94 



TBINIDAD AND TOBAGO BULLETIN. [XVIIL 2. 



secured in the bamboo rod and that it does not turn when the fittings 

 are being screwed up. The length of a rod should not exceed 12 feet 

 for average spraying on cacao estates. Longer rods are very fatiguing to 

 the labourer and when the trees are very tall it is better to use ladders as 

 is sometimes done for pruning or climb the trees. 



Stopcocks are very important, a simple and reliable one is repre- 

 sented in fig. 8. The use of a stopcock saves spraying mixture when 

 moving from tree to tree. 



An angle nozzle (fig. 9) is the best kind for directing the spray to 

 the underside of leaves where most of the thrips occur. The hole in 

 the disc should not exceed -^^ inch in diameter ; after long use the 

 hole is apt to wear larger, when a new disc must be substituted. 



Fig. 15 represents a useful pair of pliers to have in connection with 

 spraying ; a shifting spanner is also useful. 



SPRAYING MIXTURES. 

 Thrips are killed by a contact insecticide, which means that only 

 those insects will be killed which are wetted by the liquid. 

 Sometimes it is advisable to use a combined spray mixture which will 

 act as a fungicide i.e. a fungus killer and an insecticide i.e. an insect 

 killer as well ; in connection with cacao and thrips a mixture of Bordeaux 

 and Blackleaf 40 or Kicotine sulphate has always given very good 

 results. Bordeaux mixture kills moss on the trees and prevents black 

 rot and canker, and Blackleaf 40 kills thrips and other insects. 



Bordeaux Mixture. 

 To make 50 gallons Bordeaux mixture the following ingredients are 

 required: — (see fig. 16). 



rig. 16. 



Fig l(i.— Method of niixiiij; Bordeaux. Redrawn from Korer. 

 Copper sulphate or bluestone— 5 pounds ; 

 Temper lime, in lumps not in powder — 5 pounds; 

 Watir — 40 Imperial gallons or 50 American gallons. 



