larvae per dip. Large-bulb pipettes (turkey basters) are used to remove water from
small areas such as tree holes or leaf axiIs. Larval surveys show the exact areas in
which mosquito breeding occurs and should be marked on the survey map. Larvae
surveys are of special value of guidance of control operations.
d. Adult Surveys. The adult survey permits evaluation of the incidence of
mosquitoes and shows the relative abundance of the various species at any time. Adult
mosquito surveys are conducted by the use of traps, resting station collections, and
biting or landing rates. In addition to these common survey methods, there are a
number of special procedures used in research or disease survey programs. These
are: traps baited with humans or animals, oviposition traps, carbon dioxide traps, and
large nets of various designs and constructions.
e. Light Traps. Many mosquito species are attracted to Iight. Making it possible
to utiIize this response in sampling adult populations between dusk and dawn. Three
widely used Iight traps are the New Jersey mosquito Iight trap (see figure 3-3) which
was developed in the 1930's and has been used extensively In obtaining data on the
intensity and specific composition of mosquito populations, the collapsible unit. and the
battery-powered CDC type miniature Iight trap. Of these Iight traps, the CDC miniature
Iight trap is the most versatiIe since it is more portable, Iight weight, and battery
operated. Light trap data are reported as numbers of mosquitoes per trap per night, or
simply as per trap night. The numbers per trap night are calculated by dividing the
number of mosquitoes captured by the number of traps in use then dividing by the
number of nights the traps were operated. Data from widely separated sites that
consistently differ in the numbers of mosquitoes captured should not be combined.
NEW JERSEY STYLE UNIT
COLLAPSIBLE UNIT
Figure 3-3. New Jersey type mosquito light trap.
MD0170
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