THE SUGAR-CANE BORER. 



(Biatrwa saccharalis, Fabr.) 



By T. D. A. Cockereix, F.Z.S., F.E.S., Curator of the Institute of Jamaica. 



History. 



Sir Hans Sloan e, in his book en Jamaica (1.*) refers to the worm eating the sugar-canes, which he 

 describes as not over one-third of an inch long, not so thick us a|hen's quill, and of a reddish brown 

 colour. In all probability, he observes, it is some sort of butterfly, moth, beetle, or weevill, which 

 thrusts in the egg, from which the borer hatches, and feeds on the cane until it be ready to turn into 

 an aurelia, when it comes out, and leaves a greyish skin, which he often found in the spoiled canes. 

 The canes so eaten are not fit to make sugar, and therefore are ground to make rum, or given to the 

 hogs to feed on. 



The perfect insect was not seen by the author, and thus we are left in doubt as to the species, the 

 more so, because the larva is said to be reddish-brown, which is not the case with the insect now to be 

 considered ; nevertheless it is highly probable that part at least of the damage complained of by Sir 

 Hans Sloane was due to our insect. 



In 1793, Fabricius (2.) described a moth from South America as Phalcena saccharalis, which is 

 doubtless the same species as our Sugar-cane Borer ; although Zeller, according to Comstock, (10.) 

 was of opinion that the description given would apply to any one of several allied species. Turton (3.) 

 gives a translation of the Fabrician description, as follows : — 



" Wings striate cinereous, the hind margin dotted with black. Inhabits South America, in the 

 sugar-cane, which it dries up and destroys ; is very destructive to plantations. Body small cinereous 

 immaculate ; upper wings sometimes immaculate ; lower wings white immaculate. Larva 6-footed, 

 pale hyaline with a reddish-brown head and 8 dots each side ; pupa naked long, chestnut-brown with 

 numerous short raised spines before." 



The statement "larva 6-footed," must be taken as applying only to the thoracic or true legs; the 

 total number of legs is 16. Howard (21.) conjectures that the original specimens may have come from 

 Dutch Guiana, which is the more likely, because the description of the larva was drawn up from a 

 figure by Myhlenfels. 



About 35 years later, the Rev. Lansdown Guilding (4.) wrote a memoir on the insects infesting 

 the sugar-cane in the island of St. Vincent, an extract from which is given by Gosse (5.) in his 

 " Naturalist's Sojourn in Jamaica." Mr. Guilding described the borer as a new genus and species, 

 Diatrcea sacchari, and wrote of it as follows : — 



" By far the m«st destructive and common enemy is the smaller grub of the Borer-moth. . 

 The sugar-cane is never exempt from this dreaded pest. In the seasonable island of St. Vincent, from 

 improved cultivation, the animal is not very formidable ; but in some other of our colonies, which, 

 from the absence of mountains, or other causes, are subject to dry seasons, it has been known to blast 

 the hopes of the year, to destroy whole acres of canes, and to ruin the unfortunate planter." 



In 1856, Westwood (6.) wrote an article on the Sugar-cane Borer, and pointed out that it was 

 apparently first described by Fabricius as Phalcena saccharalis. This identification has been generally 

 accepted, and while some have referred the insect to the genus Chile- Zinck., most writers on the sub- 

 ject have recognised Guilding's genus as valid, calling the species Diatrma saccharalis (Fab.) 



Two other specific names have been given to the insect, namely obliteratellus, Zeller (8.) and cram- 

 bidoides, Grote. 



Descriptive. 

 Egg. 



The egg, as described by Comstock (10.) is flat and circular, one twenty-fifth of an inch in diame- 

 ter, milk white with a faint greenish tinge when first deposited, turning orange-yellow when about to 

 hatch. Seen with a microscope the whole surface is coarsely facetted. 



Larva. 



The newly-hatched borer, (again quoting Comstock) is " about 2 millim. long, broad at the head 

 and tapering towards the end. The colour is orange-yellow, but each segment bears a row of reddish 

 warts which give the whole larva a reddish appearance. The head is black, polished and very flat, and 

 is of a very convenient shape for an entering wedge in forcing its way between leaf and stalk." This 

 description was made from specimens infesting maize in the United States, but there seems to be little 

 doubt that the species is identical with ours. 



Mr. L. 0. Howard (21.) comments on the considerable difference between the several published 

 descriptions of the adult larva. These differences are such that one might well suppose that several 

 species had been confounded under one, but experience has shown that the larva is extremely variable, 

 as well as the moth. Prof. Riley examined a long series of the moths, reared from both corn and 

 6ugar-cane, and came to the conclusion that they must all be referred to a single species. Gosse (5.) 

 writes : — " The caterpillar is of a yellowish colour, spotted with faint black dots, and in a slight degree 

 hairy." The larvae from British Guiana described by Miss Ormerod (9.) were also spotted, but she gives 

 no detailed description. 



* The numbers following authors' names refer to the Bibliography given at the end. 



