THE SUGAR-CANE MOTH BORER. 5 



As calculated from the figures of Mr. T. C. Barber, a similarly 

 high loss is obtained. Mr. Barber estimates a total loss of 1,078 

 pounds of sucrose per acre where canes are all bored, as they some- 

 times are. The present writers estimate the loss of 96 test sugar 

 as 1,082.33 pounds per acre. The average price of this grade of sugar 

 on the New Orleans market during the 11 years from 1900 to 1913, 

 inclusive, was approximately 3.87 cents per pound. At this price the 

 money loss where all canes are bored is $41.88 per acre. 



During the six-year period from 1912 to 1917, inclusive, in which 

 observations have been made, the average infestation has been about 

 §8 per cent of all the canes in the infested area in Louisiana, which 

 includes the whole sugar belt, except the parishes of Rapides and 

 most of Avoyelles, or about 300,000 acres planted in sugar cane. 

 Fifty-eight per cent of the maximum loss ($41.88) is $24.29 per acre. 

 For 300,000 acres it reaches the high figure of $7,287,000. The losses 

 in southern Florida and the lower Rio Grande Valley, in Texas, 

 would correspond to the acreage. The infestation in Texas is always 

 high. 



These figures do not take into consideration the loss due to injury 

 to corn, which must be considerable but is difficult to estimate. 



EFFECT ON YOUNG CANE—" DEAD HEARTS." 



The first injury of the moth borer to the young sugar-cane plant 

 produces what is known as the " dead heart." This injury is illus- 

 trated in Plate I. Among plants from 6 inches to 3 feet in height 

 some usually are to be found in which the outer leaves are a healthy 

 green while the young inner whorl is yellow and dry. The central 

 portion, or " heart," of the plant is dead, and the dying of the rest of 

 the plant is only a matter of days. 



This peculiar reaction to injury is rather characteristic of young 

 cane. It is often due to the work of the borer, but it may result 

 from various other causes. Thus some " dead hearts " are caused by a 

 twisted growth of the inner tissues of the plant, the tissues above 

 such a twist ultimately dying. Other " dead hearts " result from 

 accidents of cultivation. A false step of the mule or the plowman 

 may break the brittle inner tissues near the ground, while the outer 

 portion of the plant, being stronger and more elastic, springs erect 

 after the weight is removed. In a short time the heart dies, and an 

 investigation will show that the inner tissues have been broken 

 cleanly and have turned slightly brown at the point of separation. 



Insect injury other than that of the moth borer also is responsible 

 for " dead hearts." The work of the sugar-cane beetle (Ligyrus) 

 Euetheola rugiceps Le Conte, and other insects produces similar in- 

 jury, the inner portion of the plant being killed before the outer 

 portion. 



