328 



THE AGRICULTURAL NEWS. 



October 10, 19U. 



INSECT NOTES, 



A WOOD-BORING MOTH. 



The following letter trcnu the Agricultural Iiistruetor, 

 Nevis, to the Imperial Comuiissioiier of Agriculture again 

 falls attention to the ravages of this wood-lioring moth whieh 

 is injurious to a wiilo range of trees and shrubs, and is gene- 

 rally distrilnited in the Lesser Antilles: — 



' I beg to forwarii specimens of a grub fnund boring into 

 the stems of orange and tangerine trees. The grub attacks 

 fairly large stems, tunnelling in the hard wood. The stems 

 which are attacked remain green for a fairly long time after 

 the hard wood is practically destroyed, especially if the 

 weather is favourable; liut the whole stem eventually dies. 



'I am also forwarding a piece of the stem showing the 

 damage done. This was cjuite green when taken from the tree." 



Examination of the specimens referred to above indicates 

 tliat the ' grubs' are the caterpillars of the moth Duoiintiis 

 punctiter, Hampson. The piece of stem (.' tangerine) men- 

 tioned in the letter, appears to show an attack of this insect 

 in an advanced stage with certain minor peculiarities which 

 will be mentioned later. 



Dvomitus jmnclifer was described and figured as a new 

 species by Sir Geo. Y. Hampson, liart., B.^V., in a paper 

 entitled 'The Jloths of the Lesser Antilles', which wasjiublish- 

 ed in the Transactions of the Jiniojitolor/iral Society, London, 

 Part III, September, 189S. This paper gave an account nf. 

 moths of certain families collected by Mr. H. H. Smith in 

 St. Vincent, Grenada and the Grenadines, with certain 

 records (Dominica and St. Lucia) of insects collected by 

 Mr. W. H. Eliott. In this paper, the distribution of D. puiir 

 tifer is given as Dominica, St. Lucia. St. Vincent and 

 Grenada. 



Injuries to trees similar to those now known to be 

 cau.sed bj' this insect have been observed in the Lesser 

 Antilles for a number of years, but in most cases only the 

 larvae were found and in some only the tunnels caused liy 

 them 



The first pulilished account of these injuries definitely 

 ascribed to the attacks of Biu/iuitus jninctijir appears to be 

 tliat included in the Annual Report of the Baibados Depart- 

 ment of Agriculture fur 1912-13, where the A.ssistant 

 Su|jerintendent of Agriculture gives an account of the life 

 histnry. with de.scrijrtions of the larva, j>ui)a and adult, the 

 nature of the attacks and the remedies to be adopted for their 

 control. The plants there recorded as attacked are the 

 white wood ('/ecoiiui Itiwo.rylun), soursop (Anona mtiriaita), 

 Ipomoea spp., and ornamental crotons (Codinevrn spp.). 



Dnomitus punctiter is- a moth of the family Cossidae 

 wliich includes a number of species the larvae of which are 

 borers in the woody stems and branches of trees and shrubs. 



The adult of this species is grey in colour, slightly 

 tinged with pink, the body is tapering and spindle-.shaped 

 and the wings are rather narrow, giving a genei-al appearance 

 .somewhat like that of the hawk moths. The female moth 

 has a wing expan.se '^f aliout '21 incJU's; the male is somewhat 

 smaller. The male is an active tlyer and is frequently 

 attracted to light. The female does not fly so readily, at 

 least until after the eggs are laid. 



The eggs are laid in or on small twigs. The hatching 

 larvae tunnel through these to the larger branches. The 

 fully grown caterpillars are sometimes as much as 2 inches 

 in length. The colour is a dirty white with a yellow 

 'cervical' or prothoracic shield; the mouth parts are dark brown. 

 When the larva is about to pupate it eats its way 

 toward the surface, and leaves a thin film of liark as 



a cover to the exit from its tunnel; and then, drawing back 

 a .short distance into the tunnel, it j)U])ates. The j)U|)a is 

 naked: the abdominal segments are armed with rows of back- 

 wardly directed sjiines and the head bears a stout spine 

 which projects forward. When the moth is about to 

 i-merge, the pupa ^^•orks itself forward l\y means of the 

 alidominal spines, breaking the thin cover of liark over 

 the exit of the tunnel, b}' means of the spine on the head, 

 until it (the pupa) stands out from the surface of the bark by 

 nearly half its length. The pupa case then siilits open and 

 the moth crawls out. The empty pupa cases may often lie 

 seen projecting from the tunnels. 



A chai-acteristic feature of the tunnels of this moth is to 

 be found in the partitions which are built acro.ss the tunnels 

 at ititervals. 



The food plants of this insect would appear to ln' many. 

 As lo)ig ago as 1900, a Ijorer in the stem of coffee, was re])orted 

 as doing considerable damage in Nevis. This insect was not 

 identified, but it was stated to belong to the family Gossidae, 

 and was jirobably this species. A few years later, camithor 

 trees grciwing at the Botaidc Gordens at St. Kitts were 

 severely injured b}' the larvae of a Cossid moth, which has 

 since been identified as Duo'ndtus punctifer, and .since then 

 (1912) this insect has been recorded attacking the Nicaragua 

 shade tree [Giiiicida maculota) in the same locality. 



In Antigua, the soursop has been attacked by a borer 

 which is believed to be the same insect. In Montserrat, it 

 has been found tunnelling in sapodilla trees (Achmx aapola). 

 In St. Lucia, it has been reported in guava, in St. Vincent, in 

 Pitliecolobium acunan. 



In the case of the section of stem of tangerine from 

 Nevis, mentioned at the beginning of these notes, a peculiarity 

 occurs which is worthy of remark. The attack in this stem has 

 been of many years' duration, judging from appearances. 

 Several of the openings of the tunnels have entirely healed 

 over by the growth of a callus, while others give the im- 

 pression that the caterpillar ate right through the bark not 

 leaving the usual thin protective layer of bark r>ver the mouth 

 of the tunnel. It is likely, however, that the insect followed 

 its characteristic custom, and that the unusual ajipearance is 

 due to the fact that the strong growth of callus under the 

 bark forced fill' the remnants of the thin covering over the 

 tunnel, giving the impression that the larvae had eaten it 

 away. 



It has bevn oliserved that often, if not always, tlie 

 tunnels of Duomitu-t puticti'er in the smaller liranches of the 

 whitewood are infested by a mealy-bug which sometimes 

 occurs in large numbers. 



The remedies are the ii-siutl ones for wood boring lai'vae. 

 Badly infested trees or portions of trees should lie cut and 

 liurned. In other cases, the larva may be killed by proljiug 

 with a strong wire, or they may sometimes be removed by 

 means of a wire hooked at the end. Carbon bisuliihide in- 

 jected into the tunnels is also a satisfactory means of killing 

 the larva. The partitions across the tunnels should first be 

 l)roken by proliing with a wire, and after the carbon bisul- 

 phide has been injected, the tunnels should be stopped bj- 

 means of wet clay, wax or soap. Carlion liisulphide is 

 a volatile and infiannnable liipiid, and no fii-e or light should 

 be brought near it. 



In all cases where severe injury to trees and shrubs has 

 been repoited, the attacks appear to have been continued 

 over a long time. A little obser\ation should enal)le the 

 presence of this -insect to be discovered before the injury has 

 become so severe, and it should lie possible to check the 

 attack in its earlier stages. 



