THE PESTS AND DISEASES OF THE CANE. 



1. Poisons. The use of poisons is practically limited to the destruction 

 of rats. The poisons chiefly employed for this purpose are preparations of 

 strychnine, arsenic, phosphorus, and barium ; bread, grains, bananas, and 

 molasses are used as food media upon which the poisons are distributed. 



Leaf-eating caterpillars are in some instances destroyed by dusting the 

 leaves of the plants upon which they feed with sundry arsenical preparations, 

 of which those known as ' Paris Green' and London Purple ' are mostly 

 used. Leaf-eating caterpillars are not amongst the most serious pests of the 

 cane, and in practice it would be impossible thus to control them on a large 

 estate. 



2. Collection by Hand. In districts where labour is plentiful and cheap, 

 a diminution of the insect pests is obtained by hand collection. This collection 

 takes the form of cutting out the ' dead hearts,' i.e., the young cane attacked 

 by borers, and the collection of the eggs of the moth laid on the leaves of the 

 cane. The children of the black or Asiatic labourers forming the bulk of the 

 labour supply of most sugar producing districts can readily be trained to perform 

 this work. In the collection of eggs it is of importance that the parasitized 



FIG. 57. 



eggs be not destroyed. Following the advice originally given by Zehntner the 

 eggs should be placed on a dish surrounded by a layer of molasses ; the parasite 

 from parasitized eggs emerges as a perfect insect and is able to escape, the 

 molasses preventing the escape of the caterpillar from the unattacked eggs. 



The night-flying coleopterous and lepidopterous insects can be captured 

 by exposing lamps in infected areas ; these lamps are exposed over trays of 

 molasses which prevent the escape of the insect. For the capture of the 

 Wawalan .Beetle (Apogonia destructor} of Java, Zehntner 2 has devised the 

 trap shown in Fig. 57, which is exposed under a lamp at night during the 

 time that the beetles make their nuptial flights. 



The employment of bait as a means of attracting insects is also in vogue 

 in the Hawaiian Islands, and in Fiji it has been observed that the Weevil 

 Borer is attracted by sour cane; Koebele 3 records that in Fiji, with the 

 help of seven little Indian girls, he has thus collected 16,000 beetles in four 



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