12 DAMAGE TO SUGAR CANE BY THE SUGAK-CANE BORER. 



It should be noted as having a bearing on all of these analyses 

 that the lower the purity of the juice the lower is the percentage 

 of total sucrose that is recoverable in the form of sugar. Therefore 

 the percentage loss of sugar in the impure samples somewhat exceeds 

 the loss of sucrose. The sucrose which can not be recovered is 

 approximately equal in amount to the glucose present. On this 

 basis the present experiment would show a production of 176.26 

 pounds sugar per ton for the borer-free cane, while the borer-infested 

 cane would give 138.97 pounds sugar, a loss of 37.29 pounds per 

 ton of cane, equaling a loss of 21.16 per cent sugar, which is 1.83 

 per cent in excess of the sucrose loss. 



It may be computed from the figures in Table VII that an acre of 

 borer-free cane yielding 25 tons of cane of the above quality would 

 yield 4,716.25 pounds sucrose ])er acre, while if it were infested to 

 the same degree by borers, the yield under similar conditions would 

 be 23,92 tons of cane and 3,637,75 pounds of sucrose per acre — a 

 loss of 1,078,50 pounds sucrose per acre. 



SUMMARY. 



The sugar-cane borer damages cane in the field by destroying a 

 considerable percentage of the eyes, thus reducing the stand of i)lant 

 cane; by stunting the growth of the cane, omng to the physical 

 injury of the stem; by admitting fungous diseases through the 

 wounds in the stem; and is the main cause of injury by the wind, 

 owing to the weakening of the stalk due to the tunnels and burrows. 

 These classes of injury have been appreciated by planters. It now 

 develops that there is another and very important class of injury 

 which has been overlooked. This is the reduction of both the 

 quantity and quality of the juice, which is dealt with specially in 

 this circular. It becomes evident that both the planters and the man- 

 ufacturers are vitally interested in the work of the sugar-cane borer. 

 Investigations of methods of control in the field are now under way. 

 The results will be published in due time. In the meantime planters 

 are referred to the bulletin on the subject (Bulletin 70), by W. C. 

 Stubbs and H. A. Morgan, of the Louisiana Experiment Station. 



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