December, '13] WOLCOTT: WEST INDIAN AND DEMERARAN NOTES 453 



duction of an epidemic of the Green Muscardine disease among frog- 

 hoppers. Mr. Uriah assured me, however, that in the one examination 

 he made where spores had been apphed early, at least 95 per cent, of 

 the nymphs in the stool of cane were found dead and covered with 

 the characteristic olive green spore masses of Metarrhizium. 



Most of the planters seem to be convinced of the desirability of 

 using this fungus for the control of the froghopper, and on most of 

 the estates of the island cabinets for groAving the spores were seen. 

 Mr. Connell has already dusted with the spores over 500 acres of 

 cane land at Esperanza estate, and at other larger estates it is planned 

 to dust similar areas. It will be with much interest that the outcome 

 of this most extensive spore dusting during the coming w^t season 

 will be watched. 



In addition to the work with the Green Muscardine, a diligent 

 search has been made for predators and parasites. In the fall of 

 1911, Mr. Urich went to Mexico, where Tomaspis postica Walker, 

 does considerable injury to cane, and he imported from there a Redu- 

 viid bug, Castolus plagiaticollis, which is a very efficient predator 

 on the adult froghoppers. . . . From grass collected in the moist 

 valleys and ravines in the northern part of Trinidad, two Chalcidid 

 parasites have been bred by Mr. P. L. Guppy, Mr. Urich's assistant. 

 One of these is a brilliant vermillion color and the other a light brown. 

 Neither has yet been bred in large numbers; and it is doubtful if they 

 will be of economic importance. That they already occur in the island, 

 and in localities not more than a few miles from cane fields heavily 

 infested with froghoppers, indicates that unless some very successful 

 method of artificial propagation is devised they will never be of much 

 practical value, although interesting from a scientific standpoint. 



On all cane estates in Trinidad, the injury by Castnia licus, the giant 

 moth borer, is most noticeable. Indeed, from what superficial observa- 

 tions I w^as able to make, it seemed to be more common than in Deme- 

 rara. Its numbers are becoming less each year in Demerara, but in 

 Trinidad, the pest is rapidly becoming more a})undant, as Mr. Urich 

 informed me that on onlj^ a few estates were control measures at- 

 tempted. It is impracticable to flood the fields from which cane 

 has recently been cut, no attempt is made to collect the full-grown 

 larvse and pupae from the stools of cane, and the young larvae are not 

 cut out of young cane, but most energetic measures are used for the 

 collection of adults by gangs of boys with butterfly nets. That this 

 method of control is successful if continued over a series of years, 

 is shown by the figures given below, showing the number of adults 

 collected on one estate. 



Castnia Adults Collected on Oxe Estate 

 Year 1909 1910 1911 1912 



No. 182,734 116,707 89,768 52,271 



4 



