292 THE BANANA 



four headings, namely, exclusion, protection, eradication, 

 and immunization. 



1. Exclusion. Exclusion of diseased plants or other 

 infected material by means of legislation would only be 

 of value (1) in countries where the disease is not present, 

 but in which conditions are such as favour the disease; 

 (2) in similar regions where the disease is not yet firmly 

 established; (3) where it is partly held in check by climatic 

 conditions. 



This last division would include Jamaica, Porto Rico, 

 and perhaps Cuba. Laws with respect to such quarantine 

 already exist in Jamaica. Besides regulations to prevent 

 the introduction into the island of any new source of infec- 

 tion, it is required by law that any person occupying land 

 on which plants infected with wilt disease exist must give 

 notice of the same to the Director of Agriculture, who then 

 directs that the treatment prescribed by law be carried 

 out. This consists of the destruction by fire of the diseased 

 plant or plants, and other plants around them within a 

 distance of 22 yards, after which the infected 

 area is fenced in, and a local quarantine established for 

 one year or more at the discretion of the Director. Inves- 

 tigation of the life-history of the parasite shows that these 

 laws are amply justified. Even, however, in places where 

 such measures are applicable, they appear only calculated 

 to alleviate the situation until some other method may be 

 found to eliminate the disease. 



2. Protection. Protection may be defined as the inter- 

 position of some effective barrier between the susceptible 

 part of the host and the inoculating germs of the disease. 

 As has been mentioned above, the susceptible parts of the 

 banana plant are below the surface of the ground. Any 

 method of attack, therefore, similar in principle to the 

 spraying of the parts above ground by fungicides, is of no 

 value. 



3. Eradication. Practically all efforts so far made in 

 attempting to control this disease have been directed 

 along the lines of eradicating the parasite. 



