APPENDIX 291 



In such regions the intense heat and dryness of the surface 

 of the soil would make the survival of the wind-borne 

 spores impossible. In southern Jamaica the soil becomes 

 so hot and dry that planters invariably set the bulbs 

 with about 1 foot of the " stem " still attached, so that 

 this succulent stem, when it rots, will furnish moisture 

 for the young shoot, and prevent its death by " boiling," 

 as it is termed, though " baking " would be a more de- 

 scriptive term. It is believed, therefore, that the disease 

 need never be feared in these dry regions. 



In countries where there are no well-marked wet and 

 dry seasons that is, where the rain is more or less evenly 

 distributed throughout the year the best conditions for 

 the spread of the fungus exist. This is attested by the 

 virulence of the disease in the banana districts of Panama 

 and Costa Rica. 



In Surinam, where the annual precipitation is very 

 heavy, and the rains are distributed over practically the 

 whole year, the disease spread over the entire country in 

 the short space of four years. In such regions it is not only 

 highly infectious, but extremely virulent and aggressive. 



CONTROL 



The present knowledge of the life-history of the disease- 

 producing organism leads to the conclusion that the elimi- 

 nation of the disease as a source of injury to banana planta- 

 tions, in countries where conditions are favourable to it, 

 cannot be based on an attempt to eradicate the parasite. 

 Any direct method of attack, such as protecting the plants 

 by the application of fungicides, or eradication of the 

 parasite in the soil by any method now in use, is out of the 

 question. Sterilization of the soil is not economically 

 practicable at the present price of bananas. Selection 

 of disease-free bulbs is of value only where they are to be 

 planted in soil which is not already infected. Control 

 measures for this disease, as for other diseases of plants, 

 would naturally group themselves under one or more of 



