1922.\ CACAO CULTIVATION IN GRENADA. 221 



remedy is therefore to put the soil in proper condition but as this cannot 

 be done quickly it is necessary to spray in the case of a severe attack in 

 which immediate relief is required. 



The best spray for the purpose and the one most generally employed 

 is Nicotine sulphate (Black Leaf 40), used (on the recommendation of 

 Mr. Urich, Entomologist of the Trinidad Department of Agriculture, who 

 visited Grenada a few years ago to advise on Thrips) at the rate of six 

 ounces to fifty gallons. It -is usually applied in combination with 

 Bordeaux mixture made on the 5.5.50 formula. 



When the trees are in a healthy condition it is doubtful whether ever 

 thrips assume epidemic form, in fact it was once stated by Mr. Ballou, 

 Entomologist of the Imperial Department of Agriculture that thrips 

 might be regarded as a friend of the planter in that it showed him that 

 something was wrong with his cultivation. 



In short then the advice for treatment of an epidemic of thrips is to 

 improve the cultivation and spray with a mixture of nicotine sulphate. 

 As a preventative measure the advice is to keep the cultivation to a high 

 standard. Unless a high standard of cultivation is maintained under the 

 no-shade conditions, the trees are more susceptible to attacks of thrips 

 for the reasons stated when dealing with permanent shade. 



Mealy Bug and Black Ants. 



A pest which is- causing considerable trouble in the cacao fields of 

 Grenada at the present time is mealy bug, which, in combination with 

 the black ant, is commonly found on estates and is no doubt the cause of 

 considerable loss in crop. 



In bad attacks the undersides of the leaves are thickly covered with 

 the white mealy bugs as are also the flower cushions, flowers and pods. 

 The mealy bugs form an attraction for the black ants which feed on their 

 excretions. Large colonies of both pests are found clustering among the 

 cushions of infested trees. They make their way into holes and 

 crevices caused by pruning and the gathering of pods and almost 

 certainly aggravate such injuries. 



A short time ago a visit was paid by the Entomologist of the 

 Imperial Department of Agriculture to specially investigate this pest, 

 and we visited together plantations in all parts of the island. After his 

 visit a set of experiments were commenced by his suggestion in three 

 different parbs of the island to tast the value of various mixtures 

 for spraying purposes. As a preliminary measure to spraying he 

 recommended the thorough cleaning up of the trees by close pruning of 

 all old stumps of branches and dead material and the painting with crude 

 oil of the cut surfaces. 



The spraying materials recommended for trial were : — 



Bordeaux Nicotine 5.5.50.6. 



Bordeaux and arsenate of lead 5.5.50.2. 



Lime sulphur : Stock solution 4 lb. lime, 8 lb. sulphur, 9 gallona 

 water, boiled together for 45 minutes and diluted 1 to 14, 



Crude oil emulsion : 1 lb. soap, 1 gallon crude oil to 10 gallons of 

 water. 



