90 



THE AGKICULTURAL NEWS. 



Makch 11, 1916. 



INSECT NOTES. 



INSECT PESTS IN MAURITIUS. 



The Annual iJeport on the Depaitnirnt of Agricultui'e; 

 Mauritius, for 1914, contains a report on tlie work of the 

 Division of Entomology for that period from whicli tiie 

 following notes have been extracted. 



INSECT PEST OF SUG.\R-CAXE. 



The jjink borer {SemmKi nonagi ioidex), tlie spotted 

 borer {Diatraca striKtal/s), the white borer {Aryyroploce 

 schixtaceami), and the white grub LdchnostcriKi sp., which, 

 a.ssociated with the rhinoceros beetle (Orpc'es tiirandus), 

 caused serious damage to canes on a small area, where it was 

 kept under control. 



The pink borer caused injury to 'virgin' (plant) canes in 

 damp localities. Satisfactory results in its control have been 

 •obtained by tlie use of maize as a trap crop. An efficient egg 

 •parasite {Ci'ruf.hron henciicieinf) has now been discovered in 

 the island. Tlie eggs of the pink borer are conspicuous and 

 easily collected, and by selecting and saving from destruction 

 the parasitized eggs, it is e.xpeeted to increase the efficiency of 

 this useful insect. 



PESTS OF J'OEEST TREES. 



The insects recorded as attacking forest trees were three 

 in number: a pyralid moth severely attacked young plantations 

 of mahogany trees; 'illipe' trees suffered much from attacks 

 of a longicorn beetle {I helematium fenionile), and 'Bois Noir' 

 {Alhiv:ia Lehhek) was again reported as being badly attacked 

 by BatDcera rubrn. (This is of interest in connexion with the 

 recent appearance of this insect in the West Indies, where 

 Alihda Lehhek is of common occurrence, (ste Arpiru/lura/ 

 Neivs for February 26, 1916). 



A considerable number of pests were reported as CJarden 

 Pests; these are mostly of little interest in the West Indies. 



The insects affecting stored grains were dealt with in 

 a separate bulletin 



Under the heading of Leguminous Crops, the 'Pois sabre' 

 borer (Argi/roplore rliyririns) was recorded as having been 

 very destructive, and causing the wholesale destruction of 

 several fields oi the crop. It may be possible to control this 

 pest by hand picking the eggs. 



INSECTS .\TTACKIN(; DOMESTIC ANI.MALS. 



The poultry Hea (Sarcoji^i/lla gallimice'i). In a poultry 

 run infested by this pest, spraying with kerosene and Phenyl 

 mixture at 1 per cent, was successful in controlling the pest. 



The ticks were thoroughly investigated, specimens 

 were received from all parts of the islmd resulting in the 

 identification of six species. The host distribution was as 

 follows: — 



Amiyi>mnia vitriegatwii, on deer, cattle and goats. 



Bhi2>iiepk'iJus sanguineus on ca.tt\e and dogs. 



evertm „ „ 



Miiygmopui ninulutux, var. decolitratus on cattle. 



Amhlyoiiinvi sp. on cattle. 



Argas jiei sicus on fowls. 



Three of these species, Rh. ei/erfxi, Rh. aniigiiinem^ and 

 M. (ini)'ulittiix, var. i/er/m ntu.i, a.re the well-known carriers of 

 dog and cattle piroplasmosis (jaundice and red-water fever). 



A dipping tank has been erected during the year on one 

 estate. The results have been most satisfactory. Ticks have 

 decreased in numbers, and the general condition of the cattle 

 has improved. 



THE BROWN IIARI" liACK (Fhytnlux xinithi). 



'I'his insect continued to be captured and collected in 

 enormous numbers, the total number of beetles being 



38,816,417, and of larvae 6,694,300, making a grand total of 

 beetles and grubs of 45,.510 717. 



In spite of the increasing numbers of this insect destroyed 

 from year to year the infested area is not found to be 

 increasing. It is stated, however, that more stringent 

 measures against this pest will have to be taken in the near 

 future, and infested estates will have to be called upon for 

 further a.ssistance in the campaign. 



Another consigment of Tkiphin p'lmlMa was received 

 from Barbados, but no parasitized Phytalus larvae had been 

 found in the field. 



RATS. 



Specimens of a rat have Ijeen received from .Mr. W. R. 

 Forrest in Antigua, and these were submitted to the 

 authorities at the P.ritish JIuseum, Natural History, by whom 

 they were identified. 



The note accompanying the first specimen was as 

 follows: 'I send a specimen which I take to be a mature 

 species; it is called by some a rat by others a mouse. It 

 seems to be very common in town (St. Johns), lives in holes 

 in mason work, etc' 



In a letter recently received from I)r. G. .V. K. Marshall, 

 Director of the Imperial Jiureau of Entomology, through 

 whom the material was forwarded for identification, it is 

 stated that the specimens represent the common black rat 

 (Epimys [Mus] rattux) while the larger rat which was 

 referred to as al.so being common in St. Johns is probably the 

 brown rat Mux tiorrei/iciis =(Mti.< decunianus). 



The Cambridge Natural History (Mammals, p. 472) 

 states in regard to these two species: 'The black rat (.1/. rat- 

 tus) is like a large mouse, and is smaller and blacker in 

 colour than "the Hanoverian rat". It is sometimes called the 

 Old English rat, but seems nevertheless to be not a truly 

 indigenous rodent. It has been so defeated by competition 

 with the Hanoverian rat that it is now not a common 

 species in this country (England). 



'The Hanoverian or brown rat (M. decumanus) is a larger 

 and browner animal than the last. It is verj' widely distri- 

 buted through the globe, no doubt on account of the fact 

 that it is readily transported by man. . . . The original 

 home of the brown rat is thought by Dr. Ulanford to be 

 Mongolia. There is so far a justification for the name 

 Hanoverian rat that the animal reached this country (England) 

 about the year 172S. But tliere seems to be no reason for 

 calling it, as is sometinies done, the Norwaj- rat.' 



It would appear that the black rat whether indigenous 

 to the American t'ontinents and islands or notwasto.be 

 found in the New World previous to the advent of the brown 

 rat. It is known that in many localities the black rat has 

 been completely driven out or exterminated by the larger and 

 more ferocious brown species. 



The occurrence of both species commonly in the same 

 town, as at St. Johns, Antigua, may intlicate that in this 

 instance the brown rat Is of fairly recent introduction, and that 

 for some reasf)n or other the black rat has been better able to 

 maintain its numbers than it has in certain other .situations. 



In Barbados, both species are present, the brown rat 

 being the more abundant, occurring throughout the island, 

 living in buildings, in trees, and in cane fields, where at times 

 it is responsible for a considemble amount of injury to the 

 sugar cane plants. The black rat appears not to be of 

 common occurrence in sugar-cane fields, in Barbados. 



