222 TRINIDAD AND TOBAGO BULLETIN, [XIX. 4.. 



The preliminary observations showed very little beneficial results 

 from the spraying with the two former mixtures. Lime sulphur was 

 effective where actual contact with the insects was obtained, but crude 

 oil emulsion appeared to be the most effective from all points of view. 

 The oil laid somewhat thickly on the trunk and leaves but no injury was 

 noticed either to the leaves or bark. 



The flowers with which the emulsion came in contact were however 

 injured, and it would be necessary to spray with such an emulsion when 

 the trees were not in flower. An emulsion made in more dilute 

 proportions might also be tried. 



B esides being the most effective spray ^of the four experimented with 

 crude oil emulsion was also found to be much the cheapest. Lime 

 sulphur is worthy of further trials provided sulphur can be obtained at a 

 cheaper rate than it was possible to purchase it at in Grenada. 



Whilst, as Mr. Ballou points out, neither of the sprays has the power 

 of penetration, it seems to me that the crude oil emulsion may also act 

 as a preventative as well as a cure by making the surface of the trees 

 distasteful to the insects. This work, however, is still in such an early 

 experimental stage that it would be presumption on my part to offer any 

 definite opinion. In Trinidad mealy bugs, from their scarcity, may be 

 presumed to be kept in check by fungus parasites by virtue of our more 

 humid conditions. 



Termites. 



Another pest not as serious as the former but all the same one 

 which accounts for the loss of a fair number of trees annually in certain 

 parts of the island, is the large termite {Kalotermes Ballouii). This 

 large termite or wood ant enters old wounds and tunnels through the 

 wood of the tree sometimes for a distance of four or five feet. The 

 occurrence of this pest in a tree is usually not observed till the whole 

 tree or branch is broken down. It can however be discovered earlier if 

 an examination of old decayed wounds be made. The point of a knife 

 dug into the rotten wood will as a rule expose a few of the insects if 

 they are present. 



The old adage, prevention is better than cure, is the best to apply to 

 this pest, and if all wounds caused by pruning be treated with an 

 antiseptic and even all old treated wounds inspected and re-treated 

 occasionally if necessary, little trouble from the pest should be 

 experienced. Whilst speaking of antiseptics I may say that paint and 

 tar have been and are still largely used in Grenada for the treatment of 

 wounds, but crude oil is now becoming the most popular remedy and I 

 must say that from personal observations it is apparently most 

 efficacious. 



Other Pests. 



There are a number of other pests of more or less minor importance 

 and with which you are familiar, so I will not treat them in detail. 



Bird vine is fairly troublesome, but it does not appear to be such a 

 strong or rapidly-growing species as the one with which you are so 

 familiar in Trinidad and Tobago. 



