to a weakness in the cane due either to a weak soil or to drought 

 or to excessive water. Apparently a variety of these conditions 

 brings about much the same effect in cane. 



Aside from the occurrence of the rind fungus in large mature 

 canes, it is not uncommon to find it abundant in fields of cane that 

 have been stunted through the presence of root disease, or some un- 

 toward soil condition. This is especially true in old ratoons that 

 are running down. In Canovanas in 1912 an entire field of cane 

 failed to grow large and vigorous and before maturity almost the 

 entire field ^vas infected with this fungus and Avas a complete loss. 

 In adjacent fields first crops have been obtained, but there, too, the 

 ratoon crops have been lost in the same way. 



In all cases in Porto Rico an infection with the rind fungus seems 

 to be preceded by a weakening of the vitality of the cane through 

 some other untoward condition. It happens, however, that these 

 conditions cannot always be foreseen, and therefore the rind fungus 

 must be considered a serious obstacle to the best results among the 

 sugar planters. These various untoward conditions in themselves do 

 not begin to have the effect that they do together with the rind 

 fungus. 



Cane may suffer from root disease, but does not rot out unless 

 affected by the rind fungus also. 



Cane may suffer from drought, but it does not deteriorate unless 

 attacked by the rind fungus in addition. 



Cane may suffer from floods, but that does not render it worth- 

 less as does a severe infection of the rind fungus. 



Altogether the field investigations appear to demonstrate that 

 31 elanco Ilium sacchari is capable of doing great damage in mature 

 canes in Porto Rico. 



INOCULATIONS WITH THE RIND FUNGUS. 



Inoculations with pure cultures of the rind fungus have been 

 made into green canes and into almost mature canes, but in no case 

 was there any visible infection. In all these inoculations the cane 

 was vigorous and the inoculating wounds were slight. This would 

 tend to show that vigorous cane was not infected by tliis disease. 

 No inoculating experiments have been made on weak canes. 



FIELD INVESTIGATIONS IN SANTO DOMINGO. 



Examination of the cane fields at La Komana, San Pedro de Ma- 

 eoris, and Santo Domingo city show the rind fungus to be common 

 but not doing much damage. It is present only in canes which have 



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