Site Accessibility Information Access Key 1 to Skip to Top Navigation Access Key 2 to Skip to the Three One One link Access Key 3 to Skip to City of Winnipeg Main Menu Access Key 4 to Skip to Left Navigation Menu Access Key 5 to Skip to Content area Access Key 6 to Skip to Right Sidebar content area Access Key 7 to Skip to Footer Links
Insect Control

Biting Flies

What are biting flies?

Biting Fly

Biting Fly

Black flies, Biting midges (No-see-ums), Horse flies, Deer flies and Stable flies are all biting flies. Many of these species require a blood meal in order to lay eggs. In most species only the female takes blood meals. Some biting flies have piercing mouthparts to pierce the skin, inject an anticoagulant containing saliva and get a blood meal, while some have scissor-like mouthparts to cut into the skin causing a blood flow that they will feed on. Biting flies locate victims by sensing certain substances, including carbon dioxide and moisture in exhaled breath, dark colors, movement, warmth and perspiration.

What do black flies look like and where do they live?

Black Fly

Black Fly

Black flies are small, dark colored and about 2-4 mm in length with a humpbacked appearance. They develop in moisture environments and running water. Adults can fly considerable distances in search of blood. These flies are most common in spring and early summer.

What do biting midges look like and where do they live?

Biting Midge

Biting Midge

Biting midges are tiny bloodsucking flies that resemble tiny mosquitoes. Biting midges range in size form 1-3 mm in length. Their small size allows them to penetrate window and door screens. They are numerous along seashores or along the shores of rivers and lakes. Unlike black flies, the biting midges do not travel very far from the water.

What do horse flies look like and where do they live?

Horse Fly

Horse Fly

Horse flies are large flies that are usually solid black and range in size from 20-30 mm in length. They may be striped like a wasp and occasionally have metallic eyes. These flies are able to take large chunks of flesh from their victims. Horse flies have a flight range of several kilometers.

What do deer flies look like and where do they live?

Deer flies are similar to horse flies but smaller in size ranging from 12-25 mm in length. Deer flies are black with yellow-green markings on the thorax and abdomen. Their eyes are bright green or gold with patterns and their wings have a distinctive brownish-black pattern. The bite is much like that of the horse fly.

What do stable flies look like and where do they live?

Stable flies are very similar to houseflies in appearance but both sexes bite. Stable flies range in size from 4-7 mm. They develop in piles of decaying straw, manure, grass clippings or other piles of rotting vegetation. There are several generations per year; therefore the stable fly can be present in high numbers, especially in livestock.

How can I control biting flies using cultural/non-chemical control?

Flies are best controlled by eliminating favorable development sites, however since most flies develop in water this can be very difficult. Stable flies can be controlled by simply eliminating any decaying straw piles or by spreading out wet straw to dry. Avoid areas of high biting fly concentrations when the adults are active. Wear light coloured, loose fitting clothing - most biting flies are attracted to dark colours.

How can I control biting flies using chemical control?

Use approved repellents; those containing deet are most effective. As most flies develop in water, applying a chemical is not advisable unless spraying is done at the community level by a commercial applicator. Stable flies can be controlled by treating fly resting surfaces or host animals with a residual spray, which is usually required in livestock operations. All Pest Control products purchased and used must be registered with Health Canada and contain a Pest Control Product (P.C.P. or PCP) Number on their label.

How can I control biting flies using biological control?

There is a parasitic wasp currently being studied for control of the stable fly. Any biological insecticide available for black fly control would still have to be applied by a commercial applicator.

Last update: July 21, 2020
Contact Us
or 1-877-311-4WPG
Media inquiries: 204-986-6000

Administrative Office and Research Laboratory
1539 Waverley Street
Winnipeg MB R3T 4V7

Operations Base
3 Grey Street
Winnipeg MB R2L 1V2
Citizens' Information Service
Search by address
to find out your insect management area.

Was this information helpful?

How can we make this web page better?

Information collected will be used to improve our website. Do not use this form to submit a request for service or information because it will not be forwarded to departments for response. To submit a request for service or information, contact 311.

This form is not intended to collect personal information; however, any personal information you choose to include in your comments is collected by the City of Winnipeg under the authority of section 36(1)(b) of the Freedom of Information and Protection of Privacy Act for the purpose of improving our website and will not be used or disclosed for any other purposes, except as authorized by law. Contact the Corporate Access and Privacy Officer by mail (City Clerk’s Department, Susan A. Thompson Building, 510 Main Street, Winnipeg MB, R3B 1B9) or by telephone (311) if you have any questions about the collection of this information.

Ces renseignements sont-ils utiles?

Comment pourrait-on améliorer cette page Web?

Les renseignements recueillis serviront à l’amélioration de notre site Web. Prière de ne pas se servir de ce formulaire pour soumettre une demande de service ou de renseignements, car la demande ne sera pas transmise au service en question. Pour soumettre une demande de service ou de renseignements, veuillez communiquer avec le 311.

Le présent formulaire ne vise pas à recueillir des renseignements personnels. Cependant, les renseignements personnels que vous choisissez d’inclure dans vos commentaires sont recueillis par la Ville de Winnipeg en conformité avec l’alinéa 36(1)b) de la Loi sur l’accès à l’information et la protection de la vie privée dans le but d’améliorer son site Web et ne seront ni utilisés ni divulgués pour d’autres raisons, sauf dans les cas où cela est autorisé par la loi. Communiquez avec l’agent de l’accès à l’information et de la protection de la vie privée de la Ville par courrier au Bureau du greffier, immeuble Susan-A.-Thompson, 510, rue Main, Winnipeg (Manitoba) R3B 1B9, ou par téléphone au 311 si vous avez des questions sur la collecte de ces renseignements.