4 



Geographical Distribution. 



Diatrma saccharalis appears to be a native of South. America and the West Indies, or it may have 

 originally occupied a limited area on the continent, and spread since the cultivation of the sugar-cane 

 became general. 



As related above, it has long been known from Jamaica. Guilding (4.) recorded it from St. Vincent 

 in 1828. Comstock (10.) refers to its ravages in the Windward Islands, and particularly in Guada- 

 loupe, in 1785 and 1786. Mr. Smith (24.) refers to its occurrence in the Lesser Antilles, mentioning 

 St. Vincent and Grenada. Miss Ormerod (9.) records it from British Guiana. Mr. E A. Schwarz 

 found it in the Bahamas. In the United States it has been found to attack maize and sorghum, as well 

 as sugar- 

 noticed 

 Ashmeac 



relates that Mr. Pergande found the larvae in Tripsacum at the southern end of the Long Bridge c'ros^ 

 ing the Potomac River at "Washington. Townsend (23.) found it in New Mexico, and it is reported by 

 Weed from Mississippi. In Kit Carson Co., Colorado, a Corn-stalk Borer appeared in 1889, which 

 the present writer (18.) suggested might be Diatnea. 



It is a remarkable circumstance that in the United States it appears to be spreading northwards. 

 At the 1891 meeting of the Association of Economic Entomolgists, Mr. Howard said " that this species 

 is spreading northward rapidly through the Southern States and has reached the southern border of 

 Maryland, but that it is not a pest to be feared with the methods of careful cultivation in vo»ue at the 

 north." 



It has also been reported from the Sandwich Islands (11.) In the Oriental Region, Cotes (17.) 

 reports it as injuring sugar-cane in India. Westwood (6.) in 1856 wrote an article on the Cane-borer 

 of Mauritius, which had been called Procerus sacchariphagus, and considered it probably identical with 

 that described by Guilding. However, he gives a description of the Mauritius larva (see Howard, 21.) 

 which is evidently different from ours. In Java, Dr. Kruger (20.) records four different borers, one of 

 which, Diatrwa striatalis, Snellen, occurs also in Bor. eo, Sumatra, and Singapore, and according to 

 Howard (21.), almost exactly resembles the West Indian insect. In Queensland, Mr. H. Ling Roth 

 (12.) found a species, which he believed identical with D. saccharalis. 



Injuries. 



The loss occasioned by the borer, in Jamaica as elsewhere, is very considerable. 



Mr. D. A. Van Putten writes from Roaring River Estate under date 25th March, 1892 : 



" I now send you two pieces of cane, and a small phial with one of the worms in rum. The whole 

 cane becomes rapidly dry, and the leaves perfectly dry, so that the stock will not feed on them, and 

 the short top is useless for planting. 



" The crop will fall off very much. We had estimated for 140 tons, but will not make more than 

 115 tons of sugar. Our neighbours I see are also affected with it." 



The worm sent is immature, but evidently the larva of D. saccharalis. The canes have a very 

 dried-up appearance, with tunnels in the centre of the pith. They are also attacked by two or three 

 species of fungi, which probably follow the decay due to the borer. 



It is scarcely necessary to enumerate the various accounts published concerning the damage done 

 by the borer. Extracts bearing on this point are given above from Guilding and others. According 

 to Comstock, Dr. J. B. Wilkinson states thit in 1857 the borers were very abundant along the Lower 

 Mississippi, the crop upon one plantation being utterly destroyed, as the canes broke to pieces without 

 cutting. 



Westwood (6.) was informed that the borer was very destructive in Jamaica about 1845. 



Food- plants other than Sugar-cane. 



In the United States, D saccharalis has been found to severely attack maize (Zca mays) ; and 

 Thompson (19.) writing from Louisiana, reported that sorghum (Sorghum vulgare) appeared to be far 

 more viciously attacked than tropical cane. Another food-plant is Tripsacum dactyloides, or gama grass, 

 in which the larva; were found by Mr. Pergande at Washington. The occurrence of the borer in a 

 wild grass may be of considerable practical importance, as it would be almost useless to kill the borers 

 in the canes it they were breeding abundantly in an adjoining grass-patch. Grass growing near cane- 

 fields should therefore be examined, and if found infested, burned at suitable intervals. 



Remedies. 



In Gosse's (5.) work, there is a quotation from a letter of Mr. Stephen Hannaford of St. Dorothy, 

 to Mr. Hill, as follows : — 



" The system of trashing and of keeping the canes clean is the best and surest method, as well to 

 prevent the depredations of the borer, as to improve the juices. In seasonable districts, where this 

 system can be fully carried out, the mischievous effects of the borer seem to betray a want of proper 

 attention on the part of the manager to his field. But in districts subjected to long spells of drought, 

 the utmost caution is necessary. It is generally observed that the borer commits the greatest injury 

 to the cane after a rapid growth, which is followed by a spell of dry weather, whilst vegetation seems 

 not only suspended, but the plant itself struggling for life. In this dilemma the planter chooses the 

 least of two evils. To trash his canes under such circumstances would prove almost, if not entirely, 

 destructive to his field ; he is, therefore, compelled to suffer the borer to proceed unmolested, until rain 

 has fallen, and the plant has again started into life. Then the removal of all the loose trash from the 

 the cane will check the progress of this insect, and by following up this operation as often as the canes 

 require to be freed from superfluous trash the borer ceases to effect further perceptible injury." 



