30 FROGHOPPER Bl.lGUT OP SUGAR-CANE 



SECTioN^ rxi. 



THE HISTORY OF THE BLIGHT IN TRINIDAD. 



In order to get a proper understanding of a disease that varies 

 greatly in intensity in difl'erent years and localities it is important to 

 have an accurate history of the post attacks. From such a record it may 

 be possible to determine the cause of the prevalence of the disease, or, at 

 least, suggested causes may be eliminated. 



In the present case the records ware originally collected to test the 

 suggestion that the blight had arisen in the past fifteen years owing to 

 the introduction of the mongoose, which question will be found 

 discussed on page 87. They have also been used to trace a relation 

 between the distribution of the rainfall and the extent of the blight. 

 {See Williams 1919 E. and p. 96 of present report). 



It has been difficult to get a historj' of the blight as few estates have 

 kept accurate records, and little notice has been attracted except in the 

 years of severe injury. The published literatui-e has been searched and 

 also the unpublished monthly reports of the Officers of the Board of 

 Agriculture. Much information for the year 1912 was obtained from the 

 replies to a circular sent out by the Department of Agriculture in that 

 year, and for the year 1917 from the replies to a somewhat similar 

 circular that I sent to the chief estates. 



The dates given are the year in which the crops were growing, not 

 the year in which they were cut. 



1862. 



Cruger, writing in 1863 (published 1892) says that in the previous 

 year a blight attacked the sugar-canes. There was "alarming damage" 

 about September or October, but the canes recovered by the end of the 

 year. He also notes that the season was much drier than usual. There 

 is no mention of any insect that could be identified as the froghopper, 

 but the time of out-break of the disease and later recovery suggest 

 identity with the present blight. 



1869. 



According to Urich (191o C. p. 7) the local newspaper '• Trinidad 

 Chronicle" for 5tli October 1869 says that "Canes in the ('haguanas 

 district are attacked by a peculiar disease \evy like a blight." 



Once more there is no mention of an insect, but the date corresponds 

 to the time of greatest froghopper infestation. 



1878. 



In this year there seems once more to have been a severe outbreak 

 of disease in the canes. L. A. A. de Verteuil writing to H. Prestoe 

 (Government Botanist) on 17th November, 1878 says "The blight of 

 which they have been talking for the last several years has kept one 

 somewhat anxious. The blight begins to show itself in September,, 

 becomes worse during the blooming or arrowing season — in October and 

 November — and then not only makes no further progress, but some of 

 the canes which evidentlj- had become blighted recover, and new sj^routs 

 make their appearance." (Hai-t 1894). 



On 81st March 1879 Mr. I restoe wrote in a letter that the disease 

 was due to rotten roots and that " every cane stool that I examined in 

 one field was infested with the fungus." (Hart 1893). 



