42 BULLETIN 746, U. S. DEPARTMENT OP AGRICULTURE. 



(Hcnicospilus) antankarus Saussure, Apanteles simpllcis Viereck, and 

 a tachinid fly from Mauritius. Jarvis (83) states that Diatraea sac- 

 charalis " appears to be under effective natural control in Queens- 

 land," while Mr. Frederick Muir has told the writers that this is the 

 case in the Philippine Islands also. 



REPRESSION. 



EXPERIMENTS AND OBSERVATIONS IN ARTIFICIAL CONTROL. 



DESTRUCTION OF SCRAPS OF CANE LEFT AFTER GRINDING. 



One of the chief places of hibernation of the moth borer is in 

 scraps of cane left about the plantation. The wise manager will 

 therefore collect such scraps as soon as possible after the grinding 

 season and destroy them. On a plantation on which many scraps 

 had been left about the mill and the derricks from one season to the 

 next the infestation was practically 100 per cent over the whole 

 plantation. 



After the scraps are collected they may be disposed of by a very 

 thorough burning with oil or some dry material. Throwing the 

 scraps into a lake or other body of water is not to be recommended, as 

 some of the moths may emerge from the floating stalks or from those 

 which are washed ashore. Passing the scraps between the rollers of 

 the mill has been recommended, but this would hardly be practicable 

 on the ordinary plantation. 



CUTTING OUT " DEAD HEARTS." 



The dead plants, or " dead hearts," which follow the work of the 

 moth borer in the spring, contain for a few weeks the larvae which 

 have killed them. A familiar recommendation has been to cut out 

 these dead plants and burn them, care being taken to cut to or even 

 below the surface of the ground so as to secure the larva?. 



The writers had an opportunity of observing this work in prog- 

 ress on a large scale at the State penitentiary farm at Angola, La., in 

 the spring of 1917. The cutting of the " dead hearts " was being done 

 very efficiently by convicts. They collected the dead plants in bags 

 and burned them on the headlands. It was the opinion among the 

 foremen that the " dead hearts " should be cut out of each field three 

 times during the early growing season. One man was said to cover 

 4 acres per day. 



The writers made a point of revisiting the penitentiary farm in 

 the fall to ascertain the results of the work. It was found that the 

 average infestation of the whole plantation was 31.5 per cent, which 

 for 1917 was not extraordinarily low. Around Port Allen, La., for 

 instance, the average infestation was 30.7 per cent, and the " dead 



