THE SUGAR-CANE LEAFHOPPER. 23 
and burning over of those centers in the fields where the species had 
become numerous. In this practice it was observed that many of 
the adults were able to take flight from the burning cane and escape 
to adjoining fields. However, many adults and all of the unhatched 
eggs in the leaves and the immature wingless forms were destroyed. 
The center of infestation was destroyed, and this gave the ratoon 
crop over these areas a chance under more favorable conditions. 
Stripping the leaves——For agricultural reasons it was a common 
practice in Hawaii to strip the lower mature leaves from the cane 
stalk. It was believed at first that this operation would greatly 
lessen the numbers of the leafhopper by the exposure of the un- 
hatched forms in the leaves of the cane and by removing a place of 
shelter for the active forms. Observations made during the summer 
months indicated that stripping was beneficial from the standpoint 
of the control of the leafhopper. Later observations made during 
the winter months, however, when growth of the cane practically 
ceases, showed a very serious condition of affairs, namely, that in 
heavy infestation the internodes of the stalk of stripped cane con- 
tained hundreds of punctures from egg laying, while the internodes 
of unstripped cane were protected from such injury by the leaf- 
sheaths. 
Burning of trash after harvestrng.—The thorough burning of the 
trash after the cane is harvested is the most effective method prac- 
ticed for the control of the insects of sugar cane. In the case of 
the leafhopper many of the adults no doubt take flight, but the 
destruction to the eggs and immature forms in the trash is enormous. 
The place where the greatest numbers of the leafhopper were noted 
in 1903 was on a plantation where the practice of ‘‘burning off” 
had been discontinued for several years, and the manager attributed 
the unusual increase of the pest to the fact that the trash had not 
been burned. Both for the leafhopper and the cane borer, burning off 
has become general once more. 
INDIRECT MEASURES. 
PREVENTIVE METHODS. 
Selection of varieties of cane for planting.—There was noticeable 
in general throughout the plantations a marked difference in the 
power of the different varieties to resist the attack of the leafhopper. 
While the same variety would vary in different localities as regards 
growth and resistance, still the difference between any two varieties 
remained constant. For example, Yellow Caledonia was invariably 
the more resistant as compared to Rose Bamboo and Lahaina, and 
while the former was more seriously attacked in some localities than 
in others, wherever the opportunity offered itself for comparison with 
the latter, the Yellow Caledonia made the best showing. It is for 
