Both the Phorid Fly and the Fruit Fly are small flies. They come from two different fly families
and are often are mistaken for
each other. They are about 1/8 in long and somewhat similar looking, but
their biology and management are very different. The drain fly/moth fly
and the phorid flies are both common in drains, however occasionally the
fruit fly may come from a drain area.
Just because you may see a small fly or gnat type flying
around in the kitchen, do not assume it is coming from the drains. Check
all possible breeding sources to help identify the fly. Using a drain
cleaner like DF 5000 would only work in they are breeding in the drains.
Understanding the different breeding sources for the different
flies will help you in identifying and managing the respective flies.
The other flies that are found around drains are: Fruit Flies, Drain Flies
and Sphaerocierid Flies.
Breeding Sources of Drain Flies, Fruit Flies,
Phorid Flies and Sphaerocerid Flies:
Drain flies: breed
in drains, sewers, septic tanks and soil that has been contaminated with
sewage.
Fruit flies:
can be spotted around fresh fruits/vegtables, rotting fruits and vegetables,
drains, garbage and damp organic materials
Phorid
Flies : are found in sewage contaminated soil, garbage, drains,
human cadavers, rotting vegetables and fruit, garbage as well as damp
organic materials
Sphaerocerid
Flies: may be found in manure, damp organic material, drains,
rotting fruits and vegetables and garbage
Phorid Fly Identification
The phorids, also known as humpbacked flies, are small flies that resemble
fruit flies in appearance.
They are usually tan to dark brown in color. The Phorid fly lacks
the red eye color that is the classic trademark of the fruit
fly.
Phorid flies are in the small category of flies, measuring up to 1/8
inch in length, including the wings.
The most prominent feature of this fly is the humpbacked shape of its
thorax. The severe arch of the thorax gives it
the common nickname of humpbacked fly.
A key indentifying trait is that the adult Phorid fly has a distinctive
habit of running rapidly across surfaces instead of immediately flying
when disturbed. Most flies immediately take flight.
Phorid flies are also know as coffin flies, when found in mortuaries
and mausoleums.
Phorid flies have also been found to breed in poorly stored meats, damaged
containers of moist foods, and organic-based glues and paints.
Adults phorid flies are most active during the warmer months of the
year, but can be active during the winter months.
The Phorid fly is common in many habitats, but are more abundant in
decaying plant and animal matter.
The phorid fly breeds primarily in and feeds on moist decaying organic
matter.
The phorid fly can be found breeding wherever moisture exists, such
as around plumbing and drains in bathrooms and kitchen areas, garbage
containers, crawl spaces and basements.
Because it frequents unsanitary areas (with the ability to spread disease
causing bacteria onto food products) this fly is of particular concern
to hospitals, health care facilities and restaurants. Phorid fly larvae
have been found in the open wounds of patients in health care facilities.
The Phorid fly life cycle is : egg, larvae, pupa and adult. Eggs are
depostited on or near surfaces of decaying organic matter. The female
phorid fly will lay about 40 eggs over a 12 hour period. The larvae
emerge and feed for several days, then crawl to a drier spot to pupate.
The life cycle varies from 14 days to 37 days.
Inspection Tips for the Phorid Fly
Adult Phorid flies are fairly common in many habitats, but are most
abundant about decaying plant and animal matter. When searching for
Phorid fly breeding sources, remember that the larva can only survive
in decaying organic matter that is moist.
In structures, phorid flies can be found breeding wherever moisture
exists around plumbing and drains in bathroom and kitchen areas, garbage
containers, garbage disposals, crawl space areas and basements.
When searching for the breeding sources of phorid flies, keep in mind
that the larvae can survive only in moist, decaying organic matter.
The first spot that should be checked are the floor drains, if any are
present. Fly larvae live in the moist film that develops on the sides
of a drain and in debris which may become trapped on the edge of the
drain. The presence of numerous adult flies inside a drain is a good
sign that the drain is a breeding site. Use a knife or screwdriver to
scrape the film off the sides of the drain and examine it for live larvae.
Occasionally, drain pipes will break under slab floors, and phorid
flies can breed in immense numbers in the organic debris deposited through
the break in the pipe under the slab.
To determine if phorid flies are exiting through cracks in a floor
or from a drain, place pieces of masking tape over the crack or the
drain opening. Leave space between the strips of tape to allow air movement
for the flies to follow. If flies are exiting the openings, some of
the them will become stuck to the tape.
Other areas to check are where any fruits or vegetables or stored outside
of refrigerators or coolers.
Also inspect recyling bins, garbage cans, and underneath refrigerators.
In commercial and residential structures, tiny amounts of organic
debris are often found where the legs or feet of appliances, tables
or cabinets touch the floor. Restaurants, bakeries and food processing
facilities use water hoses to wash the floors. Water under pressure
can force food debris and moisture into the cracks and crevices where
it ferments and starts breeding sites.
These breeding sites can harbor thousands of fly larvae. All small
cracks and crevices at floor level need to be inspected and thoroughly
cleaned. Use a small spatula or knife to scrape any debris from inside
the cracks and crevices for inspection of live larvae.
Flies are not always breeding near where they are found. Because they
can fly, the breeding source can be located in another area.
Phorid flies easily follow air currents and usually have several breeding
places in any structure.
Do not assume that all of your breeding sources are indoors; phorid
flies will wander in from nearby dumpsters, outdoor garbage cans or
even damp compost piles where fruits and vegetables are disposed.
Trash containers which are not cleaned regularly are another good source
for phorid flies.
Other sites where phorid flies might be found include garbage disposals,
rotting meat and vegetables, the overwatered soil of potted plants,
and fresh flowers in vases. They have also been found breeding in dirty
mops in janitor closets and laundry rooms, animal feces, faulty septic
systems, and human cadavers. Don't stop looking when one breeding source
has been found. In most cases, several breeding sources will be present.
Phorid Fly Control Recommendations
It is necessary to inspect for breeding sites and remove them. Also
look for potential breeding sites and eliminate those.
As you can read from above their are many potential areas that serve
as a breeding site, so this is the most difficult area of control.
It is crucial to regularly clean floor drains. Bleach
and hot water will not eliminate fly larvae breeding in a drain.
A
use of a drain cleaner such as 
Invade Bio Gel Treatment
will remove the organic debris where the larvae live.
If the Phorid flies are breeding in the soil under a concrete slab,
the only way to eliminate the infestation is to remove the contaminated
soil by breaking through the slab and replacing the soil. Any broken
pipes need to repaired. Although this is costly, drilling and treating
the infested soil under the slab with residual insecticides does not
work.
Remove all organic debris trapped in small cracks and crevices under
the legs and bottom edges of kitchen equipment.
The debris needs to removed, thoroughly dried and a long lasting caulk
applied to seal the crack.
Invade Bio Foam
Another type of product, particulary useful in commercial establishments is a concentrated bio liquid with the use of a foamer like the Invade Bio Foam.
Invade Bio Foam contains concentrated scum eating, odor eliminating microbes and foaming agent. InVade Bio Foam - Super-concentrated
foaming microbial/citrus liquid to eat through scum where flies breed.
InVade Bio Foam - the single most effective tool for
management of small flies. Foaming microbial concentrate with proprietary citrus
oil. Use 1 oz per quart, 4 oz per gallon.
Apply using a 
Chapin foamer or sprayer to cracks, crevices and drains where small flies breed. The foam and citrus combination shuts down the breeding when applied, and over time the premium blend of microbes will digest the bio film to prevent further breeding in those areas.
InVade Bio Foam is a must for the PMP to manage fruit, drain and phorid flies in commercial accounts.
Ultra-concentrated InVade Bio Foam is mixed with water at a rate of 4 oz
per gallon (1 oz per quart) and applied using Foam Sprayers
Invade Hot Spot
Microbial/Citrus Foam in an
easy-to-use 16 oz aerosol can
The power of InVade Bio Foam is now available at your fingertips! Hot Spot is an aerosol can that contains the same premium microbes and ingredients as InVade Bio Foam. The 360 degree valve allows for foam dispensing in any orientation to easily hit hard-to-reach areas.
If adults do not disappear within a week further treatments
or looking for other breeding sources is needed .
After
breeding sources have been removed a space spray such a pyrethrins,
a non residual
insecticide can be applied to kill the adult flies.
Again it is important to remove breeding sites first as a control measure.
Another
tool you could use would be insect
light traps, but they attract mostly male phorid flies. There use
involved with this type of fly would be limited except as a tool for
monitoring.
