BANANA CULTURE IN HAWAII 23 
the plant as they ripened, were found not to be infested, although 
growing in the midst of many other species of fruits. Five hundred 
overripe fruits of Manila hemp or abaca (Musa textilis) and 60 
ripe fruits of Borabora bananas (J/, fehi) growing in the mountain 
gorges at the head of Manoa Valley, Oahu, were found to be free 
from infestation. 
A number of experiments have been conducted in both the field and 
laboratory to learn why bananas are immune from attack by the 
Mediterranean fruit fly. It was lon<r thought that the fruit was 
afforded protection by other plants for which the fly had a pref- 
erence. Results of experiments failed to confirm this belief, however. 
When attempts failed to force the female fly to oviposit in bananas 
that were sufficiently mature to ship, freshly laid eggs were taken 
from another kind of fruit and placed in incisions made in the 
banana, each bunch of which was marked. Some of the eggs hatched, 
but the larvae died before entering the pulp. 
During the 13 years the local representatives of the Federal De- 
partment of Agriculture have supervised the inspection of bananas 
for shipment no fruit fly infestation has been discovered among either 
green or ripe bananas grown under normal field conditions. 
The freckle disease (Phoma mus(e), the most serious known to 
local banana growers, was described by Carpenter in 1918 (7, p. 36). 
The disease attacks almost exclusively the Chinese banana, but has 
also been observed on the foliage and fruit of the Lady Finger and 
Father Leonore varieties. The disease does the most damage during 
the months of greatest moisture. The earlier stages of growth and 
spore production of the fungus take place in the tissues of the foliage. 
Later the spores fall upon bunches of fruit which are approaching 
maturity and cause the skin to blacken in specks or freckles. The 
freckles usually occur mainly on the fruit of the upper part of the 
bunch. Damage lies largely in the spotted appearance of the skin 
and becomes more evident as the fruit ripens and attains full color. 
The disease is largely controlled by spraying with Bordeaux mixture 
and by wrapping the bunch of fruit, several weeks before it reaches 
full size, with newspapers or with a tough paper slip which is manu- 
factured for the purpose. It is important that the wrapper com- 
pletely cover the upper part of the bunch. 
The tree rat (Mils rattus), sometimes called the black rat or the 
blue rat. climbs up on the banana plant and eats part of the matur- 
ing fruits. Although it seldom seriously damages commercial fields 
where the fruit is picked green for shipment, it does considerable 
injury to bananas growing in gardens or wild in the mountains, 
where the fruit naturally ripens on the plants. The tree rat is easily 
identified by its long, slender snout, large ears, and body of dark 
bluish color; it nests usually in the tree tops and occasionally in 
hidden places on the ground. The rat feeds upon many kinds of 
fruits and nuts, and has a particular liking for coconuts, bananas, and 
algaroba beans. The pest is best controlled by shooting, using light 
charges of small shot. 
