DISEASES AND PESTS 85 



the bark is soft, and the sun will make cracks and the 

 sap, which is liked by all of these pests, oozes out in 

 quantities." It also appears that the American palm 

 weevil flies by day as well as by night. 



I have repeatedly used the remains of infested coco- 

 nut trees as bait, removing every trace of insects and 

 leaving the stub to attract others. From the second to 

 the fifth day after the operation there is always a harvest 

 of beetles in the little piles of rubbish deliberately left 

 for them to hide in, when there is not room for all in 

 cracks and holes in the stub itself. Such stubs must 

 not be left, as in a few weeks they are full of larvae 

 and pupae as far down as they have softened enough to 

 be penetrable. 



Vosseler recommends, as bait, mangoes crushed in 

 coco-nut milk and water, and exposed in shallow dishes. 



3. The use of poison. As the holes by which this 

 insect enters the tree are not necessarily visible, and 

 the channels in the tree become of appreciable size only 

 as the larva grows, it is not usually practicable to kill 

 the weevil in any stage by the use of poison. However, 

 when the holes or channels are open, or opened, carbon 

 bisulphide can be introduced and the hole plugged 

 again ; any insects that the vapour can reach will die. 

 This method has been tested, using carbon bisulphide, 

 potassium cyanide, and hydrocyanic acid, against 

 Rhynchophorus and Oryctes, at the Philippine College 

 of Agriculture, without results of practical value. 

 Yosseler advises the use of carbon tetrachloride. 



The larva of Rhynchophorus is said to be regarded 

 as an especially choice morsel by various natives in 

 America, where it is known as the gru-gru worm. The 

 oldest report of these insects, dating back to 1726, 

 emphasizes this usefulness. The larvae are eaten in 

 Africa and Malaya also ; but, so far as I have personal 

 knowledge, they are by no means esteemed a delicacy. 



Rhynchophorus palmarum seems to be a less serious 

 pest than R. ferrugineus. Urich states that " young 

 trees up to four and five years of age are those mostly 



