36 COCONUT PLANTER'S MANUAL. 



of the north-east monsoon. The soil is a heavy loam which becomes 

 very hard during the dry weather, but is sticky, with a tendency to- 

 wards water logging, during heavy rains. The soil conditions during 

 heavy rains may become deleterious to the coconut roots and thus lead 

 to the premature dropping of the fruit. 



Climatic conditions during the north-east monsoon are favourable 

 for fungus growth, so, at this season, nut-fall as caused by pathogenic 

 organisms may be expected to be prevalent. Nut-fall, however, fre- 

 quently occurs at this time even in the absence of any causative 

 fungus. In view of the above it is suggested that heavy rainfall may 

 produce conditions of the soil adverse to the healthy growth of the 

 root system of coconut palms. This, without the intervention of any 

 pathogenic organism, may result in the abscission of immature fruits. 

 — {See also Bulletin of the Department or Agriculture, No. 53.) 



II —PESTS. 



THE RHINOCEROS OR BLACK BEETLE OP COCONUTS. 



( Oryctes rhinoceros) 



Introduction. 

 This leaflet, dealing with the Black Beetle pest, is one of the 

 series of coconut pest leaflets which are being issued by the Depart- 

 ment of Agriculture to give coconut planters full information about 

 the three most important insect pests of the coconut palm, and about 

 the measures which should be taken to control them. The leaflet on 

 the Coconut Caterpillara, nothpr important pest, and that on the 

 Red Weevil of coconuts will follow this. These three pests cause 

 serious losses to the coconut industry in many districts, and the posi- 

 tion which this crop now occupies as one of the main industries of the 

 Island makes it essentital that all coconut growers should take measures 

 to check the ravages of these three pests wherever they occur. 



Nature of the Damage. 

 The Black Beetle is one of the most important insect pests of 

 coconuts in Ceylon, and is generally prevalent wherever coconuts and 

 other palms grow. The damage is done by the beetle stage, which 

 bores in the crowns of healthy young and older bearing palms for the 

 purpose of feeding on the juice or sap which flows from the wounds 



