a handbook of the mosquitoes of north america - Systematic Catalog ...

MOSQUITO REDUCTION 71
Destructiovl of the Adults
Frequently the control of mosquitoes may be aided by the
destruction of the hibernating adults. The species of A120-
pheles, Culex and most Thle,obaldia, pass the winter as adults
hidden away in all sorts of shelters, particularly in houses, out-
buildings, stables, etc. A close inspection in badly infested re-
gions will locate the principal hiding places. The adults may be
destroyed by fumigating with cyanide gas, dusting with calcium
cyanide, or spraying the walls with kerosene. The use of
hydrocyanic gas in any form should be done only under the
supervision of some one familiar with its deadly properties.
The kerosene should be employed with care, due to the fire
hazards involved. The destruction of hibernating adults should
be undertaken only when excessive breeding has produced such
numbers that a systematic clean-up in restricted areas seems
warranted. The most efficient method is an educational one-
teach everyone the importance of destroying all adults during
the winter.
Mosquitoes have many natural enemies, both as predators
and parasites. Certain species of birds, bats, and insects prey
upon them but their effectiveness in reducing the mosquito
population does not appear very marked. Many species of
fish feed on the larvae and certain top-feeding minnows, par-
ticularly of the genus Gambzrsia,2 have been extensively em-
ployed in many parts of the world. Though undoubtedly fishes
play an important part in mosquito reduction and the utiliza-
tion of certain species is highly to be commended, yet adequate
control cannot be obtained by them alone unless the conditions
are more or less ideal from the standpoint of the fishes em-
ployed. In any plan to use fishes in a control area, the best pos-
sible scientific advice should be obtained. The effectiveness of
the fishes depend on conditions which bring about their rapid
2 For an extended and excellent account consult, Hildebrand, “A
Study of the Top Minnow,” U. S. Pub. Health Bull. No. 153, 1925.
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