BEETLE PEST ON THE GAPIS ESTATE. 0)1 



From the above it is evident that thei'e is only one part of 

 its life when it does any harm to the planter, that is when 

 in the beetle stage ; and that it is also only during the same 

 stage when it can be attacked with any prospect of destroying it 

 in useful numbers. To do this when they are on the bushes 

 there would appear to be only two methods of procedure ; hand 

 picking and poisoning. The latter I venture to think would be 

 found both expensive and ineffectual. It is one of their habits 

 to drop off the trees as soon as disturbed, so that they would 

 escape the spray in the case of an oil emulsion and if poisonous 

 arsenical powders were used the rain here is too heavy and 

 frequent to permit them to remain on the foliage for a sufficient 

 time to have any practical effects on leaf feeding insects. Hand 

 picking, as inaugerated by Sir Graeme Elphinstone, therefore 

 appears to be the only method of destroying these pests which 

 it is possible to apply on an estate. 



The fact that the female is some time before she begins 

 to lay, and also that she lays her eggs singly, makes it probable 

 that if picking is carried on systematically and uninterruptedly 

 it will finally eradicate the pest, or at any rate so keep down the 

 numbers of the insect that its presence will do little harm to the 

 crop. 



There is one point which might be worth while to test 

 experimentally. It is the cultivation amongst the coffee of some 

 of the plants of which the pest is very fond to serve as bates, 

 and so lessen both the damage done to the coffee and also the 

 trouble of catching the insects. There are some few plants 

 which the beetle appears to much prefer to coffee, and it is these 

 which I would propose to either plant or let grow in the fields. 

 One of them is a small sized tree with blackish green, narrow 

 leaves which is very common about Gapis. The wild silk cotton 

 is another and, according to Mr. Mackay, the "dadap" is a third. 

 In all cases they should not be allowed to grow higher than the 

 reach of the beetle collectors, and should be visited at frequent 

 intervals. 



The causes which have operated to spread the pest on the 

 estate are easily understood when its life history is studied. 

 The land around Padang Rengas for many years past has 

 been cleared and more or less cultivated by the villagers and 

 thus made suitable to the requirements of the grub, while there 

 have been a plentiful supply of both wild and cultivated food 

 plants for the beetle to feed on. The place was therefore just 

 what was required to favour the multiplication oi the pest. 

 Then, I understand that for some considerable time after it was 



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