xviii Remedial Measures and Insecticides, 



and by grafting on to this hardy stock they have been able to 

 immunise their more delicate and valuable varieties. In Ceylon 

 we have the strongest evidence that certain varieties of the tea 

 plant (especially the Assam indigenous stock) are most markedly 

 free from injury by the so-called 'mosquito blight' {Helopeltis). 

 In any serious epidemic that may threaten the profitable cultivation 

 of an economic plant, we should at once be on the look-out for 

 any accidental varieties or strains that may prove resistant to that 

 particular disease. In cases where the hardier stock is not other- 

 wise so profitable as the more delicate variety, by grafting upon 

 it a more valuable scion the latter may sometimes be rendered 

 equally immune. 



Curative Measures. 



Where preventive measures have failed, as — even with the 

 greatest care — must often happen, recourse must be had to curative 

 measures. 



In no single connexion can the old proverb, ' A stitch in time 

 saves nine,' be more aptly applied than in dealing with insect 

 pests. In this case the 'stitch in time' is more likely to save 

 ninety, or nine hundred, or nine thousand ! 



If a pest is to be eradicated, immediate treatment is the most 

 important part of the process. 



And the first step towards treatment should, when possible, 

 be the isolation of the infected area. All ordinary work amongst 

 the affected trees should be deferred until after treatment. The 

 young larvae of scale-insects are very minute and active, and one 

 of the most fertile sources of their distribution is by means of 

 clothing. The rough 'cumblies' used by the estate coolies are 

 particularly well adapted for their transport. 



Another important point is that the treatment should be 

 applied on the spot. If the infected branches are cut down and 

 carried off to some other part to be burned, they may be shedding 

 the germs of the disease all along the way. 



It is difficult to lay down hard-and-fast rules for action, so 

 much depends upon circumstances, e.g. the nature of the particular 

 pest, its extent, the nature and value of the plant attacked, &c., &c. 

 But, for the sake of example, we will suppose a case in which 

 three or four tea bushes are found to be infested by some scale- 

 insect that is considered to be a dangerous pest. First dig a 

 fair-sized hole in the midst of the affected clump, and place in it 

 some dry grass and sticks as foundations for a fire. Fill two or 



