NAVMED P-5010-8 - Navy Medicine - U.S. Navy

8-34 CHAPTER 8. NAVY ENTOMOLOGY AND PEST CONTROL TECHNOLOGY 8-34
g. Control of Biting Midges. For these
flies, it must be determined whether the problem is
serious enough to warrant control efforts because
they are seldom completely successful. The most
effective control is obtained while they are in the
immature stages because at that time they normally
are clustered. However, for biting midges, it
is difficult to determine where breeding is occurring
because of their habit of developing in the
soil. In addition, the larvae are very small. Very
careful survey work with soil flotation methods is
necessary to demonstrate the presence of the
larvae. This procedure is tedious and, even in the
hands of experts, subject to a considerable number
of false negatives. Any serious attempt to effect
control of human biting midges must be preceded
by an extensive and careful larval survey. Where
the area supporting larval breeding can be determined,
control of larvae can be obtained by the
direct application of insecticides to the soil. This
is an expensive procedure because control must be
done on an area basis at periodic intervals to
eventually eliminate entry by adults from
surrounding uncontrolled areas. Such treatments
must be thorough and, consequently, are also
injurious to many forms of aquatic life. These
treatments may also lead to a rapid buildup of
insecticide resistant flies. Aerosol space spray
treatments against the adults, which will be
described below for blackflies and mosquitoes, is
possibly the most effective control measure
presently available for bringing relief to small
groups of people. The camp and personnel
protective measures recommended for mosquitoes
(article 8-35 and 8-47 respectively) are all equally
effective against biting midges. Their extremely
small size must be kept in mind wherever mesh or
fabric screening is to be used. In order to exclude
biting midges, 20-mesh screening is required;
however, this will seriously interfere with ventilation.
Because of this problem, insecticide treatment
of screens can provide considerable control
and relief against flies lighting on or passing
through them. A deficiency in this control method
is that the insecticide on the screen is eventually
covered with windblown dirt and dust particles.
h. Control of Blackflies (Simulium spp.).
Blackflies are effectively controlled by the
application of larvicides to the streams where the
immature forms are developing. Where only one
brood of blackflies emerges annually, a single
treatment of streams should markedly reduce the
fly population. If multiple generations are produced,
the number of treatment should correspondingly
be increased. Stream treatment should
only be initiated when necessary to protect public
health. Because of the long flight range of
blackflies and heavy population pressures adjacent
to the control area, aerosols or mist sprayers cannot
be depended upon to provide adequate control.
Although the biting rate of blackflies is usually
much lower than that of mosquitoes, personal
protective measures against them are considered to
be essential. Generally, the measures described
for protection against in-quarters mosquito bites
(see article 8-35) apply equally to blackflies.
Characteristically, blackflies crawl beneath clothing
whenever the opportunity present. Therefore,
tight-fitting cuffs and collars are important in
preventing their bites. Protective netting and
fabric must be a minimum 20 mesh per inch and
28 mesh for standard wire or fiber.
i. Control of Horse and Deer Flies
(Tabanus spp. and Chrysops spp.). Control of
these pests is difficult and frequently ineffective.
Space applications of insecticides similar to those
recommended for mosquito control may be effective
under some conditions, particularly if applications
are made when the adult flies are active. In
areas of heavy populations of Tabanus and
Chrysops, the use of adulticides has not proved to
be overly satisfactory. The use of larvicides has
the same drawbacks as described for the larval
control of biting midges. The personal protective
measures described for mosquitoes (see article
8-35) are fairly satisfactory for protection against
these flies, except that current standard repellents
are not always successful. Horse and deer flies
will occasionally enter quarters, but not for biting;
consequently, protection while in quarters is not a
problem.
9 Nov 2004
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