164 H. A. TEMPANY AND D. d'eMMEREZ DE CHARMOY. 



The Introduction of a Natural Parasitic Enemy of the Pest. 



The identification by Nowell, in 1912, of Tij)hia parallela as the principal insect 

 enemy of Ph/jtalus smiihi in Barbados led to a series of attempts being made between 

 the years 1913-1915 to introduce the insect into Mamitius. A full account of the 

 efforts made in this direction are contained in the paper on this subject previously 

 referred to, published in the Bulletin of Entomological Research. 



Since the pubhcation of the papei' in question TipJiia parallela has estabhshed 

 itself firmly at several points in the infested zone and at these points has already 

 exercised a very marked influence on the incidence of the pest. The effect was first 

 seen in 1917 at Esperance estate, where, as the result of the action of the parasite, 

 the total number of adult insects captured in the season 1917-1918 showed a very 

 marked reduction over that of the previous year, the reduction being still more 

 marked in the year 1918-1919. In the year 1918-1919 similar reductions became 

 visible in the case of Maison Blanche estate and also on the group of small properties 

 classed mider the head '' Small Planters " which occur in this vicinity. During 

 the present season, though completed figures are not available, there is evidence 

 to show that a similar reduction has become evident at Beau Plan Estate ; while 

 at Esperance where the insects were formerly present in great numbers they are 

 now only met with occasionally. 



The following figures for the number of insects captured at these points during 

 the years 1916-17, 1917-18 and 1918-19 illustrate these remarks : — 



Year Esperance Maison Blanche Small Planters 



1916-17 21,419,586 — — 



1917-18 7,650,461 1,895,752 8,322,130 



1918-19 518,320 937,950 4,303,625 



The spread of Tiphia throughout the infested area has been systematically 

 assisted by the liberation of insects in places where they did not previously exist. 

 An important point, which has materially assisted in the dissemination of the insects, 

 is the existence of the wild plant Cordia interrupta (Herbe Conde), the sweetish 

 exudation from the leaves of which provides food for the Tiphia adults. It is also 

 noteworthy that the plant attracts Phytalus ; in consequence planters are now 

 growing the Cordia around the borders of the cane-fields, and this has materially 

 facihtated both the capture of Phytalus and the dissemination of Tiphia. 



Legislative Measures. 



Legislative measures for the control of plant pests and diseases are provided 

 under Ordinance No. 8 of 1911. 



This ordinance provides for the proclamation of any prescribed area as being 

 infected with plant disease, including both insect and fungous pests, and for the 

 making of general or special orders for the following purposes : — 



(a) for prescribing or regulating the destruction, removal, uprooting, disposal 

 or treatment of plants and products of a vegetable nature within an infected 

 district, area or place ; 

 (6) for prescribing or regulating the cleansing and disinfecting of infected 



places or areas, or parts thereof ; 

 (c) for prescribing the period within w^hich it will not.be lawful to plant or 

 replant with any plant whatsoever, or with any particular kind of plant, 

 the whole or any portion of an infected district, area or place ; 



