20J 



THE AGRICULTURAL NEWS. 



Junk 28. 1919. 



INSECT NOTES. 



BATOCERA RUBDS. 



The Department of Agriculture, Mauritius, has issued 

 Ltafltt No. 10, entitled The Mango Tree Borer (^Batoeera 

 rufius). This insect is a recent introduction into the West 

 Indies, and on this account the information given in the 

 leaflet is likely to be of interest to readers of the Agri- 

 cultura/ JVars. 



The first record of the occurrence of Batocera rubus in 

 the West Indies appears to be the account in the I'roceedings 

 ofth( Agviculturnl Society of Trinidad and Tobago (Vol. XI, 

 p. 342), when Dr. Fredholm stated that this insect had made 

 lis appearance in Trinidad and in St. Croix, and that it 

 might prove a troublesome pest if it should become established 

 »ad be spread to other islands. 



Accounts of this insect were published in the Agticul- 

 tural News (Vol. X, p. 298, and Vol. XV, p. 74) Since 

 that time Batocera rabus has become known in the Virgin 

 Islands, where it .seems to be well established. 



According to Leaflet No. 10, this insect is known in 

 Mauritius as the .Mango tree borer because it is responsible 

 for considerable damage to mango trees in that island. It 

 is called ' Violin ' because of the peculiar noise it 

 m&kes when irritated. The noise is produced by the rubbing 

 of the posterior part of the thorax on a small, smooth, 

 black strip provided with ribs across it, and which is in 

 front of the scutellum. This strip is hidden from sight 

 irh*n the beetle is at rest. 



This is said to be the largest beetle found in the colony 

 of Mauritius, and the following description is given of it. 

 It is from •'JO to 5.o mm. long and 18 ram. wide at the base of 

 Ibe elytra. It is of a chocolate brown colour, more or less 

 covered with an orchreous, short, thick pubescence, which is 

 ehsily rubbed off and is less noticeable on the antennae and 

 legs than on the body. The antennae of the male are very 

 long, reaching to »he extremity of the abdomen ; the female 

 has shorter antennae. 



The thorax and the base of the elytra are provided 

 laterally with a strong spine. There exists on the middle of 

 the thorax two large, irregukr, red .spots .slightly reniform, 

 which are contigiioui at the apex, and diverge posteriorly. 

 Th« base of the elytra is very rough, and covered with small 

 (jranulations. The scutellum is of a pure white colour. 

 There exists under the body and along its sides a large 

 white stripe which slightly encircles the eye, and 

 coatinucs up to the pygidium or last abdominal segment. 

 The larva ii a large grub, cylindiical in .shape, of a creamy 

 white colour, reaching a length of 75 mm., and a width of 

 18mre. at the widest part of the body which is the thorax, the 

 three segments just behind the head. From the thoracic 

 •egments the body tapers off gradually to the last segment. 

 The grub is footless and blind. It lives in the wood and 

 nnder the bark of the trees attacked. 



The eggs are deposited by the female beetle singly in 

 cracks and crevices in the bark. The young larvae remain in 



the bark for the greater p^irt of their lives. The galleries 

 which they bore are irregular, narrow, and sinuous. When 

 they are 40 to 45mm. long they bore into the wood and make 

 lirger, circular galleries which finally reach the outer surface 

 of the tree immediately beneath the bark, where they 

 transform into pupae and adult insects. 



Although they are concealed in the trunk ami branches 

 of the mango tree.?, t'jeir presence is easily detected by the 

 brownish fluid which trickles out from the wound. When 

 they are still under the bark, the tree can be treated and 

 saved from destruction; but when they are in the wood 

 there are no practical means whatever of destroying tliem. 



The life of the larva has not yet been ascertained, but 

 there is groand for believing that it is not less than a year. 

 The adult insect or beetle is found all the year round, but 

 in greater numbers in summer, at which time the first attacks 

 of the larvae are noticed. 



Control measures include the collecting of the beetles 

 and the destruction of the larvae. In the case of trees in 

 which the borers are un 'er the bark, and have not penetrated 

 into the wood, the grubs may be dug out, and the galleries 

 cleaned of debris to promote more rapid growth of new 

 tissues. 



Trees which are too badly attacked to be saved should 

 be cut down and split up into small pieces so as to get out 

 all the grubs. Logs or large pieces of such infested trees, 

 or dead trees if left standing, will continue to breed these 

 insects, or at least all the grubs in them will be able to 

 complete their development, and come out as beetles. 



This borer is stated to occur in Madagascar and Rea»ioa 

 as well as in Mauritius, and to attack, in addition to the 

 mango, the Banyan tree, the Golden Apple (Fruit de 

 Cytheie), the Rois Noir, and to show a marked preference 

 for the Kappok tree, the cultivation of which has been givem 

 up in the colony as a result of the attacks of thi.s insect. 



Batoceri rubus is a native of the East ; it occurs in 

 India, Ceylon, and sometimes in Africa, in addition to the 

 localities already mentioned. In the West Indies it is re- 

 corded in Trinidad, St. Croix, Tortola, St. Thom>»s, and 

 Jost van Dykes. 



The grubs of this species attack the following trees : 

 Ficus elastica and other species of Ficus, the hog plum 

 (Sf>ondias lutea), avocado pear (Pers(a gratisfima), mango 

 (MiDigifcra indica), silk-cotton (Eriodfndron anfraC' 

 tu(num), cork wood (Ochroma lagopus). It is reported as 

 having been a serious pest of coco-nut trees in Ceylon, and 

 to have occasionally attacked Para xv^th^t (Heveabrasiliensis) 

 in India. It also attacks the papaw (CVjr/V<j/rt/}(iv(i). 



In July 1916, an attempt was made in Tortola to 

 collect certain insects with the view of finding whether they 

 were present in lar^e numbers. One of the.se insects was 

 Batocera rubus, and in four days a few children collected 

 266 of these beetles, which were paid for at the rate of one 

 cent each. This would indicate that the insect is fairly 

 common in Tortola. 



PROTECTION OF STORED GRAIN PROM 

 INSECT ATTACKS. 



The need for the utmost con.Mervation of foodstuffs as a 

 result of war conditions induced investigation into the means 

 to be adopted for preventing the losses which have in the 

 past been so prevalent in the case of stored grains. 



