14 FROGHOPPER BIJGHT OF SUGAR-CANE. 



Gough iu 1910 (1911 C.p. 10 & 23) gave figures of the cosb of produc- 

 tion of cane per ton on healthy and blighted fields. These were — 



Healthy field ... ... 11.09 per ton. 



Shghtly bhghted ... ^1.01-^1.49 per ton. 



Badly kighted ... ftl.iDS-eS.SO 



This last section obviously does not include fields completely 

 destroj'ed, as in these the whole expenditure is a dead loss. It is 

 scarcely necessary to add that while the relative value of the figures 

 remains, it is no longer possible to produce canes at the cost here given. 



Urich (191B C. p. 9) estimates the average damage from 1907 to 1912 

 as 10 per cent, of the crop, which at the then ruling prices was equal to 

 a loss of about i'55,000 per annum. 



In 1916-17, a year almost free from blight, the export of sugar from 

 the island was about 71,000 tons. In the. following year it had fallen to 

 46,000 tons. Nearly 50 per cent, of this drop was due to disease of 

 which the froghopper was the prime cause. The loss for that year was 

 therefore about 12,000 tons of sugar worth ^.300,000 at the price then 

 prevailing. 



Further details of the loss will be found in Section III (p. W) which 

 deals with the history of the disease in Trinidad, but it will be i-een 

 firom the figures already given that the planters of the island are faced 

 with a disease which takes a considerable toll of their profits each year 

 and which has moreover shown little sign of diminishing in intensity 

 in recent years. 



The damage during 1917 was unsurpassed by that in any year with 

 the possible exception of 1912, and many estates were only saved from 

 a serious loss on the year's working by the higli price they were able to 

 obtain for the sugar produced. Should prices again fall to anything in 

 the neighbourhood of the pre-war figures, damage such as that in 1917 

 would make it almost impossible for smaller companies to carry on. 



INVESTIGATIONS UP TO 1916. 



In the course of my work and in the preparation of the following 

 report I have made free use of the results of previous investigations, all 

 of which will be acknowledged in their place. It might be convenient 

 here, however, to summarise the work that had been done and the 

 position in which I found it in 1916. 



The earliest mention of damage at all resembling the present 

 " Blight " is in a report dated 26th January 1868 by H. Cruger (see 

 Bibliography at end, Cruger 1892). He describes the condition of the 

 cane as being " alarming a few months ago " but says that since then 

 " the canes have recovered nearly everywhere." He describes several 

 insects attacking the canes but none of these could be identified with 

 certainty as the froghopper. He mentions a " louse-like" insect on the 

 roots, but the absence of any reference to the conspicuous froth makes 

 it doubtful that this was the froghopper. 



C. E. A. Francis made in 1878 a " Chemical Analysis of Blighted 

 Sugar Cane and the soil in which they were grown" (Francis 1881). 

 He found the cane ash deficient in silica and the soil deficient in lime as 

 compared with several Antigua soils. Once more there is no definite 

 indication of the cause of the blight. 



