20 THE MANGO IN POKTO EICO. 



necessary, except perhaps in some of the very diy localities on the 

 south side. 



In moist regions, where the mango fails to flower, it will be found 

 necessar}' to check the growth. This can be accomplished in a variety 

 of ways, the most primitive of which is mutilation of the trees or ring- 

 barking the smaller branches. This method is common in India, but 

 is not recommended as it disfigures the trees and may eventuall}^ kill 

 them. Concerning the eflicacy of this treatment, Mr. Horace Knight 

 reports that in Queensland trees 10 or 12 years old that had been bear- 

 ing only about a dozen fruits, after being ringbarked on their smaller 

 branches by opossums, bore such a crop that they had to be propped 

 to save them from breaking. The method recommended b}^ Mr. 

 Knight, however, is that of root pruning, which he thinks will 

 accomplish the same result without disfiguring the tree. 



Another method is to lay the roots bare for a time, and as soon 

 as the tree flowers cover them with rich earth. With trees grow- 

 ing in warm, moist localities Woodrow advocates the application of 

 salt at the end of the rainy season, about 10 pounds to the tree. This 

 doubtless acts in the same manner, and if efficacious would seem a 

 simple and economical method. 



Under favorable conditions the mango is ver}^ prolific. The tree 

 shown in PI. II was estimated to have in the neighborhood of 5,000 

 fruits at the time the photograph was taken, and trees quite as prolific 

 were seen near Cabo Rojo, P. R. ; while trees in southern Florida 

 before the freeze of 1880 were estimated to bear as high as 10,000 

 mangoes. From this it will be seen that with 25 to 100 trees per acre 

 enormous quantities of mangoes can be produced on very small tracts 

 of land, provided the right climatic conditions exist. 



DISEASES. 



The mango in Porto Rico seems almost entirely free from diseases 

 or the attacks of insects. On the north side of the island the skin of 

 the fruit is frequently disfigured by black spots, probably a fungus. 

 Though in no way injuring the eating qualit}' of the fruit these detract 

 from its appearance and would doubtless lessen its market value. In 

 the drier localities this discoloration was not observed, the fruit being 

 uniformly smooth and clear. Should it be deemed advisable to take 

 measures to prevent these spots, spraying with some fungicide would 

 doubtless accomplish the desired result. With the introduction of 

 better varieties, some of the diseases met with in other countries will 

 possibly make their appearance. In Trinidad the better varieties are 

 frequently affected by a disease that causes the pulp around the seed 

 to darken and become sour and entirely inedible. It seems not 

 improbable that the moist conditions prevalent in Trinidad may con- 

 duce to this disease, in which case the dry south side of Porto Rico 

 will have an additional advantaue. 



