20 THE SUGAR-CANE INSECTS OF HAWAII. 
FACTORS RESPONSIBLE FOR THE OUTBREAK OF 1903. 
On those plantations where the outbreak of the leafhoppers became 
epidemic the writer made careful observations to determine, if pos- 
sible, the conditions of season, soil, varieties, or methods of cultiva- 
tion which might have contributed to the leafhopper development. 
Some of these conditions noted will be mentioned. _. 
(1) The season during which the attack was most serious was not 
the growing season, and in some localities the weather was most 
unfavorable for the growth of the cane. In one instance, for example, 
there were during one month 24 rainy days out of the 30; and since 
the temperature on a rainy day is some ten degrees lower than on a 
bright day, and because of the absence of sunshine to carry on the 
work of assimilation, a less vigorous growth of cane resulted. 
(2) The long duration of prevailing high winds. 
(3) An impoverished condition of the soil. Certain fields in which 
the leafhopper was epidemic had been planted continuously to cane 
for over 20 years. The soil in certain parts of some fields, also, 
where the leafhopper infestation was greatest was found to be in poor 
condition because of lack of drainage. 
(4) As the rainy season was followed by a long period of dry weather, 
without the means of irrigation, the cane lacked sufficient moisture 
to enable it to put forth a vigorous growth. This point was demon- 
strated on an unirrigated plantation in the district of Kohala, Hawaii. 
A portion of a field was seriously attacked by the leafhopper during 
the month of September, 1903, after several months of dry weather. 
The manager of the plantation, Mr. E. E. Olding, was able to run 
water into this portion of the field and irrigated the cane four times 
at intervals of about a week, with the result that the cane, although 
showing the attack in the smallness of the joints grown during that 
time, recovered, and when the writer visited the field during the 
month of November of the same year was, in appearance, not unlike 
healthy portions of the same field. 
(5) The presence of other pests, principally the cane borer (Sphen- 
ophorus obscurus) and the leaf-roller (Omiodes accepta). 
(6) The lack of thorough cultivation. 
(7) The injury to cane on the makai (seaward) fields by the salt 
spray or the check to the cane by the cold on the mauka (mountain- 
ward) fields. 
(8) The deterioration of varieties. 
(9) The complications due to the presence of certain diseases. 
THE LEAFHOPPER AND BEEKEEPING. 
An interesting condition of affairs arising from the leafhopper 
attack on sugar cane is the collection of the honeydew by honey bees. 
The increase in the production of Hawaiian honey of recent years 
