THE PESTS AND DISEASES OF THE CANE 151 



Elis atrata. In Hawaii Anomala sp. by a scolid Tiphici sp. In Australia 

 Lepidiota alhohirta (cane grub) by a scolid Dielis formosus. All the above 

 are lar\'al parasites except the fungus, which attacks the perfect insect. 



Beetle Borer. — Rhahdocncmis obscurus by a tachinid Ceromasia sphe- 

 nophori and by the green muscardine fungus, 



Hemiptera. — In ^lauritius, Icerya seychellarum (pou-a-poche blanche) 

 by a chalcidid. In Hawaii, Perkinsiellia saccharicida (leaf hopper) b^' the 

 m}Tamid egg parasites, Paranagrus perforator, P. optabilis and Atiagrus 

 freqiiens ; and in the perfect stage by a dninid, Ecthrodelphax fairchildii, 

 and by a chalcidid, Ootetrastichus heatus. In the West Indies, Delphax 

 saccJiarivora (cane fly) by a m\Tamid egg parasite Anagrus armatus, and 

 in the perfect stage by a dr^inid Strepsiptera sp., by a fungus Fusariitm sp., 

 by ants, and by swallows. In Trinidad, Thomaspis posticata (frog-hopper) 

 by a reduviid bug, Castolus plagiaticollis, by a chalcidid Oligosita giraulti, 

 and by the green muscardine fungus. In Hawaii, Trechocorys calceolaria 

 (mealy bug) by lady-bird predators and by the fungi Entomophthora pseudo- 

 cocci and Aspergillus parasiticus. 



Other Methods of Control. — i. Use of Poisons. — The use of poisons is 

 largely confined to the destruction of rats. The poisons that are most 

 commonly employed are preparations of strj^chnine, arsenic, squills, phos- 

 phorus, and barium. Bread grains, banana, and molasses are food media 

 used to distribute the poisons. 



Leaf-eating caterpillars are to some extent controlled by the use of 

 arsenicals, sold under the trade names of " Paris Green " and " London 

 Purple." These materials have been used in the campaign against the 

 " giant " moth borer in British Guiana. In Australia the injection of 

 cyanide of potassium into the soil has been used to destroy the grub of the 

 " gre}' back " beetle Lepidiota alhohirta. 



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

 a diminution of insects is obtained by means of hand collection. In regard 

 to the moth borer this collection takes the form of cutting out the " dead 

 hearts " of the injured cane and the collection of the eggs laid on the leaves. 

 The children of the Asiatic and negro labourers forming the bulk of the 

 population of man}' estates can be easily trained to perform this task. It 

 is important that they be taught to recognise the difference between para- 

 sitized and sovmd eggs, and this they readily do. Further, when paid by 

 results thev have been kno%vn to collect and substitute the egg masses of 

 other insects. Zehntner in Java recommended that the collected eggs 

 should be placed on trays surrounded by a layer of molasses, which would 

 prevent the escape of the caterpillar, but allow the parasite, which emerges 

 as a perfect insect, to fly away. 



The night-flying coleoptera and lepidoptera may be captured by exposing 

 lamps in infected areas. For the capture of the wawalan beetles, .4 />o^o>n'a 

 destructor, Zehntner de\-ised the trap sho\\Ti in Fig. 45, which is exposed 

 under a lamp during the period of their nuptial flights. 



Exceptionally, as in the case of the slow-fl\-ing diurnal, Castnia liens, 

 the perfect insect may be caught in quantity in nets. The employment of 

 bait as a means of attracting insects was once used in the Hawaiian Islands, 

 and Koebele^^ has recorded that with sour cane and wixh the help of seven 

 httle Indian girls in Fiji he has collected 16,000 beetles in four hours, and 



