32 
1890 a few isolated spots were known to be affected, and from 
these the spread of the disease can be traced. 
In Panama at least 15,000 to 20,000 acres of banana plantations 
have been abandoned and many thousands more are seriously af- 
fected, while in Costa Rica the damage has been even greater, so 
that it is safe to estimate at least $2,000,000 capital loss in these 
two regions in the last five years. 
Young and old plantations are attacked with equal intensity. 
Plants are also attacked on various soils — sands, clay, etc. The 
disease seldom becomes evident until the shoots have reached a 
height of four to six feet at the collar (point the leaves diverge). 
Commonly the first external sign is a rapid yellowish and subse- 
quent browning and wilting of one or more leaves. Sometimes 
there is a striking curvature and yellowing of the terminal part 
of the leaf-blade, while the remainder is still green. Eventually 
all the leaves die and fall back against the trunk, leaving a crop 
of suckers which in turn are killed and give place to still weaker 
shoots. The fruit of diseased shoots rarely matures, and even 
when mature is worthless with blotched, somewhat shrivelled 
surface and dry, pithy interior. Shoots which develop after one 
or two suckers have died rarely reach the flowering stage. 
When they do, however, weak, distorted, worthless bunches are 
produced. 
On cutting the pseudo-stem across and longitudinally many of 
the bundles are found to be of a yellow, reddish or reddish pur- 
ple color, the color deepening toward the root-stock. In the 
last stages the color of the bundles may be almost black. While 
in recently affected plants, the vessels o? the upper part of the 
stalk and the leaves may be normal, those of the root-stock are 
always colored. In most cases the thin partitions separating 
the air chambers are wrinkled and collapsed. The juice of dis- 
eased plants contains much less tannin than that of normal plants. 
A nauseating odor is often given off when leaf-stalks which 
have been diseased for some time are cut open, though there may 
be no sign of rotting in the trunk. 
It has been proved that the disease is not due to local condi- 
tions such as too wet or too dry soil, etc., yet some of these condi- 
tions may prejudice the plants to the disease. There is a sea- 
sonal periodicity in the activity of the blight corresponding to 
the periodicity of growth in the banana plants. It is during the 
stage of most rapid growth that the plants most easily succumb, 
particularly from April to July. In periods of less active growth 
many plants seem to recover, but only to die during the next 
season of rapid growth. Neither drainage nor improved methods 
of cultivation and pruning have checked the disease. Indeed, 
increased fertilization seems to make it more virulent. There is 
no evidence that insects are in any way responsible for the 
trouble. 
ATicroscopic examination of the stained vascular Inmdles 
