten years. According to Suzuki^, whose description of the 

 disease we follow, it is called Jshikubyo or Shikuyobyo in Japan. Like the 

 mosaic disease, this shrivelling disease also occurs most extensively in the 

 tender leaved and quick growing varieties. Within the same cultural 

 varieties the individuals suffer most strongly wdiich receive too much liquid 

 fertilizer, while trees planted in poor soil, or in mountainous regions, are 

 almost free from it. 



The fact that the disease became noticeable at about the time when 

 the so-called "pruning method" was universally introduced into Japan is of 

 especial importance. This method consists in the cutting down of the 

 trunks, or branches, at the time of the most luxuriant leaf development 

 (May to June), close to the soil when the plant is three years old. The. 

 stock at once produces new, luxuriant shoots which by September have 

 become 5 to 6 feet tall. These branches, in the following summer, are cut 

 back again, either close to the soil or several feet above the surface. Speci- 

 mens, which have been cut back for a long time, suffer less from the disease 



1 Delacroix, G., La rouille blanche du tabac et la nielle, eta Compt. rend. 

 1905, CXL, p. G75. 



2 Karosak, A., Eine neue Krankheit der Erdniisse in Deutsch-Ostafrika. 

 Gartenflora 1904, p. 611. 



3 Suzuki, v., Chemische und physiologrische Studien liber die Schrumpfkrank- 

 heit des Maulbeerbaumes, eine in Japan sehr weit verbreitete Krankheit. Zeitschr. 

 f. Pflanzenkrankh. 1902, p. 203. 



