232 



TROPICAL AGRICULTURE 



CHAP. 



Insecticides, scale blight, Coccus, and the mite, Acarus. Should these 

 pests appear to injure the trees, they may be killed by apply- 

 ing lime wash, or kerosine oil emulsion, to the affected stems 

 with a brush. 



Returns. 



The 

 markets. 



Varieties. CROPS. There are two principal kinds of castor oil seeds 

 cultivated the large and the small varieties. The large seeds 

 yield from 25 to 30 per cent, of oil, but the oil is of an in- 

 ferior quality, and it is used only for lighting and lubricating 



The oil. purposes. The small seeds give from 38 to 40 per cent, of 

 oil, which is of a finer quality, and this variety is the one 

 from which the medicinal cold-drawn oil is obtained. The 

 plants commence to bear at the fourth month, and the crops 

 will become larger as the trees increase in size. In India, 

 sometimes a yield of 1 5 Ibs. of seed is obtained from single 

 trees ; and, in the United States, it is reckoned that from 

 fifteen to twenty-five bushels are got from an acre of land 

 under castor seed cultivation. There is a ready sale for the 

 cleaned seed in the American and European markets. In 

 the United States, the seeds are sold by the bushel of 46 Ibs., 

 and the produce may be shipped m bags or in barrels. 



In harvesting, the spikes are gathered as soon as the cap- 

 sules commence to turn brown ; for, if they were left on the 

 trees to ripen thoroughly, the crops would be lost as the cap- 

 sules burst open suddenly with some force and scatter the 

 seed to wide distances. The spikes, when cut off, are carried 

 to the drying house, or they may be exposed to the sun on 

 barbecues. During the day the spikes are turned over with 

 a rake once or twice, so as to allow the lower layers to 

 receive the rays of the sun. In from three to four days all 



Winnowing, the capsules will have burst, and then the seeds may be 

 cleaned from the husks and foreign matter by winnowing. 

 Should rain come on whilst the spikes are exposed out of 

 doors, they should be raked into heaps, and covered up with 

 tarpaulins, or boards. As the seeds " pop " to some distance 

 it is usual to confine the drying-place by a board fence four 



The seeds 

 dried in the 

 sun. 



