21 



removed should be ditched about, if they occur in the diseased areas 

 that are to be treated, as they sometimes seem to harbor the disease. 

 The guava and guama, which are frequently killed by borers, leave 

 many such stumps, and for this reason these trees are undesirable 

 as shade trees. If the ground is to be broken up, which is an ad- 

 vantage if lime is to be added, this should be done immediately after 

 the cleaning. The ditches should be a foot wide and of somewhat 

 greater depth. Care should be taken to examine the bases of the 

 trunks of all the trees to be inclosed by ditches in order to make 

 sure that no diseased trees have been left inside from which the dis- 

 ease can be communicated to the others. Such an examination will 

 usually show some of the healthiest looking trees to be affected with 

 the disease, often being girdled just below the surface of the soil. 

 The length of time that such trees can live and bear fruit, after 

 having been girdled, is indicated by the fact that a coffee tree of 

 which the bark was removed for a space of 4 inches about the base, 

 the wound having been painted with carbolineum to kill any living 

 tissue from which growth might set up, lived for 23 months, bearing 

 one full and one partial crop. Any tree showing a diseased patch 

 near the crown should be removed. Ditching about the diseased 

 areas, together with the gathering and destruction of the diseased 

 trees and vegetable debris, constitutes the most important step in 

 controlling the disease. After the earth has been broken up unslaked 

 lime may be applied, as already described, care being taken not to 

 place it too close to the trees. If applied in the dry season it should 

 be sprinkled with water to slake it after mixing with the soil. It 

 is not likely that a quantity of unslaked lime less than that used in 

 the experiment (500 grams per square meter) w^ould be effective. 



To summarize, ditching is recommended as preventing the fungus 

 from passing from diseased to healthy trees; cleaning up vegetable 

 debris and removal of diseased or dead coffee trees and the addition 

 of lime or some other substance to the soil are measures of some value 

 in combating the fungus. The ditches should be cleaned out from 

 time to time and vegetable material prevented from accumulating 

 in the places affected with the disease. Such measures are of special 

 value where only a few diseased trees are found among otherwise 

 healthy plantings. Where the centers of infection are too numerous 

 it may be useless to protect with ditches and even less so to use the 

 other sanitary measures mentioned above except, perhaps, the re- 

 moval and destruction of diseased trees as soon as observed. 



BERBY SPOT (Cercospora coffeicola). 



This spot of the berry is troublesome since it causes the fleshy 

 part of the fruit to adhere to the parchment, thus making the process 

 of preparation more difficult. It is also the cause, at least indirectly, 



