THE PESTS AND DISEASES OF THE CANE 151 



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

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

 are larval parasites except the fungus, which attacks the perfect insect. 



Beetle Borer. Rhabdocncmis obscurus by a tachinid Ceromasia sphe- 

 nophori and by the green muscardine fungus. 



Hzmiptera. In Mauritius, Icerya seychellarum (pou-a-poche blanche) 

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

 myramid egg parasites, Paranagrus perforator, P. optabilis and Anagrus 

 frequens ; and in the perfect stage by a dryinid, Ecthrodelphax fairchildii, 

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

 saccharivora (cane fly) by a myramid egg parasite Anagrus armatus, and 

 in the perfect stage by a dryinid Strepsiptera sp., by a fungus Fusarium 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 strychnine, 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 

 " grey back " beetle Lepidiota albohirta. 



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 many estates can be easily trained to perform this task. It 

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

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

 results they have been known 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, Apogonia 

 destructor, Zehntner devised the trap shown in Fig. 45, which is exposed 

 under a lamp during the period of their nuptial flights. 



Exceptionally, as in the case of the slow-flying diurnal, Castnia licus, 

 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 24 has recorded that with sour cane and with the help of seven 

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



