FUNGUS DISEASES OF COFFEE IN PORTO RICO. 



INTRODUCTION. 



Fungus diseases of coffee are common in Porto Rico, and in 

 many instances destructive. The reduction in the yield and con- 

 sequent loss which result from their activity are not definitely 

 known, but they must be large. The small crop of many plan- 

 tations is no doubt due to the constant though often inconspicuous 

 defoliation and killing of the trees which they cause. It is desired 

 not only to attract attention to these diseases, but to suggest such 

 means of getting rid of them as have been shown by experience to be 

 of value. The excellent but costly methods of fighting disease, such 

 as those practiced in the case of the intensively cultivated citrus 

 fruits, are not to be recommended so unhesitatingly for coffee, the 

 profits from which are not so great as to make the cost of production 

 of small importance. Moreover, coffee is often grown in extended 

 plantings in mountainous country where it receives so little cultiva- 

 tion as to be hardly more than a wild plant. Wliere these conditions 

 exist it is not likely that any more attention will be given the diseases 

 than in the past. But there are other, usually smaller, plantations 

 where it would seem worth while to take advantage of any measures 

 of value in keeping up their present good condition, either by fight- 

 ing those diseases that have already become established or keeping 

 them from the healthy young plantings. 



It is expected also that a publication of this nature will be of value 

 in dispelling the idea entertained by some planters that the diseases 

 of this plant have been so neglected as to be practically unknown, but 

 only await scientific study to be entirely done away with. Some of 

 the coffee diseases of Porto Rico are common to other coffee-growing 

 countries, and were first described many years ago. Suggestions as 

 to their control have been made from time to time by laboratory 

 workers, but apparently the methods have never been tried by grow- 

 ers, else such value as these suggestions possess would have been pre- 

 viously realized. The knowledge of the life history of the parasitic 

 organisms causing the diseases has led to no entirely successful 

 method for their control, if this is taken to mean some way in which 

 the diseases may be ver}^ easily eradicated without some expense and 

 careful attention in application. 



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