WILT-DISEASES OF TOBACCO. 



(Sumatran Slime-disease of Tobacco; Granville Wilt; Japanese Stem-rot, etc.) 



A portion, at least, of this chapter belongs with the preceding. It is here kept separate, 

 partly for the convenience of the reader, partly because it was written up in this form, my 

 own cross-inoculations (up to 1908) not having been as conclusive regarding exact identity 

 as those reported by Dr. Hunger; and partly because of contradictory statements by Uyeda 

 respecting the cause of the Japanese disease. The whole subject of the etiology of these 

 tobacco-rots needs very careful inquiry. Possibly we have to do with several different wilt- 

 diseases.* In 1908 and 1909, the writer obtained conclusive cross-inoculations on tomatoes, 

 using the North Carolina tobacco organism. In 1909, Stevens sent me a photograph 

 showing the tomato-disease occurring in tobacco fields (fig. 115). 



THE DUTCH EAST INDIAN DISEASE. 

 HISTORY AND ETIOLOGY. 



In 1892, from studies made in Buitenzorg, on specimens received from Sumatra, Janse 

 correctly attributed to bacteria the tobacco-disease subsequently studied by van Breda 

 de Haan, by Hunger, by Jensen, and by Honing. 



Janse describes the brown sunken stripes on the surface of the stem and the brown 

 stain in the vessels, and notes the fact that they are plugged with a grayish mass of bacteria 

 which stained readily in picric-acid-anilin-blue. He also examined microscopically the 

 destruction of bark, bast, and pith, and saw closed cavities extending long distances. These 

 cavities were filled with the bacteria in enormous quantities. Similar lesions occupied by 

 the bacteria were seen by him in the leaf-stalk, the midrib, and the side-veins of the leaves. 

 Morphologically, all the bacteria appeared to be of one sort, were quite short, so as more to 

 resemble coccus forms than rods, and measured 0.7/* in length. He did not find the bacterial 

 plugging of the vessels in all of the diseased plants, but this is not to be wondered at, as 

 he did not himself select the material, and a fungous disease appears to have been present 

 also on the plants both in the seed-beds and in the fields. Most of his observations were 

 made on alcoholic material, and no cultures or inoculations were undertaken. His general 

 conclusion is sufficiently shown by the following paragraph : 



From these anatomical studies we may conclude, tentatively, that the disease here considered is 

 probably caused by bacteria. These appear to infect the leaf locally (plaatselijk), developing in the 

 cells of the leaf-tissues, which are destroyed, and subsequently extending further into the plant, 

 either by way of the vessels, or from cell to cell. In the first case they enter the stem, and subse- 

 quently appear outside the vessels (possibly by the normal rupture of the primary vessels due to 

 elongation of the stem), and make their way between and into the adjacent cells (bast and pith) where 

 they may develop into great colonies, and by destruction of the tissues form cavities which one finds 

 on examination to be entirely filled with bacterial masses. 



Mycelium was occasionally found with the bacteria, but Janse is inclined to think it 

 secondary. 



In 1898, in the Dutch East Indian Journal Teysmannia, Dr. van Breda de Haan 

 described a disease of tobacco prevalent in Sumatra. He speaks of it as the slime-sickness, 

 a "specific decay," resulting in the death of the plant. He attributes it to wounds of various 

 kinds followed by the entrance of a specific bacterium. The bulk of the long paper is 



*Since this mas written Honing has cleared up the Dutch East Indian situation. 

 220 



