86 THE BANANA 



published in April 1911 under the title, " A Bacterial 

 Disease of Bananas and Plantains," in " Phytopathology," 

 and reprinted by the Board of Agriculture of Trinidad. 

 The disease is caused by a bacterium (Bacillus musce). This 

 organism was isolated from diseased plants, and used to 

 infect other varieties and species of Musa. The red banana 

 and the dwarf or China banana (Musa Cavendishii) suc- 

 cumbed to inoculation. The Manila hemp plant (Musa 

 textilis) proved to be quite resistant, and although some of 

 the inoculated plants of the common banana (Gros Michel) 

 died, the progress of the disease was slow, some remained 

 apparently quite healthy, and the fact that this variety 

 has never been found to be naturally affected leads Rorer 

 to believe that it is, as has been stated above, practically 

 immune from this particular disease. This disease has been 

 easily kept under control in Trinidad on several small 

 plantings of plantains and bananas by sanitary measures 

 alone. As soon as a diseased plant is noticed, it is dug 

 up and burnt on the spot, and all tools and instruments 

 used in the work are sterilized by fire. All suckers are 

 examined before planting. 



The symptoms of the disease, according to Rorer, are 

 as follows : " The presence of the disease is as a rule first 

 detected in the lower leaves. The leaf -blades droop a 

 little more than usual and have a slightly yellowish tinge, 

 symptoms very similar to those brought about by drought. 

 Soon, however, the stalk of one of the leaves gives way 

 just at the base of the leaf -blade, and all the other leaves 

 quickly break down in a similar manner. Eventually the 

 terminal leaf too bends over, and the plant dies and rots 

 down to the ground. 



" Transverse sections of the trunk show that practically 

 all the vessels are discoloured, the colour ranging from 

 pale yellow to dark brown or bluish black, and filled with 

 bacteria. The discoloured bundles run back into the true 

 stem and thence into the young suckers and buds. Some- 

 times in badly diseased plants the tissues of the leaf- 

 stalks and stems are broken down completely, so that 



