Black Flies

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Elizabeth Sowards 4th period January, 99 Black
Fly Project
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Black Flies

• A member of the family Similiidae (Diptera).
• There are more than 1,000 known species.
• They are also known as the Buffalo Gnat.

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Identification

• The black fly is 1-5mm in length.
• They are misnamed because most of them are gray
  and others are light tan to yellow in color.
• Adults are typically robust with a characteristic
  arched or humped prothorax.

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Feeding

• Both sexes feed on the nectar of flowers.
• Only the females require a blood meal for ovarian
  development.

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More fun facts

• Although a given species may prefer a particular
  animal host, most will readily feed upon other
  host species as well.
• Black flies attack man and a wide variety of
  domestic and wild animals and birds others feed
  only on cold-blooded animals.
• Many important pest species belong to the genus
  Simulium.

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Reproduction

• Females deposit 150-500 creamy-white eggs that
  darken until they are almost black just prior to
  hatching.
• The eggs are usually are deposited in masses on
  some convenient object in or near the edge of
  flowing water.
• The water can be slow-moving, but most species
  prefer rapidly flowing water.

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Reproduction

• Breeding may occur in marshy areas
• The time required for hatching varies with the
  species and may be 3-5 days or as long as 30 days
  at low temperatures.
• Larvae most often are found just beneath the
  surface of rapidly flowing water.

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Reproduction

• Duration of larval development, like the egg
  stage, varies with species and temperature it
  may range from 10-14 days to 7-10 weeks.

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More fun facts

• Some species overwinter as larvae.
• Winter is usually passed in the egg stage.
• The last larvae instar spins a reddish-brown,
  basket-like cocoon in which pupation occurs.
• These cocoons are attached to slightly submerged
  objects such as rocks, logs, roots, and other
  debris.

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More Fun Facts

• Pupae also possess respiratory filameters with
  which they remove dissolved oxygen from the
  water.
• The pupal period varies from 4-5 days to as long
  as 3-5 weeks, depending on water temperature and
  species.
• Mating usually occurs shortly after the initial
  flight.

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Life Cycle Habits

• 1. Simulium vittatum Zetterstedt - This species
  is strictly a nuisance attacking horses and
  cattle, but not humans. It does fly around
  peoples faces. Breeding occurs in rich
  productive streams such as polluted (sewage)
  areas, at beaver dams, etc. It is dark gray to
  velvety black. (Widely Distributed in North
  America.)

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Life Cycle Habits

• 2.Simlium venustum Say - This species is a
  nasty biter feared by fishermen and campers. The
  season extends from May to September with
  greatest numbers in June and July. They are
  usually troublesome in late summer. It is
  recognized by its white-marked tibiae (leg
  parts).(Widely distributed, especially in New
  England Canada.)

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Life Cycle Habits

• 3.Simulium jenningsi - This species breeds in
  huge rivers (one mile or so wide). In
  Pennsylvania, New England and other states, there
  is currently a multimillion dollar program
  applying a biological larvicide known as Bacillus
  thuringiensis Berliner subspecies israelensis
  (B.t.I.) into streams and rivers to control
  larvae before adult emergence.

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Life Cycle Habits

• 4.Prosimulium sp.. - This species occurs in early
  spring (April to May). It is a nuisance by both
  swarming and biting. Larvae occur in small
  woodland streams. It is the first black fly
  species to appear each year.

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Control Measures, Prevention Insecticides

• There is little that a homeowner can do to
  control black flies.
• Bites can be treated with soothing lotions as
  well as corticosteroids to relieve pain and
  itching and help leisons resolve.
• If the reaction is mild, oral antihistamine
  therapy may suffice, but severe reactions
  involving shock may require epinephrine (consult
  your physician).

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Control Measures, Prevention Insecticides

• Prevention
• Some avoid outdoor activities during the black
  fly season.
• One can purchase hats with fine mesh netting
  extending over the face and shoulders from
  camping supply and mail order houses.

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Control Measures, Prevention Insecticides

• Repellents offer some relief depending on the
  individual, species of fly, temperature,
  humidity, time of day, etc.
• There are times that flies will bite regardless
  of the repellent and concentration used.
• Protection sometimes lasts for two to two and
  half hours.

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Control Measures, Prevention Prevention

• Any of the following repellents can be used such
  as deet (Cutters, Diethyl-toluamide, Off),
  citronella oil (Skin So Soft), ethyl hexanediol
  or dimethyl phthalate.

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Control Measures, Prevention Insecticides

• As a whole, the individual can merely resort to
  household sprays, aerosols, repellents and
  screens (60 mesh bolting cloth) to cope with this
  pest.
• Some persons indicate that unpainted aluminum
  hard hats attract black flies.

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Control Measures, Prevention Insecticides

• A thin film of fuel oil smeared over the outer
  surface traps flies in the oil, giving the wearer
  much protection.
• The best methods of control are directed toward
  reducing the number of black fly breeding areas.

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Control Measures, Prevention Insecticides

• Insecticides
• Fogging for black flies provides temporary relief
  since only those flies that contact the fog are
  killed.
• Later migrants into the treated area are
  unaffected.
• Daily treatments of pyrethrins usually is
  necessary.

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Control Measures, Prevention Insecticides

• Treatment of breeding areas in rivers, streams,
  etc. is effective when the application timing is
  correct.
• Large scale efforts are needed such as by a
  government agency skilled in coping with black
  flies.
• It is necessary to treat large areas where larvae
  occur by helicopter or airplane.

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Control Measures, Prevention Insecticides

• Also, crews spraying streams and other bodies of
  water, and fog machines and mist blowers to kill
  adults, is helpful.
• There are many insecticides such as a bacterium
  called Bacillus thuringiensis Berliner var.
  israelensis, this is nontoxic to nontarget
  beneficial organisms such as fish, birds, etc.
  Other insecticides are permethrin, chlorpyrifos ,
  and hypermethrin.

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Bibliography Lyon, William F. Entomology Black
Flies. http//www.ag.ohio-state.edu/ohioline/ h
yg-fact/2000/2167.html Aug. 28, 1998 Robinson,
James V. Extension Entomologist.
http//entowww.tamu.edu/extension/ bulletins/uc/
uc-019.html. Aug. 28, 1998