CANE SUGAR. 



egg mass of Scirpopliaga intacta ; all these are after Van Deventer. The 

 leaf-eating lepidopterous pests, are neither in the extent of their destructive- 

 ness nor in the permanency of their attack to be compared with the Borers ; 

 their attack seems to be sporadic and to rise and fall with many factors. Thus 

 the * army worm ' (Leucania unipuncta) is known to attack cane and corn after 

 floods which have forced it to leave its usual habitats. The damage is chiefly 

 to young cane, the leaves and not the stem being attacked ; except in severe 

 cases the cane recovers, and suffers only a temporary check in growth. 



Coleopterous Pests. The Coleoptera (beetles) are equally destruc- 

 tive with the Lepidoptera, and, as with the latter, it is chiefly the larvae that do 

 the harm, although in some cases it is the perfect insect that attacks the cane. 

 The term ' Borer ' is also applied to some of the beetles, and in fact, in the 

 Hawaiian Islands, this term is confined exclusively to the ' Weevil Borer ' 

 (Sphenophorus obscurus) ; an allied insect, S. sericeus, is also known as a Borer 

 in the "West Indies. 



Amongst the major coleopterous pests of the cane attention may be called 

 to the Walwalan Beetle (Apogonia destructor] of Java, the West Indian Root 

 Borer (Diaprepes abbrematus), the Cane Grub (Lepidoderma alboliirta} of 

 Australia, the Louisiana Beetle Borer (Ligyrus rvgiceps], and the Weevil 

 Borer (Spenophorus obscurus) of the Hawaiian Islands, Fiji, Australia, and 

 New Guinea. The damage done by the first four above-mentioned pests is due 

 to the larva, which passes its life underground, eating the roots ; the fifth is 

 a stern borer. Figs. 51, 52, and 53* after Yan Deventer, show a piece of soil 

 containing the grubs and the larva and perfect insect of Apogonia destructor. 



The life history of the West Indian Root Borer has been worked out by 

 the Rev. N. B. Watson, 7 whose description of this pest is appended : 



" In August and September the perfect insect lays its eggs on the upper surface 

 of the leaves, and after ten days the grub emerges and falls on the ground, 

 immediately burrowing into the ground in search of food. The grub remains in 

 the soil for 312 days, eating the roots of cane, sweet potato, &c., and then pupates, 

 the perfect insect emerging in fifteen days to repeat the same cycle. The grub at 

 first is only ^ inch long, reaching at maturity a length of one inch. 



In Fig. 5Jj* is shown the Weevil Borer, and in Fig. 55* a typical piece of 

 damaged cane. The life history of this insect as it occurs in the Hawaiian 

 Islands is thus given by Koebele 8 : 



" The female beetle is easily separated from the male by its longer, smoother, 

 and more slender beak, and its pointed terminal segment. She lays her eggs con- 

 secutively, probably four to eight each day, but less than this toward the end of 

 the period of six or eight months during which she continues to lay. When the 

 egg is laid in the cane from the outside, this is done from under the sheath, which 

 the beetle can brace against; with the prominent saw-like movable teeth laterally 

 she first begins to eat out the hole until softer ground is struck, so to speak, when 

 she will force the work, moving the head up and down as well as sideways until the 

 whole length of the beak is buried. Upon soft parts on split cane this operation 



* See Frontispiece. 



130 



