6 BULLETIN !M6, U. S. DEPARTMENT OF AGRICULTURE. 
The "dead hearts " due to the moth borer are caused in the fol- 
lowing manner: The adult moths emerge in the spring, when the 
cane plants are small, and deposit clusters of eggs on the leaves of 
the young plants. The eggs hatch, and the small larvae feed here 
and there on the tender whorls, rolls of holes appearing on the leaves 
as they exj)and. Many of the larva? seem to perish during this 
period, partly because of their cannibalistic habits. Not more than 
three larva 3 , usually only one, seem to find their way to the interior 
of a young cane plant. When about half grown a larva crawls down 
the outside of the stem to a point near or even below the surface of 
the ground. Gnawing a hole through the outer layer of the stem it 
works its way to the interior of the plant, cutting the tender inner 
shoot and forming a " dead heart/' The inner shoot does not dry 
up immediately, so that the larva has some time to work before the 
injury can be noticed. Tunneling within the plant the insect reaches 
its largest size, pupates, and finally leaves the plant as an adult moth. 
During a year when few plants were killed in this way it was 
estimated that there were about 10 " dead hearts " per acre. In other 
years as many as 100 " dead hearts " have been counted per acre. 
EFFECT ON MATURE CANE. 
While the work of the larva? on the small plants kills the plants, 
larger stalks usually do not die. In these the larva? burrow up and 
down, sometimes gnawing their way out through the hard rind and 
reentering at another point. Frequently a mature stalk will harbor 
two or three larva? which work in different parts of the cane from the 
top to the bottom. Three sections of infested cane are illustrated in 
the frontispiece. 
A red coloration, showing dark in the canes illustrated in the fron- 
tispiece, usually is observed in the pith along the tunnels. This is the 
disease " red rot," which is caused by the fungus Collet otrichum fal- 
caturrb. "By far the largest number of stalks become infected [with 
red rot] through the burrows made by the cane borer," writes Dr. 
C. W. Edgerton (50). who sums up the injury due to red rot as 
follows : " First, the loss in stand ; second, the killing of the young 
plants; third, the injury to the leaves; fourth, 'the loss in per cent 
of sucrose with a corresponding increase of glucose." "Knowing 
that a large per cent of the red-rot infection in cane is by means 
of borer channels," Dr. Edgerton continues, " a greater effort should 
be made to control the insect." 
The spores of other fungi, as well as bacteria, 1 also gain entrance 
through the borer holes. Cane badly bored is found to be hard and 
dry, making it more difficult to grind. The growth is checked, and 
1 Prof. Wru. L. Owen (119), formerly bacteriologist of the Sugar Experiment Station 
at Audubon Park, New Orleans, La., has studied and described a bacterium which he 
found in the tunnels made by the moth borer in sugar cane. He has given it the name 
of Bacillus saccharalis. 
