INSECT PESTS IN MAURITIUS. 187 



Coconut. 



This plant thrives in the coastal regions wherever the land is not rocky. A certain 

 amount of extension is being given to its cultivation in certain parts of the coastal 

 belt, and promising results are being obtained. 



The beetle, Oryctes tarandus, Oliv., occasionally bores into the tender part of the 

 stem, which it usually enters beneath the basal part of a leaf, just where it begins to 

 stretch away from the stem, and bores a gallery right through. It also bores its 

 way into the mid-rib of the leaf. The galleries in the stem are usually made 

 tangentially, and in such cases, though the tree is not immediately affected thereby, 

 a door is opened for bud-rot. It often happens, however, that the beetle bores its 

 way radially inwards into the growing point ; in such a case the health of the palm 

 is affected and immediate death results. 



Of all the scales which are found on the coconut palm, the most common is 

 Diaspis boisduvali, Sign. It occurs m very great numbers all over the island and 

 is a serious pest. The injury done is very great both to old and young plants, the 

 insect occurring in thousands on a single leaf. Now that a certain extension is being 

 given to the cultivation of the coconut, combative measures will have to be adopted, 

 as the pest is a serious menace to the future of the coconut industry. 



Coffee. 



Coffee was extensively grown years ago, but its cultivation has had to be aban- 

 doned on account of the attacks of leaf disease {Hemileia vastatrix). It is, however, 

 cultivated in certain localities for local consumption. Liberian coffee thrives in 

 the colder districts and yields heavily, and if its cultivation is extended good results 

 may be expected, as it is very slightly subject to attacks of Hemileia. 



Cratopus punctum, Boh. Arabian coffee does not suffer much from the attacks 

 of this weevil, which has a marked preference for the Liberian variety, the leaves 

 of which it devours to such an extent as to cause almost entire defoliation of the 

 plant. It is worth noting that in the upland regions the attacks of Cratopus are 

 not serious. 



Adoretus versulus, Har., is another leaf pest. 



Boiys octogiittatus* The caterpillar feeds in the berry and is rather a serious 

 pest. 



Prodenia litura, F., destroys many seedling plants as they come up. 



Saissetia nigra, Nietn., and Saissetia hemisphaerica, Targ., occur as minor pests. 



Coccus viridis, Green, is sometimes found abundantly on the leaves of young 

 plants in nurseries. Infestation begins as soon as the first leaves are fully developed 

 and soon extends to the young leaves as these emerge from the bud stage. In such 

 cases the young plants soon die. The insect also occurs in abundance on older 

 plants, being the most important scale pest. 



A small Bostrychid beetle tunnels into the twigs of the coffee plant. The galleries 

 are bored obliquely to a length of 2 to 3 cm., reaching the pith. The attacks are 

 sometimes so bad as to cause the drying up of the infested twigs. 



Limes and other Citrus Fruits. 



The lime {Citrus medica var. acida) thrives in many parts of the island, especially 

 in the hotter coastal regions. The crop forms the subject of a small trade on the 

 local market, but is not of sufficient size to be dealt with on an export basis. Experi- 

 mental trials are being made at present by the Department of Agriculture with a 

 view to extending the cultivation of this plant, and it is hoped that before long lime 



* [Possibly intended for Thliptoceras octoguttalis , Feld. — Ed.] 

 (3442) o 2 



