What would attract horseflies also known as deerflys to a residential neighborhood and how can you deter them?
Horse flies are attracted to damp, humid areas (swamp land) or
near rivers or streams. Insecticides don't seem to bother them, but
I did some research and came up with a trap for them. Although it's
not cheap $250 it apparently works well. Please go onto:
www.bitingflies.com/ Good luck Marcy I know that they like to fly
over water and bite when swimming. _______________
http://www.uri.edu/ce/factsheets/prints/deerhorseflies.html
University of Rhode Island GreenShare Factsheets
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Deer & Horse Flies Diptera: Tabanidae Horse flies and deer
flies belong to the fly family Tabanidae. Horse flies (genus
Tabanus) are considerably larger than deer flies (genus Chrysops).
Both horse flies and deer flies have large heads and large eyes.
Horse flies can range from 20 mm (3/4 inch) to more than 25 mm (1
inch) in length. A common species typically found near beaches and
saltmarshes is Tabanus nigrovittatus, or "greenhead fly." This
species has brilliant green eyes which are sometimes crossed with
red or purplish bands. Larger species of horse flies are brown to
black and have varying stripes or triangles on their abdomens. The
larger species of horse flies are less common, but inflict a
painful bite similar to other species of horse flies. The antennae
of horse flies are thick and lengthen into 5 thinner segments; the
antennae of deer flies are long and thin. The wings of horse flies
are usually clear or completely dark, whereas deer fly wings have
varying patterns. Deer flies are comparable in size to house flies
and are mostly yellow or black with varying stripes and shapes on
their abdomens. The wings of deer flies are usually marked with
dark patterns. Deer flies also have brilliantly-colored eyes,
ranging from gold to green, with large brightly-colored stripes.
Damage: Only female horse flies and deer flies feed on blood. Both
flies are vicious, painful biters which feed on the blood of
cattle, horses, mules, hogs, dogs, deer and other mammals,
including humans. These flies cut through the skin using
razor-sharp mouthparts that are shaped like a knife or razor. The
flies will then suck the blood up from the wound for several
minutes. This process makes these flies potential mechanical
vectors of such diseases as anthrax, tularemia, anaplasmosis, hog
cholera, equine infectious anemia and filariasis. Deer flies and
horse flies are also suspected of transmitting Lyme disease (New
England Journal of Medicine 322:1752, 1990). The open wound left by
the fly bite also permits secondary feeding sites for other
nuisance insects. Biting deer flies frequently attack humans along
beaches, streams, ponds, lakes and around woods and dirt roads near
large bodies of water. Some people suffer severe lesions, high
fever and even general disability when bitten. Allergic reactions
may occur from the saliva, which is poured into the wound to
prevent clotting while the fly is feeding. A person can become
increasingly sensitive to repeated bites. However, horse flies and
deer flies are generally thought of as primarily nuisance pests.
Life Cycle: The lifecycles of both horse and deer flies are
similar. The first stage of development is the egg stage. The eggs
are dark, shiny and spindle shaped. They are layered in masses
("tiers") which contain a few to several hundred eggs. These masses
are laid on vegetation which hangs over water. Eggs hatch within
five to twelve days, and small larvae drop down and burrow into
moist soil. Suitable habitats include saltmarshes, swamps, bogs and
areas along the edges of ponds, lakes and streams. Deer fly larvae
feed on organic debris and other small organisms. Horse fly larva
will feed on organic debris, insects, small crustaceans, snails,
earthworms and other organisms. Horse fly larvae are also
cannibalistic and will eat other larvae. Larvae overwinter in muddy
soils, maturing in late spring. In some cases, larvae take one to
three years to complete development. In late spring, the larvae
migrate towards dryer soils and develop into pupae. The pupal
period varies between species and may range from six to twelve
days, depending on temperature. Adult flies emerge from pupae and
immediately begin mating and blood feeding. Adults are strong
fliers, searching visually for hosts and mates. The females require
a blood meal for their eggs, but also feed on nectar and plant
juices for flight energy. Males also require nectar and plant
juices for flight. Control: Unfortunately, there are no
satisfactory methods for control of horse flies and deer flies. It
is impractical in most regions to eliminate their breeding areas,
especially along endangered wetlands, where these flies are
commonly found. Larval control is equally impractical, especially
in recreation areas or reservoirs. Adulticiding is not practical
because it requires the use of broad-spectrum insecticides, which
can be toxic to fish, birds and mammals. Traditional repellants are
not effective in keeping away horse and deer flies. Repellants
containing DEET (N-diethyl-meta-toluamide) do not prevent flies
from landing, although they may inhibit the flies from biting. The
greatest horse and deer fly activity occurs on warm, sunny days
when there is little or no wind. A slight drop in temperature or a
sudden breeze reduces biting attacks. Horse and deer flies are
visual insects, locating hosts by movement. Dark, moving objects
and shapes are most attractive to the flies. They are also
attracted to carbon dioxide that is released from their hosts. To
reduce exposure to bites, it is best to wear light-colored
clothing, including a light baseball cap, especially on warm, sunny
days when flies are most active. Many devices have been designed to
catch flies attracted to moving objects. One device is the trolling
deer fly trap. This device consists of a blue cup coated with
sticky material; the cup is placed outside of a moving vehicle,
attracting horse and deer flies with its movement and color.
Another device is the Tred-not Deer Fly Patch, which is a new,
non-chemical sticky patch for controlling horse and deer flies.
Some testers have reported good results from these odorless,
non-chemical, adhesive patches. The patches are 7.5 cm (3 inches)
wide by 15 cm (6 inches) long, and are worn on the back of a
baseball cap to trap and hold biting deer flies. A number of fly
traps have been developed which attract these flies using dark,
moving objects, as well as carbon dioxide and other attractants.
Although these traps will not completely eliminate all the flies,
they will reduce the populations to a more tolerable level.
Examples of trap designs include canopy traps, box traps, malaise
traps and light traps. Commercially available horse and deer fly
repellants are available for use on animals only. Most of these
repellants contain permethrin, which may be harmful to humans. One
must take precautions to use these repellants only as instructed.
Repellants safe for horses are not necessarily safe for other
animals. Always follow label directions. By Kristen Bartlett, 1999
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Pesticides are poisonous! Read and follow all safety precautions on
labels. Handle carefully and store in original containers out of
reach of children, pets or livestock. Dispose of empty containers
immediately, in a safe manner and place. Pesticides should never be
stored with foods or in areas where people eat. When trade names
are used for identification, no product endorsement is implied, nor
is discrimination intended against similar materials. Be sure that
the pesticide you intend to use is registered for the state of use.
The user of this information assumes all risk for personal injury
or property damage.
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For more information, call the URI CE Gardening and Food Safety
Hotline at 1-800-448-1011 or (401)874-2929 from outside Rhode
Island; Monday-Thursday between 9 am and 2 pm.
