6 
cent of the plants in another 10-acre field are now affected the same 
way. Several fields of 1 or 2 acres with the same symptoms have 
been lost, and numerous cases of a few hundred plants showing this 
peculiar chlorosis have been observed in different plantations. 
The places where the chlorotic plants occurred were not confined to 
any one district of the island or to any one physical type of soil. 
APPEARANCE OF PLANTS ON UNSUITABLE SOILS. 
The degree to which the plants were affected and the age of the 
plants when the bleaching first manifested itself varied somewhat in 
the different instances. In some places many plants became almost 
ivory white, apparently without a vestige of chlorophyll; later the 
leaves of such plants showed brown spots and the plants finally 
decayed. In other cases the leaves were a yellowish white, with red 
streaks and small patches of green. Sometimes the outer leaves 
remained a light green while the new heart leaves were creamy white. 
In other cases the leaves were for many months practically normal 
in color, but gradually light spots appeared, producing a mottled 
appearance, and finally, in 14 or 15 months, the leaves bleached out to 
a uniform greenish yellow. The lack of chlorophyll, or chlorosis, 
was generally very pronounced when the plant was 9 months old, 
though sometimes it appeared in 3 or 4 months, and sometimes it did 
not appear until the plant was 15 or 16 months old. 
The root system of the chlorotic plants showed no evidence of 
disease. The roots differed from those of normal plants in being 
somewhat longer and not so thick; they were more like those of plants 
suffering from starvation. The plants, however, that had suffered 
from the chlorosis for some time had many dead roots, but the func- 
tioning roots appeared to be perfectly healthy and on examination by 
the pathologist failed to show any bacterial or fungus trouble. 
PRELIMINARY INVESTIGATIONS. 
From the fact that the first examples of the chlorosis appeared in 
plantations near the sea it was thought by some that the trouble was 
caused by sea spray being blown in on the plants. This was shown 
not to be the case, however, as on some plantations within less than 
a hundred yards of the sea the plants were perfectly green and 
healthy and later the distinctive chlorosis was observed on planta- 
tions several miles from the coast; moreover, plants heavily sprayed 
with sea water for four consecutive days showed no injury. 
It was also thought that the chlorosis might be attributed to lack of 
aeration of the roots from poor drainage. In some places where the 
chlorosis occurred the drainage was poor, and in the spots of poorest 
drainage the chlorosis was most intense. In other places, however, 
[Bull. 11] 
