SUGAR-CANE FUNGI AND DISEASES OF PORTO RICO.^ 



By John B. Johnston, formerly Pathologist and John A. Stevenson, Pathologist 



Insular Experiment Station. 



INTEODUCTION. 

 THE NEED FOR INVESTIGATIONS OF CANE FUNGI. 



.The sugar cane {Saccharum officinarum) as an economic crop 

 lias been grown in Porto Rico since at least 1548, when the first mill 

 was erected and during all this i)eriod has doubtless suffered from 

 the various common diseases, although no published reports are avail- 

 able until about 1870-80. During this latter period there occurred a 

 most serious epidemic in the western section of the Island, occasioning 

 heavy loss. From that time on, although the epidemic as such passed, 

 there was continued loss through cane diseases, combatted as inform- 

 ation given by planters indicates, by change of land and the intro- 

 duction of new varieties. Following the American occupation, which 

 gave a great impetus to the industry, the greatly increased areas 

 given over to cane have meant increased losses from fungus attacks, 

 more especially where the extra care in cultivation, so necessary 

 when one crop is grown continuously, has not been given. 



In some years it has been common to find whole fields ruined 

 by one or another disease; and in certain areas it is impossible to 

 grow more than one or two crops of cane without a period of rest, 

 in contrast to many parts of Cuba and Santo Domingo where an 

 indefinite number of ratoon crops are obtained without replanting. 



' T)iis paper was originally prepared by Mr. Johnston previous to his resignation in 

 September, 1914, as pathologist of the Insular Experiment Station and was at that time 

 nearly complete, including drawings and photographs. Circumstances not having permitted 

 of its publication before the present date it has now been completely revised and rewritten 

 to permit of the inclusion of all data obtained in the past three years by the junior author, 

 who has carried on the work since Mr. Johnston's departure as well as having been con- 

 nected with the pro,iect for a year previous to that time as assistant pathologist. A con- 

 siderable number of additional species, some of them new, have been added, and others 

 orginally only provisionally named have been determined and inserted, together with many 

 supplementary notes and observations on the other species. The drawings are the work of 

 the senior author, the photographs were for the most part originally prepared .jointly, and 

 the present selections and arrangements have been by the junior author, including some new 

 additions. 



Acknowledgment is made for assistance in the matter of determinations to Mrs. F. W. 

 Patterson, U. S. Department of Agriculture; Dr. E. A. Burt, Missouri Botanical Garden; 

 Dr. F. J. Seaver, and Dr. W. A. Murrill, New York Botanical Garden; Prof. C. G. Lloyd: 

 and Dr. W. C. Sturgis. Further acknowledgment is made in connection with the description 

 of each species on which help has been had. 



The junior author assumes responsibility for the form in which the paper is here pre- 

 sented as well as for any errors that may occur. 



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