Remedial Measures and Insecticides. xix 



three buckets with one of the insecticide washes described below. 

 Prune back the branches one by one ; immerse each branch com- 

 pletely in the insecticide and throw it into the hole, until nothing 

 but the bare framework of the tree is left. Sweep all fallen leaves 

 and rubbish from beneath the trees into the hole. Next, paint over 

 the bare stems with the same insecticide, using a large paint brush 

 and taking great care to saturate the entire surface down to the 

 ground. Then set fire to the heap of prunings, and cover up the 

 remains with earth. To kill off possible stragglers, the unpruned 

 trees immediately surrounding the affected patch should be tho- 

 roughly sprayed with the mixture. If carried out in time, these 

 measures will probably stamp out the pest ; but a careful watch 

 should be kept for any fresh outbreak. 



The above treatment is suitable only for such plants as may 

 be cut down without permanent injury. We may now consider 

 the case of some larger tree to which this method would be in- 

 applicable — say an orange or cocoa tree. In this case the gas 

 treatment is the most suitable. The application should be 

 repeated after an interval of about a fortnight, to ensure the death 

 of larvae subsequently hatched from eggs that may have survived 

 the first operation. Full directions for gas treatment are given 

 below. i^See pp. xxvii — xxxi.) 



In other cases a combination of these two methods might be 

 adopted. If two or three coffee trees should require treatment, all 

 superfluous branches might be pruned, dipped, and burned, and 

 the standing trees fumigated with gas. Modifications of the treat- 

 ment will be required to suit particular cases. 



When a serious pest has once firmly and widely established 

 itself, little hope can be entertained of exterminating it, though 

 much may still be done to keep it in check. 



Where trees are large and more or less detached, as in orange 

 groves, and the crop a valuable one, the gas treatment is again the 

 most satisfactory one. But where the cultivation is denser, and 

 the crop not so concentrated, spraying is found to be more 

 practicable. 



The choice of the insecticide must be regulated by the nature 

 of the crop. Arsenious compounds cannot be safely applied to 

 food crops — such as fruit and vegetables — during the cropping 

 season. And they can on no account be recommended for such 

 a product as tea, unless employed exclusively after pruning. For, 

 however minute may be the actual amount of active poison 



