10 



THE AGRICULTURAL NEWS. 



January 



19U. 



INSECT NOTES. 



Jl fungus parasitic on the coco-nut 



BEETLE. 



According to an article in Tropical Lije for November 

 last, a correspondent of that paper writes from Samoa to the 

 effect that an efficient fungus parasite has been discovered 

 in that island, as an enemy of the coconut beetle. 



It would appear that Dr. Friederichs, Government 

 Entomologist of Samoa, occasirin^illy discovered these beetle 

 larvae with small brovvn spots on their backs Exam- 

 ination proved that the spots were the pninls of attack 

 of a fungus, indigenous to Sa'nua, which finally causes the 

 death of the insect. 



After conducting experiments extending over several 

 months, it has been discovered that artificial cultures of the 

 fungus can be made in traps which attract the adult insect. 

 The traps, or nests, as they are called, are in general principle 

 constructed as follows: A spiice of about 6 feet square is 

 enclosed b\' a slone wall or other fence some 15 inches 

 high, ard this is filled with rotting busks, old coco nut and 

 other rotting wood; and in addition, on the top of this 

 material, 3 or 4 bigs of fresh coconut husks are spread. 

 The whole surface is then covered with 4 or -5 inches of 

 soft earth, Hud this forms the trap which seems very attrac- 

 tive to egg-laying females which come to it in great numbers. 

 The mass of mould and rotting vegetable material is infected 

 with the fungus from vrtificial cultures, which are made 

 as follows: Large numbers of beetle larvae are captured 

 and confined in boxes, kerosene tins, etc , which are tilled 

 with rutting wood and coconut husks, into which are 

 introduced from time to time large numbers of infected 

 beetle larvae. 



The results obtained from these artificial cultures 

 •were discouraging at first, but it is now believed 

 that a virulent type of fungus has been developed 

 which can he conveyed in the mould from these cul- 

 tures to the traps already mt-ntioned, where the growth 

 of the fungus results in the death of the newly hatched 

 beetle larvae while they ure still very young. It is 

 stated that these nests are being built by pl<tnters about 

 one to the acre throughout the co.'o-nut plantations, 

 extending into tie wild land on all sides for a short distance, 

 and it is expected that a very considerable amount of benefit 

 will be derived from this method of dealing with the pest. 



It ,should be borne in mind, however, that the greatest 

 care will have to be taken in all the adjacent land to remove 

 the native breeding places of the coconut beetle, otherwise 

 many eggs will be laid under the ordinary conditions, and 

 this will necessitate a continuance of the practice on a large 

 scile over a much longer period. 



It i'* further stated that on one plantation the results 

 •of this jjnictice have been so satisfactory that it has been 

 found difficult to collect any full-grown larvae, the only 

 grubs seen by the men who were collecting having been the 

 small ones only a tew days old It is still too early to state 

 ■anything definite with regard to the beneficial results obtained, 

 but as far as observations are reported, it would appear that 

 the method is a very satisfactory one. 



Trofical Life'i correspondent in Samoa does not give the 

 name of the coconut beetle. On reference to the Aqri- 

 ■cultural Netvs for July G, 1912 (Vol. XI, p. 218), it will be 

 seen that the rhinoceros beetle (Ori/ctex rhinoceros) is a serious 

 pest of coconuts, and this may be the species referred to. 

 ■■The question naturally arises as to whether this form of 



trapping or the use of the fungus, or both together, might 

 be profitable in the West Indies. 



Mr. Frank F -lepson, I!. A., F.E S., Government Entomolo- 

 gist, F'ji, visited Samoa during April 1912, for the purpose 

 of in\estigating the rhinoceros beetle, and a report of this 

 visit was published as Bulletin No, 3 of the Department of 

 Agriculture, Fiji; entitled, The lihinoceros Beetle {Orydes 

 rJiiiioceroi, Linn.) in Samoa. 



During this visit .\Ir. Jepson found traps, similar to 

 those already described, in use; but he does not mention the 

 parasitic fungus. The traps were at this time employed to 

 form attractive places for egg-laying, and ia them the devel- 

 oping insects were destroyed cither by the use of carbon 

 b iulphide or by men and boys who searched the decaying 

 vegetat'le matter for the grubs and killed them. 



From the following, which is quoted from page 17 of 

 hi-i report, it is further shown that the fungus was not known 

 at the time of Mr. Jepsou's vi.-ic. The discovery of the 

 parasitic fungus and the method of using it appear to be 

 recent developments, and indicate one me;ins by which an 

 introduced pest is made to fit ino the environment of a 

 new locality. 



'One is led to believe that the only successful means of 

 combating this pest is by the agency of its natural enemies. 

 The pest has been established in Ceylon, perhaps, for centuries, 

 and yet it is hardly regarded as a very formidable enemy. It 

 would appear, therefore, that there is some natural cause co 

 account for this, and the most easily accepted theory is that 

 there occurs in that country a natural check of .some kind. 

 The fact of the beetle not being regarded in any very serious 

 light there, probably explains the reason why no research has 

 been undertaken on the matter The persons interested in 

 ('eylon are not aware of the presence of any natural enemy, but 

 possibly, if the pest was a more formidable one, the matter 

 might have had more attention This insect having been 

 introduced into Samoa, where it does extensive damage, from 

 Ceylon, where its ravages are not so serious, leads one to 

 believe that the pest, was introduced while its natural enemies 

 were left behind.' 



HOW ORYCTES RHINOCEROS, A DYNAS- 

 TID BEB.TLE, USES ITS HORN. 



The following note, which appeared in Science for 

 December 19, 1913, is of interest in connexion with the 

 reference to the rhinoceros beetle which appears on this page. 



'The horn is present on both sexes and is usually 

 longer on the male than on the female, but many males may 

 be found with very short horns and many females with long 

 horns, so that the sexes cannot be separated by this character. 

 The horns vary in length, from 1 5 mm to 10 mm , 6 or 7 mm. 

 being about the average length. The beetles feed on the 

 growing heart in the crown of the coco-nut trees. They 

 usually enter the trees close to the base of a leaf, crawling 

 down as far as they can between the tree and leaf-stem 

 before beginning to bore. The spiny legs enable the 

 beetle to brace itself firmly before it begins literally to 

 root its way into the web-like sheath through which 

 it usually has to pass before it reaches the bird wood. 

 In doing this the head is lowered and the horn thus 

 thrust forward The horn becomes imbedded in the tissue 

 of the plant and when it is raised serves as an anchor to hold 

 the insect while it pulls or pushes its body forward with its 

 legs, or while it tears the tissue of the plant with its heavy 

 mandibles. The insect will always root and push its way as 

 deep as it can before it begins to bore. The amount of 

 power it can develop is truly remarkable.' 



