Ill 



DISEASES AND PESTS 



97 



the insects on the treated trees had been killed. It has 

 since reappeared. 



The larvae feed only at night. At daybreak they 

 retire into a tough nest, shaped like a narrow bag, from 

 30 to 60 cm. in length, in which 700 or more often 

 crowd together. The nest is made with the help of the 

 pinnae, and where their tips meet, at the lower end, is 

 slightly open. As many as four nests are sometimes 

 found in one tree. The larvae are 5 to 10 cm. long. 

 They can entirely strip a bearing tree of its foliage in a 

 few nights, and give it such a check that under con- 

 ditions otherwise most favourable two or three crops 

 are lost ; " And it is no rare occurrence that a tree dies 

 outright or becomes so weak that it cannot resist fungoid 

 and other diseases, and gradually perishes." 



The chrysalis stage lasts twelve to sixteen days. 

 The larva of an apparently dipterous insect is parasitic 

 on the chrysalis, and helps to hold the pest in check. 

 The simplest and easiest way to fight this pest is by 

 cutting down and burning the nests ; but watchfulness 

 and diligence are necessary if this method is to be really 

 effective. Brassolis has also been found on the royal 

 palm, and some other trees of the same family. 



A related species, Brassolis sophorae, has been 

 known in Trinidad since 1892. It is scattered over 

 the whole of that island, and while not common, is 

 becoming more so. The adult flies at dusk. The life 

 cycle lasts nine weeks. Like B. isthmia, it skeletonizes 

 the leaves, and is therefore conspicuous. On some 

 estates it has been held in check by cutting down the 

 nests and crushing the larvae, at the cost of two cents 

 per nest. In the same island the larvae of Hyper chiria, 

 called the " spiny coco-nut caterpillar," skeletonize the 

 leaves. This species is gregarious, but not nest-building. 

 So far it is not a serious pest. 



Omiocles blackburni, "the palm-leaf roller," is a 

 Pyralid moth reported on coco-nuts in Hawaii. Preuss 

 reports larvae apparently of the same family, which 

 destroy young nuts in New Guinea. A Tineid moth, 



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