Notes on the Society's Work in 1897-1918. xxvii 



where the disease was due to Diplodia cacaoicola. On estates in this county 

 the progress of the disease -was exceptionally rapid ; fields which one 

 week looked green and full of promise in the next looked as if they had 

 been ravaged with tire. One plantation the crops of which had been 

 conservatively estimated at 2.1 tons of sugar per acre made only 9 ton. 

 This outbreak compelled the owner of the estate to abandon the cultiva- 

 tion of the Bourbon cane and to plant new seedling varieties in its stead. 



The following table gives some idea of the extent of the changes in 

 the varieties of cane cultivated which the liability of the Bourbon cane 

 to attacks of rind and root fungus has occasioned : — 



Seedling 

 Varieties. 



1897 

 1902 

 1907 

 1912 

 1917 

 1918 



(about) 600 

 4,100 

 33,665 

 18,250 

 67,680 

 69,475 



*Mixed in part with other varieties. 



The sugar planters during the 21 years under review have had diffi- 

 culties other than droughts and fungoid diseases to contend with. Insect 

 pests have been rife and have done great injury to their crops. During 

 the whole of the period the smaller moth-borer (Diatraea Saccharalis F.) 

 has always been in evidence and has greatly reduced the yield of the 

 sugar estates. Its inconspicuous nature, however, has apparently prevented 

 the majority of sugar estate managers and especially their field-assistants 

 from realizing what a dangerous pest it is and the immensity of the losses 

 it occasions. 



In 1899 a new sugar-cane pest was reported as occurring on 

 certain of the sugar plantations at Nickerie, Surinam. In the 

 course of a few years it spread to British Guiana and from the 

 forests behind the empoldered areas to the fields of sugar-cane 

 and was then named the great moth-borer (Castnia liens. Drury). 

 Its outbreak proved to be a blessing in disguise. It forcibly drew 

 attention to the error which had been made in 1903 in depriving 

 the colony of the services of a highly trained biologist at the time of the 

 retirement of Dr. Evans from the Curatorship of the Museum. Two 

 firms, Messrs. Booker Bros., McConnell & Co., and Curtis, Campbell 

 & Co., combined together and induced Mr. J. J. Quelch to return to the 

 colony to make a practical scientific study of the pest. The Government 



