132 



It is effectively destructive to all kinds of Ants, Land Crabs, 

 burrowing animals, Cacao borers, Book insects, &c, &c, in fact to 

 animal and insect life of all kinds. 



The liquid is generally recommended to be exploded in the holes 

 or burrows, but our experience leads us to conclude that there is 

 a great loss of effectiveness when the material is exploded and that it 

 is better and more effective to apply the liquid on wads of cotton 

 wool, tow. rag, or other material : and cover the holes and allow the gas 

 which the liquid produces to penetrate to all the recesses of the 

 retreats of either insects or animals. 



One of the liquids on examination proves to have the following 

 materials added as the residue after evaporation was composed 

 of 62 per cent, of napthalene and 38 per cent, of sulphur 

 These substances readily dissolve in Carbon- bi-sulphide, but it has 

 not been found that they add anything to the effectiveness of Carbon - 

 bi-sulphide used alone. 



648.-THRIPS AND BLACK BLIGHT. 



The following report by Mr. H. A. Ballou, the Entomologist 

 under the Imperial Department of Agriculture for the West Indies, 

 gives considerable information as to the attacks of Thrips and black 

 blight in Grenada. In Trinidad so far these infections have not been 

 of great importance. 



Thrips give considerable trouble in Hot House culture in tempe- 

 rate climates ; but are generally very successfully kept down by 

 syringing, and by maintaining an abundance of moist air. To the 

 greater humidity of the climate of Trinidad, is probably due the 

 general freedom from attack which our planters experience. 



Barbados, 



17th May, 1904- 



" Sir, — I have the honour to present herewith a report on my 

 visit to Grenada from May 10th to 13th inclusive. 



2. During this visit, my attention was given to an investigation 

 of the " Thrips " of Cacao and " Black Blight." 



3. Thrips of Cacao (Physopvs rubrocinctus). — This pest has been 

 known in Grenada since 1898 when it attracted the attention of the 

 Cacao Planters, and specimens were sent to the British Museum for 

 identification. In November, 181)9, Mr. Broadway, Curator of the 

 Botanic Station, sent a letter to this office referring to mention of it 

 in the Eeport of the Grenada Botanic Station, for 1898 and recording 

 its appearance at Good Hope Estate. Since that time, there have been 

 several outbreaks of this pest in Grenada, and it has also appeared in 

 other islands. 



4. The following is a list of the published references to " Thrips " 

 on cacao at Grenada most of which contain also recommendations as 

 to the treatment of the disease or the use of spraying apparatus 

 for applying insecticides : — 



(1.) West Indian Bulletin, Vol. II, pp. 176, 181 & 288. 

 (2.) Agricultural News, Vol. II, pp. 56, 66, 88 and 134; 

 Vol. Ill, Page 10. 



