448 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



I wish to emphasize the fact that Diatrcea is NOT controlled in 

 Demerara, by the two egg parasites, Trichogramma and Telenomus, 

 the larval parasites, the cutting out of dead hearts, the collecting of 

 nonparasitized egg masses, clean cultivation, the burning or not 

 burning of trash, all combined. 



Mr. J. J. Quelch, the Entomologi.st for the planters, tells me that the 

 one measure that can be adopted which will in part make up for the 

 lack in Demerara of a season when no partially grown or large cane 

 is present as a source of re-infestation of the young cane, is the simul- 

 taneous planting of enormous blocks of cane. It is the indiscriminate 

 scattering of the fields of all ages of cane on an estate that makes 

 possible the rapid and easy infestation of young cane. Diatrcea moths 

 are not long distance flyers and when all young cane is in a large 

 block away from the older cane, it will not be so readily infested. 

 This is undoubtedly a very ambitious plan of campaign against the 

 smaller moth borer, but the amount and seriousness of the injury 

 and the comparative ineffectiveness of the methods of control, now 

 used, make radical measures necessary. 



The only other serious pest of cane in Demerara is the giant moth 

 borer, Castnia licus Fabr. Several years ago the injury caused by 

 this pest was very great, but the systematic warfare commenced 

 against it has lessened its numbers to such an extent that its depre- 

 dations are now of somewhat minor importance. The eggs of the 

 moth are deposited in the earth or in trash on the ground. The young 

 larva enters the cane at the surface of the ground and burrows down 

 into the root and also up into the stalk. The larvae grow to be four 

 inches or more in length and half an inch in diameter. It may well 

 be imagined how serious is the injury that one larva does to a stalk 

 of cane. When the cane is young one individual will often kill several 

 stalks and one can readily see the injury in the field even before the 

 cane is cut. Older cane, however, is not killed by Castnia, for the 

 larva eats only the sweet pithy inside of the lower portions of the 

 cane, and the growth at the tip is not appreciably checked. It is 

 only when the cane is cut that one can accurately determine the 

 extent of the injury, as then the large holes in the stubble are most 

 noticeable, or by watching the cane in the cane cars the amount of 

 infestation is easily estimated. 



Despite the large amount of injury the giant moth borer is capable 

 of producing, it is an indication of poor estate management if it is 

 allowed to cause serious trouble, as there are several entirely practical 

 measures of control. A measure that naturally suggests itself is the 

 capture of the adults. These big day-flying moths are a common sight 

 in the cane fields, being most abundant on bright days between ten 



