80 DISEASES 



also do the shells and beans left lying about in the plan- 

 tation. 



The writer has noticed, both in West Africa and in San 

 Thome, frequent instances of cocoa fruits having been 

 torn from the trees and carried completely away by 

 monkeys. Squirrels are also troublesome in these two 

 districts, as well as in Trinidad and Ceylon. Considerable 

 damage is caused by squirrels in Ceylon ; the 1907 annual 

 report upon the Experiment Station shows that more 

 than 60,000 cocoa fruits were damaged during that 

 year in the experiment plots. 



Methods of Destroying Rats. — The ravages caused by 

 rats are, however, far greater than those due to both 

 monkeys and squirrels. 



The losses which San Thome planters annually sustain 

 from the depredations of rats must be enormous. One 

 authority has estimated it at 10,000,000 francs. This 

 is probably an exaggeration. Some idea of the number 

 of rats which infest the San Thome cocoa estates may 

 be gathered from the fact that, the manager of one of 

 these estates assured the writer, 16,000 rats were annually 

 destroyed on the property. Other countries where rats 

 are destructive to the cocoa crop are : Trinidad, Martinique, 

 and Samoa. 



The most destructive species in San Thom6 are Mus 

 ratus and M. decumanus ; the former is common in Trini- 

 dad, as well as the " pouched rat," Heteromys anomalus, 

 Thompson, and the "spiny rat," Loncheres guiance, 

 Thos. 



It is thus apparent that the planter must look upon 

 the rat as a formidable deterrent to profitable cocoa 

 cultivation, and when it appears in his plantation it must 

 be energetically combated. 



Monkeys, squirrels, and rats may all be caught in traps ; 

 poisoned bait can also be effectively used. In San 

 Thom6 large numbers of dogs are trained to hunt the 

 rats. 



Farmer's Bulletin, No. 297 of the United States De- 

 partment of Agriculture, suggests the following poisoned 

 baits for the destruction of rats : One part barium 

 carbonate, or barytes, mixed with four parts of meal 

 into the form of dough ; or one part barytes mixed with 

 seven parts of oatmeal and made into a stiff paste. This 



