It is probable that the eggs of the bark borer are laid 

 only in dead or dying portions of the trees, but it is also 

 likely that the grubs, by their feeding, very often increase 

 the amount of dead wood and hasten the death of the tree. 



Bark borers can often be located by the dead and 

 shrunken patches of bark. They can be dug out with a 

 knife and the wound thoroughly cleaned and tarred, or they 

 may be killed by probing with a wire, or by the use of car- 

 bon bisulphide, injected into the tunnels of the borers. 



A small weevil of the 

 genus Cryptorhynchus (Fig. 

 90) has been reported as a 

 borer in the stems of orange 

 trees in Grenada. This insect 

 can hardly be called a pest, 

 since its occurrence is compara- 

 tively rare. In the event of 

 large cultivations of oranges 

 being established, however, the 

 possibility of a very rapid 

 increase in the numbers of the 

 borer should be kept in mind. 



Fig. 90. Orange bark weevil. 

 (Imperial Dept. Agric.) 



THE RUST MITE (Phytoptus ol&ivorus, Ashmead). Acarina. 



The rust mite is not of very common occurrence in 

 the West Indies. It is a small mite similar to the leaf- 

 blister mite of cotton. It feeds on the skin of limes 

 lemons and oranges, producing in the case of the latter a 

 russet appearance, and in the case of limes and lemons a 

 silvery appearance of the skin. Dry flowers of sulphur, 

 used pure or with equal amounts of lime, is the remedy 

 employed in Florida when it becomes necessary to control 

 this mite by artificial means. This insecticide would 

 probably be found satisfactory also in the West Indies ; 

 it is applied after rain, or in the early morning while the 

 foliage is still wet, being broadcasted from the hand. 



Bengal beans have been much used for the control of 

 scale insects and the general improvement of lime trees in 

 Montserrat. The beans were planted, about four to each 

 tree, and allowed to grow and completely cover the trees. 

 The accompanying illustration (Fig. 91) shows the 

 appearance of a field covered in this manner. 



