454 JOURNAL OF ECONOMIC ENTOMOLOGY [Vol. 6 



Approximately the same number of boys was employed in the collec- 

 tion each year and the figures are therefore comparable. If the 

 collecting of adults for four years produced a decrease of over 70 per 

 cent, in the numbers of the pest, it may be more easily realized how 

 much better Castnia is kept under control in Demerara where additional 

 measures are used. 



Although cane infested with the smaller moth borer is common in 

 Trinidad, the injury by this species is not serious as compared with 

 that produced by the froghopper. Although much more common 

 than Castnia, the total amount of injury produced by Diatrcea is 

 not so great. Nothing in the way of control is attempted on any 

 estate. None of the managers have sufficiently realized the loss 

 caused by Diatrcea to seriously attempt to control it. This is not 

 particularly surprising as the Diatrcea larvae are abundant only during 

 the beginning of the rainy season, May and June, but after this they 

 are comparatively scarce. Ordinarily the smaller moth borer does 

 not cause much dead heart, as the larvse do not become abundant 

 untii after the cane has advanced beyond the earlier stages of growth. 

 In that portion of the cane stalk between three inches and a foot from 

 the ground occurs about 90 per cent, of all the injury that one sees 

 on cane brought to the mill. This was especially noticeable at the 

 Usine Ste. Madeleine. Whether anj^ other factors than rainfall 

 and abundance of parasites enter into this sudden appearance and 

 practical disappearance of Diatrcea has not yet been worked out. 

 The egg parasite Trichogramma minutum (pretiosa) Riley, is quite 

 common and the brilliantly marked braconid parasites of the larvae 

 are abundant in the fields. Three of them were seen hovering over 

 the cane on the cane carriers of the Usine. They were not feeding 

 on the juice from the cut ends, but rather were examining the Dia- 

 trcea holes. 



Among the more important minor pests of cane in Trinidad are the 

 weevil stalk borer, Metamasius hemipterus Linn., var. decoloratus 

 Gyllh., the "gru-gru" worm, Ryncophorus palmarum Linn., and 

 the sugar-cane mealy bug, Pseudococcus calceolarice Mask. The 

 latter is moderately abundant on most cane, but appears to do but 

 little serious injury. It is attacked by the larva of a predaceous 

 lady beetle, which is present where the mealy bugs are most abundant. 

 The injury by the "gru-gru" worm is mostly confined to seed-cane 

 that has not been properly treated with Bordeaux mixture. The 

 weevil stalk borer is quite common but never so abundant as to do 

 serious damage. In some of the cane brought in to the Orange Grove 

 mill by coolie cane farmers, a few stalks were noticed which had 

 been almost entirely destroyed by termites. While looking over 



