EDIBLE CANNA IN HAWAII 7 
kept in the field in good condition for one month when they are 
stacked in heaps not over 2 feet high and are covered with canna 
tops. In two months' time, the tubers that are nearest the ground 
will have started to germinate. 
INSECTS AND DISEASES 
This plant is remarkably free from both insect pests and plant 
diseases. Grasshoppers and Japanese beetles are occasionally 
found feeding on the foliage when more desirable host plants are 
not available, but their damage is negligible. In Waimea, Hawaii, 
cutworms are the most destructive pests of canna. Their injuries 
in certain seasons are confined to the tender young shoots which 
are either devoured or completely cut off at the base of the growing 
plant. The following poison baits are recommended as control 
measures: 
Paris-green-bran mash. — Thoroughly mix 25 pounds of bran with one-half pound 
of Paris green. Add to the mixture 6 finely chopped lemons or 1 quart of cheap 
molasses. Stir well, and add sufficient water to moisten. Do not make the 
mixture so thin that it can not be easily and economically distributed. 
Small patches should be treated with 1 ounce of Paris green to 3 pounds of 
bran, and one-half cup of molasses. Four to six times as much by weight of 
arsenate of lead should be used as in case of the Paris green, and only half as 
much white arsenic. 
Poisoned succulent foliage.— Fresh cut alfalfa or other succulent foliage which 
is attractive to the insects may be sprayed with Paris green or arsenate of lead 
mixtures, and the poisoned leaves and stems scattered in the infested fields. 
Criddle mixture. — Large areas may be treated with fresh horse dung, salt, 
and Paris green, in the proportions of 60, 2, and 1 pounds, respectively, per acre. 
This mixture is equally as effective and not as expensive as bran. The Paris 
green should be stirred into enough water to form a thin paste and then 
thoroughly mixed with the manure. Five pounds of arsenate of lead, or one- 
half pound of white arsenic, may be used instead of the Paris green. 
Rats, which occasionally gnaw young tubers, can be brought 
under control by the use of traps and poisoned bait. 
A field of canna will sometimes present a burned appearance in 
the dry season, due to the drying effect of hot winds. 
COMPOSITION 
In two analyses made at the station, edible canna was found to 
vary in water content from 65.86 to 81.58 per cent, and in nitrogen- 
free extract from 15.57 to 31.34 per cent. 9 The other constituents 
showed corresponding differences when expressed as percentages of 
dry material. 
In making a study of the value of the crop as a feed and as a 
commercial source of starch, it is obviously necessary that determina- 
tion be made of its average chemical composition and of the varia- 
tion- which take place. This is particularly important in case of 
the edible canna, which has no regular period for maturing and 
continues to grow indefinitely. On this account there has been a 
great difference of opinion as to the best age at which to harvest the 
tubers for maximum starch production. In some cases the crop is 
harvested after a growing period of 6 months, while in others it is 
allowed to grow for 18 months or more. Crops which differ so greatly 
in age would probably have appreciable differences in composition. 
•Hawaii Sta. Press Bui. 53, p. 9. ♦ 
