46 



is raised under optimum conditions of rainfall, soil fertility, and 

 cultivation. 



The rainfall on the Oahu sisal lands is about 30 inches per 

 annum. No artificial irrigation is undertaken as there is no 

 available water. Despite the popular impression that sisal has 

 very low water requirements, it is unquestionably true that this 

 crop will respond generously to increased water supply. If 

 water could be obtained at low cost the increased yield of fibre 

 would probably more than pay for the expense of irrigation, 

 and the life of the plant lengthened. There seems to be prac- 

 tically no data concerning the response of sisal to irrigation. 



Hawaiian sisal is notably free from insect pests and fungus 

 diseases. The plants are uniformly clean and sound, and their 

 life is terminated only by their own physiological boundaries. 

 Occasionally, through carelessness or misfortune, a fire gets 

 started in the dry weeds and brush between the rows. This 

 ruins all of the sisal plants with which it comes in contact. Fires 

 of this kind are counted among the most serious enemies of sisal. 



Sisal leaves do not drop ofif or separate themselves from the 

 parent plant. Normally, upon maturity, they droop groundward 

 and become dry, leathery, and shrivelled. When the whole plant 

 finally dies it remains in situ for. a number of years, a mass of 

 debris, surrounded by offshoots in various stages of development. 



Two wholly distinct sets of structures for vegetative reproduc- 

 tion are produced by the sisal plant, — ofifshoots and bulbils. The 

 ofifshoots or suckers (rhizomes) are formed after the first or 

 second year in the field and their production continues until 

 the death of the plant. Bulbils ("pole" or "mast" plants) are 

 formed only upon the pole or scape, and thus come only once 

 in the fife-history of the plant, just prior to its death. The ofi:'- 

 shoots develop from the roots and come up through the soil in 

 the immediate vicinity of the parent plants, although sometimes 

 at a distance of 6-12 feet. There are usually 6-18 offshoots 

 around a mature sisal plant. The aerial portion is 8-24 inches 

 high, and is a miniature rosette, resembling the parent plant. It 

 obtains food not only from its own roots, but also from the 

 runner from the parent plant. These suckers correspond in 

 structure and function to the suckers that occur on such other 

 tropical plants as the taro, date palm, pineapple plant, banana, 

 etc. 



The bulbils are formed on the branches of the pole, after the 

 flowers have fallen. One to four thousand bulbils are borne 

 upon a single pole. The bulbils are 1-6 inches long, and com- 

 prise several fleshy leaves upon a short stem. They fall to the 

 ground and root and may be gathered for propagation. Bulbils 

 are not as good as offshoots, however, as they require 1-2 years 

 in a nursery before they are suitable for planting out in the 

 fields. When about 1 ft. high the nursery plants are dug, all 

 the roots and about half of the leaves are cut off, and the plants 



