2 DAMAGE TO SUGAR CANE BY THE SUGAE-CANE BOEEK. 



uninfested and infested for a number of consecutive j^ears, he esti- 

 mated the damage at $136,335 for tliree years on plant cane alone, 

 or $45,445 per year, nearly $1,000 per day during the grinding season 

 for tills one factory. When it is considered that most of the area 

 devoted to cane growing in Louisiana is infested with the borer, it can 

 easily be appreciated from the above figures that the total financial 

 loss must be enormous. 



One of the special fines of work planned by Mt. D. L. Van Dine, 

 when the laboratory for the investigation of sugar-cane insects was 

 established by tliis Bureau in 1910, was the determination of the 

 various classes of injury caused by the cane borer. Observations and 

 experiments were conducted by the writer in 1910. It was discovered 

 that the borer is responsible for much more injury than is apparent at 

 first sight. Its harmful work begms wdth the destruction of eyes 

 of seed cane, reducing the stand during the foUowing year; con- 

 tinues through the growing season of the cane by stunting its growth, 

 and causing damage from mndstorms, owing to the weakening of the 

 stalk due to the burrows and girdles; and ends by causing a much 

 lower percentage of juice, wliich is again of a much poorer quality in 

 infested canes than in uninfested canes. The last is an important 

 form of injury, wliich appears to have been overlooked by investigators 

 and planters. 



Moreover, the holes made by the cane borers are the cliief means 

 of entrance to the stalk afforded the various fungous diseases of 

 the sugar cane. The tonnage yield per acre is reduced by borers, 

 and the average weight of canes otherwise similar in appearance is 

 found to be reduced by borer infestation. 



These points will be explained in detail under the following head- 

 ings: Injury to seed cane; injury to growing cane; injury to mature 

 cane and juice. 



INJURY TO SEED CANE BY THE SUGAR-CANE BORER. 



The buds of cane are favorite places for the attack of the young 

 borers while the stalk is growing, due to the softness of the tissue 

 compared to the woodiness of the rind of the cane stalk in other 

 locations. The young larvse of the sugar-cane borer will enter the 

 buds or eyes of the cane, and in nearly every case the attack wtU 

 result in the destruction of the bud. Frequently canes will be seen 

 in wliich more than 50 per cent of the buds have been destroyed by 

 the borer. Of course, many borers enter the stalk at other places, 

 around and between the joints, as an average cane will contain only 

 from 6 to 15 joints, while canes will often be found with from 6 to 10 

 borer holes in a single joint. In nearly every case of severe infesta- 



