Phorid
flies, also known as humpbacked flies,
are tiny flies associated with filth and
often confused with fruit flies. They
breed in decaying organic matter and
thus become problematic in hospitals,
food establishments and homes as well as
outdoors.
Phorid flies measure 1/16th to 1/8th of
an inch long and have a humpbacked
appearance. They look similar to fruit
flies because of their small size, but
lack the characteristic red eyes that
fruit flies possess. The larvae of
phorid flies are elongated, cylindrical,
slightly flattened, and dirty white in
appearance.
Moist areas where food and water are
present are most conducive to phorid fly
breeding. Examples of these types of
places include burn units, operating
rooms, autopsy rooms, and morgues in
hospitals; faulty septic systems,
clogged basement drains, soil of potted
plants, garbage cans, rotting meat and
vegetables in homes; and kitchens, soft
drink machines, and garbage receptacles
in eating establishments. Phorid flies
lay their eggs on decaying organic
matter in such places as open wounds of
people and animals, decaying animal and
human flesh, feces, decaying insects,
laboratory culture media, clogged
drains, garbage cans, potted plant soil,
and garbage disposals.
To reproduce, flies lay about 20 eggs at
a time. Within 24 hours, the eggs hatch
and the larval (maggot) stage begins and
lasts for 8 to 16 days. After the larval
stage, the pupal stage lasts for 14
days, meaning life cycles take an
average of 25 days to complete.
Although they do not bite people, phorid
flies cause anxiety and worry because of
their presence in large numbers. When
they are visible in restaurants,
hospitals, morgues, autopsy rooms, and
other places, this can be a bad thing
for employees and visitors. Also,
because they frequent places associated
with filth, phorid flies can transmit
disease.
To treat for phorid flies, removing the
breeding sources for larvae is key. In
the meantime, pyrethrin or resmethrin
containing aerosols sprays can be used
to knockdown their population.
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