THE CAMPAIGx^J AGAINST PHYTALUS SMITHI. 161 



It would appear that climate is a most important factor in the control of the 

 pest ; to exemplify this it may be stated that the insect was first detected in the year 

 1907 at Reduit at an elevation of 1,100 feet, where the climate is distinctly cooler 

 than at Pamplemousses. The insect has been kept under close observation at thi ? 

 point for a number of years past and has not up to the present shown any signs of 

 becoming a serious pest. In this connection mention may be made of the very 

 recent discovery of the beetle on a small area at Joli Bois in the Savanne district of 

 the island at an elevation of about 900 feet. At this particular point it seems probable 

 that the insect was introduced from Pamplemousses in planting materials trans- 

 ported from forest nurseries formerly existing in Pamplemousses Gardens, for the 

 purpose of restocking Government forests adjacent to this point. No planting 

 material has been sent out from these nurseries since the discovery of the pest at 

 Pamplemousses in 1911, but just prior to this, important consignments of such 

 materials were delivered at Riviere du Poste Railway Station, which is in the centre 

 of the infested zone and undoubtedly is the focus from which the infestation 

 originated. The fact that during an interval of eight years the pest has extended 

 only to an insignificant extent is further evidence of the eSect of climate on its 

 incidence. 



The extent of the infested area in the Pamplemousses district now measures 

 approximately twelve square miles. When the pest was first detected in 1911, the 

 infested area measured only three square miles, the increase in the intervening period 

 being due to outward spread. Energetic measures, described in a later section of 

 this paper, are now being taken with a view to circumscribing its further extension. 

 The Royal Botanical Gardens are approximately in the centre of the infested zone 

 and are apparently the nucleus from which infestation originally started. 



Remedial Measures. 



The remedial measures that have been applied to combat the pest may be grouped 

 under the followino heads : — 



{a) the collection and destruction of adult insects on emergence ; 

 (6) the digging out and destruction of larvae in badly infected fields ; 

 (c) census and survey work designed to ascertain the location and distribution 

 of foci of infestation throughout the infested area ; 



{(l) the introduction and dissemination of the natural parasitic enemies of the 



pest ; 



(e) legislative measures directed towards preventing the spread of the pest to 

 uninfested regions, and affording the necessary powers to the authorities 

 to carry out protective and destructive work in infested areas ; 

 (/) experimental work on other possible means of control. 

 The control work in the Pamplemousses area has assumed very considerable 

 proportions, and the local headquarters for dealing with the work have for some 

 years been estabhshed in the Royal Botanical Gardens. In the following parag 'aphs 

 an account is given of the administrative and practical methods employed under 

 each of the above sub-heads, after which information is supplied concerning the 

 results of the work. 

 (673) e2 



