f>2 H. A. BALLOU — NOTES ON INSECT PESTS IN ANTIGUA. 



opinion, prevent the development of the lime industry in Antigua, as it ought to 

 be a fairly easy pest to control. Within a very short time from the beginning 

 of the attack the grub injures the branch in which it is to complete its develop- 

 ment to such an extent as to make the injury very conspicuous. First of all the 

 leaves wilt, then discolour and dry up ; about this time the branch breaks at the 

 point of girdling and usually hangs in the tree, forming a very conspicuous notice 

 of the presence of the beetle (Plate VIII). 



The remedy to be employed is therefore obvious. Any dying branch on 

 which the leaves are curling up or turning yellow should be carefully examined 

 for the presence of the borer, and if the grub can be found it may easily be dug 

 out or the branch cut off sufficiently far back toward the tree to ensure the 

 removal of the grub. It is more likely that the attacked branches will most often 

 be detected after the breaking down has occurred and then the point at which the 

 branch should be cut is clearly indicated. When the branch has broken the 

 grub will always be found in that part of it beyond (or outside of) the break. 

 If all these broken branches in which the grubs occur can be collected and 

 burned, say at intervals of one month, it ought to be possible so far to reduce 

 the numbers of this insect that it would no longer be a pest. 



The loss of the attacked branches in the first instance, is, of course, an 

 important item from the lime-growers point of view ; but if this system of 

 collecting is carefully carried out, there will probably be very little infested 

 material to collect after the first two or three times, because the destruction of all 

 the developing grubs over a period of three or four months will very largely 

 preclude the development of further broods of the insect. 



The lime twig borer is different in appearance and in habit from the lime 

 bark borer {Leptostylus praemorsus), which has at times been plentiful in 

 Dominica and is known to occur in several other islands. The latter lives entirely 

 under the bark, the attack generally beginning in the vicinity of a patch of dead 

 bark caused by bad pruning or other injury. Its tunnels sometimes extend into 

 living tissue and very rarely enter the centre of the stem. The attacks of this 

 insect usually occur on the larger branches and the main stem, often near the 

 ground-level where the plant has been injured by hoe or cutlass. 



The attacks of the twig borer, on the other hand, always occur higher up in 

 the tree, among the smaller branches and twigs. The branches which are 

 girdled and break off are usually not larger than one inch in diameter, generally 

 g or | of an inch. Occasionally, however, branches larger than one inch have 

 been found girdled ; some of them were broken off (Plate VIII), while in others, 

 either the injury was sufficient to kill the branch above without its breaking off 

 at the point of attack, or the attack has been stopped and the tunnel filled with 

 gum. It is not possible to say exactly what arrested the progress of the grub in 

 forming these tunnels, but it may be that the amount of gum secreted by the 

 plant was sufficient to cause the death of the insect before the injury was exten- 

 sive enough to cause the death of the branch. 



In several localities the orange red scale or California red scale, Chrysomphalus 

 (Aspidiotus) aurantii, was observed in such abundance and under such conditions 

 that it appeared to be doing very serious damage. Young limes two or three 

 years old, are being killed by it (PL IX, fig. 1) and in another older lot of trees, 



