CITRUS CULTURE IX PORTO RICO 



29 



Bebudding which was done years ago has been the cause of much 

 trouble. The large trunks were not always properly cut and the 

 scars properly covered ; as a result the trees started to rot and could 

 be saved only by means of tree surgery. This consists in removing 

 all dead wood and filling the cavity with some material such as 

 Portland cement. Cement is not always satisfactory, because it 

 usually shrinks away from the sides of the cavity. Once water gets 

 between the cement and the tissue the decay proceeds more rapidly 

 than ever. Asphalt has given better results than cement, but is satis- 

 factory only when used by skilled workmen. The cavities may also 

 be left open provided they are well cleaned out, waterproofed, and 

 drained. 



Some growers plant three or four seedlings around an old dis- 

 eased tree and inarch them into the trunk. By means of this treat- 



Figure 16. — Tree which was planted on level ground. 

 Crown roots are not visible and the trunk is infected with 

 gum disease 



ment and the giving of proper attention to wounds, the life of the 

 tree may be prolonged. Wounds should always be treated with 

 Bordeaux paste, or some wood preservative that will not injure the 

 live tissue. Of late years gas tar has been used by many growers. 

 It is not always suitable, but the grade produced and sold in San 

 Juan does not seem to injure the live tissue of the tree. In choosing 

 a wound dressing it is well to keep in mind the fact that such mate- 

 rials as Bordeaux paste and other similar antiseptics do not make 

 the wound water and air tight. They must be followed by an appli- 

 cation of tar, asphalt, or some other preparation that will form a 

 perfect permanent seal. 



Wither tip or die-back of the small branches causes considerable 

 loss in some of the groves. Like the various gum diseases of the 

 trunk, wither tip is associated with fungi. Losses from it are small 



