Elizabeth Sowards 4th period January, 99 Black Fly Project

Elizabeth Sowards

4th period

January, 99

Black Fly Project

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”.

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.

Feeding• Both sexes feed

on the nectar of flowers.

• Only the females require a blood meal for ovarian development.

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.

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.

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.

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.

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.

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.

Life Cycle & Habits1. Simulium vittatum Zetterstedt - This species

is strictly a nuisance attacking horses and cattle, but not humans. It does fly around people’s 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.)

Life Cycle & Habits2.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.)

Life Cycle & Habits3.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.

Life Cycle & Habits4.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.

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).


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.


• 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.

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.


• 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.


• 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.


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.


• 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.


• 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.

BibliographyLyon, William F. Entomology: Black Flies.

http://www.ag.ohio-state.edu/~ohioline/hyg-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

Documents

Elizabeth Sowards 4th period January, 99 Black Fly Project