RUBBER PLANTING 181 



roots of entirely healthy trees. The insects then rapidly 

 proceed to eat out the interior of the wood. Termes 

 Gestroi is a pest which requires to be seriously taken in 

 hand at its very first appearance. By digging a shallow 

 trench round an affected tree it is often possible to 

 locate the position of the termites' nest, because the 

 insects quickly build covered ways across the bottom of 

 the trench in order to obtain access to their food supply, 

 and by following these up the direction of the nest can 

 be determined. The best means of exterminating the 

 white ants is by pumping into their nests the fumes 

 of sulphur and white arsenic, generated by heating 

 these substances over burning charcoal in a special 

 apparatus. The channels excavated in the affected tree 

 may be similarly fumigated, but if the damage has pro- 

 ceeded far it is simpler and more effective to cut down 

 the whole tree and burn it. 



In its early stages of growth Hevea is susceptible to 

 the attacks of a somewhat larger variety of insect pests. 

 Young plants in nurseries, and those which have recently 

 been planted out in clearings, are subject to damage 

 from cockchafer grubs, cutworms and similar sub- 

 terranean creatures which gnaw the roots. These may 

 be got rid of to some extent, at least in nurseries, by 

 treating the soil with kainit or with " vapourite," a 

 preparation sold for the purpose. 



One animal against which the presence of latex is 

 no protection is a slug Mariaella Dussumieri which 

 actually drinks the latex, and appears to thrive upon a 



