21,1 Cole: Manufacture of Industrial Alcohol 4] 
estate in the third harvest, each tubero handling about 500 stalks. The 
tuberos receive 7 centavos per tinaja (36 liters). This includes all work 
in preparation for harvest, but bancas and bamboos are supplied to the 
tubero. 
The only known disease of the nipa plant is absic, which 
is caused by insect attack on the leaves. Rain kills practically 
all the insects, but sometimes it is necessary to cut the infected 
leaves. 
The number of plants per hectare-—The number of plants per 
hectare varies within wide limits depending upon whether the 
swamps are cared for or overgrown, the former condition 
naturally giving superior plants. A conservative estimate for 
cultivated nipales, or nipa swamps, can be placed at 2,000 to 
2,500 palms per hectare, of which 750 can be depended upon 
to produce fruiting stalks. Intelligent care and selection of 
seed undoubtedly would raise the yield of sap and the per- 
centage of sugar in the sap. 
Yield of sap.*—The estimates of the yield of sap vary within very wide 
limits. A distiller who has had much experience in the nipales believes 
that each producing plant will average 1.25 liters daily, and a chemist at 
one time employed by one of the distillers has stated that an average plant 
will flow 50 liters during the season. 
The yield per hectare has been siteasted: by many different writers 
and distillers and it is evident from a perusal of the figures that many are 
mere guesses. The number of plants per hectare is estimated by a chemist 
in the employ of one of the distillers to be 2,500. Internal Revenue Agent 
G. A. Ruge believes the municipalities of Abulug and Pamplona in the 
Province of Cagayan to have nipales containing 4,600 plants per hectare. 
A distiller of wide experience told me that the number is 700. If this 
latter figure is taken to be 700 plants producing at the same time I have 
no doubt that it is fairly accurate for the areas controlled by his company. 
He also stated that they obtained in actual practice 438 liters per hectare 
daily during the season. This is equivalent to 78,480 liters yearly per — 
hectare, a figure quite close to my estimates. Other figures, not so reliable, 
go as high as 225,000 liters per hectare. 
It is to be remembered that while wild nipa swamps may contain 
4,000 plants per hectare, the percentage of producing plants and the 
amount of sap which each plant yields will be less than in the cultivated 
districts. In the uncultivated areas a small proportion of the trees is 
accessible; in the cultivated, the plants are thinned, and there are more 
waterways, and yet the yield of sap per hectare is greatly increased. A 
yield of 75,000 liters of tuba per hectare per year would be extremely 
satisfactory to the distillers, and I believe this amount is seldom reached 
in the best managed nipales. It should, however, be exceeded. Some 
operators obtain only 4,000 liters per hectare during a full season. 
In the year 1909 one of the largest producers obtained 8,700,000 liters 
of tuba from an estimated area of 1,000 hectares which is at the rate of 
* Gibbs, H. D., op. cit. 117. 
