93 



NOTES RELATIVE TO THE IMPORTATION OF TIPHIA PARALLELA, 



SMITH, FROM BARBADOS TO MAURITIUS FOR THE CONTROL 



OF PHYTALUS SMITHI, ARROW. 



By D. d'Emmerez de Charmoy, 

 Government Entomologist, Mauritius. 



The existence in Mauritius of the Melolonthid beetle, Phytalus smithi, Arrow, was 

 detected for the first time in July 1911 on those lands of Mon Rocher Estate which 

 adjoin the Royal Botanical Gardens of Pamplemousses. It was at once suspected 

 that this new pest of the sugar-cane must have been conveyed into the Colony by some 

 shipment or other of sugar-cane cuttings from abroad, but no clue could be found as 

 to its country of origin until February 1912, when it was detected in Barbados by 

 Mr. Guy A. K. Marshall, Director of the Imperial Bureau of Entomology, who was 

 then on his way to the Agricultural Conference held at Trinidad in that year. 



The first results of the campaign against the insect were recorded in a report 

 published by the Government of Mauritius in 1912. The methods therein prescribed 

 for combating the pest are those that are still employed and consist mainly in : — 



(1) Digging out larvae by means of hoes from those fields which show an average 

 infection of 15,000 to 20,000 larvae and over per arpent. This operation is as a rule 

 carried out during the months of May to September and is extended to October in 

 very exceptional cases, for by this time of the year most of the larvae have burrowed 

 deep into the ground for their ultimate transformation. 



(2) Capturing adult insects at night from 7 to 9 p.m., which is carried out during 

 the months of November to April and sometimes until June. 



The annexed statements show the months of greatest emergence of the adult 

 insects, the number of insects destroyed from July 1911 to June 1916, and the annual 

 expenditure incurred. 



It will be noticed that a considerable reduction in the number of insects has taken 

 place in that zone which was at first most heavily infested, thus showing the 

 possibility of effectively bringing the pest under control wherever, as at Mon Rocher, 

 the prescribed measures are carried out with persistence and energy. 



From the accompanying sketch map (see page 96) it will also be seen that the 

 insects, though not increasing in numbers, have steadily gained ground during the 

 last five years, the radius of the infected zone being now greater by one kilometre. 

 The quarantine measures, however, that were imposed from the very beginning of 

 the outbreak have succeeded in localising the pest within the limits of the District 

 of Pamplemousses and in preventing its spread throughout the Colony. 



As soon as the origin of the pest was ascertained, suggestions were made relative 

 to the introduction of its natural enemies, which it was presumed might exist in the 

 country of origin. Mr. Marshall during his stay in Barbados having ascertained that 

 the insect, although distributed throughout that island, did not cause any serious 



