Ill 



DISEASES AND PESTS 



33 



intercourse between peoples add still more to the danger, 

 having, for instance, introduced smallpox to America and 

 syphilis to the Old World. The situation of any crop 

 is in principle identical with that of man. When 

 plants are cultivated on a small scale, and are widely 

 and sparsely scattered, they are comparatively safe, but 

 the development of a great industry in one of them 

 multiplies its danger from disease. And this is made 

 greater still by commerce ; as, for instance, the coffee 

 rust would probably not have reached Java and the 

 Philippines by natural means of dissemination. 



The most of the diseases of the coco-nut are like 

 the plague of man in having other hosts as well, and 

 may therefore attack a solitary and healthy tree. But 

 every one of its infectious or epidemic diseases, so far 

 as known, unlike the malaria of man, or the classic 

 rust of wheat, can go through its whole life-cycle in 

 the one host, and spreads directly from one coco-nut 

 tree to another. Plantation cultivation on a large 

 scale furnishes ideal conditions for epidemics. When 

 great areas are brought under almost continuous 

 cultivation, as in Ceylon, on the Godaveri delta in 

 India, on the coast of Trinidad, and in Central Luzon, 

 the danger from disease grows at least apace with the 

 industry. The fact that almost nothing was published 

 on coco-nut diseases until the last few years, or that 

 as recently as 1906 Prudhomme could state that the 

 important enemies and parasites are all animals, does 

 not prove that fungus and bacterial pests previously 

 did not exist and do damage. The bud rot in the 

 West Indies and in Luzon existed so long before it 

 attracted outside attention that nothing is known 

 about its origin or first appearance in either region. 

 But these and other diseases have increased very much 

 in destructiveness, and as the opportunity for their 

 spread improves they must be expected to become 

 yearly more destructive, unless they are guarded 

 against with a care which was formerly not suspected 

 of being necessary. 



