Blow flies lay their eggs on animal remains and can spread disease. To control blow flies, it is important to remove dead animals and dispose of them properly, and to use effective insecticides when necessary

Tomberlin, Jeffery K.

Texas A&M University

ER-026 
6-06
Jeffery K. Tomberlin, Extension Entomology Specialist
The Texas A&M University System
Blow flies (Fig. 1) are non-biting flies found 
throughout the world. They feed and lay 
their eggs mostly on decomposing animal 
remains. Because of this, they often come 
in contact with human and animal patho-
gens. It is important to suppress blow fly 
populations to reduce the risk of spreading 
disease. 
Description
Blow flies are metallic flies about 1⁄4  inch long and can be found in urban 
or rural settings. Based on their appearance, they can be separated into 
two groups – green bottle flies and blue bottle flies. Green bottle flies are 
metallic green, but sometimes have a bronze tint. They are active during 
warm months of the year. Blue bottle flies are metallic blue to black or 
purple and are active during cooler months of the year. 
Life Cycle
The blow fly life cycle has four stages of 
development. A single blow fly can lay up 
to 2,000 eggs during its life. Eggs are de-
posited on decomposing animal remains 
and usually hatch in about 12 hours. The 
resulting larvae (Fig. 2) feed on the decom-
posing remains. When the temperature is 
about 80 degrees F, larval development takes 11 to 20 days. Larvae pass 
through three larval instars during that time. During the last stage, larvae 
leave the food source and form pupae (cocoons). Blow fly pupae are foot-
ball-shaped. Pupation lasts 6 to 12 days. 
Control
Blow flies can be suppressed with cultural and chemical control methods. 
Using both methods is most effective and least expensive.
Cultural control means changing the environment so that blow flies are 
no longer able to develop. The best cultural control method is properly dis-
posing any decomposing animal remains where blow flies might lay eggs. 
Controlling Blow Flies 
Figure 1. Adult blow fly.
Figure 2. Blow fly larva.
Dead animals (e.g., birds, cats, dogs and opos-
sums) should be buried at least 12 inches deep. 
You can also place them in garbage bags that you 
have tied tightly. Removing all food residues and 
cleaning garbage cans weekly will also make the 
cans less attractive to blow flies. Keep windows 
screened and doors closed to prevent flies from 
entering your home. Stores and other businesses 
can place exhaust systems above their doors to 
reduce fly access. They can also install doors that 
open and close mechanically. Sticky traps and 
ultra-violet light traps placed around homes and 
businesses will reduce blow fly populations.
Chemical control is effective with insecticides 
that contain pyrethrins. You can purchase insec-
ticide sprays labeled for home use at grocery and 
hardware stores. Fly baits, such as QuickBayt® 
and Golden Malrin®, are not recommended for 
controlling blow flies. These baits usually are sug-
ar-based and contain a compound that attracts 
only adult house flies. Always read and follow 
the directions listed on the insecticide label.
The information given herein is for educational purposes only. Reference to commercial products or trade names is made
with the understanding that no discrimination is intended and no endorsement by the Texas AgriLife Extension Service is implied.
Produced by AgriLife Communications and Marketing, The Texas A&M System
Extension publications can be found on the Web at: http://AgriLifebookstore.org
Visit the Texas AgriLife Extension Service at http://AgriLifeextension.tamu.edu
Educational programs of the Texas AgriLife Extension Service are open to all people without regard to race, color, sex, disability, religion, age, or national origin.
Issued in furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of Congress of May 8, 1914, as amended, and June 30, 1914, in 
cooperation with the United States Department of Agriculture. Edward G. Smith, Director, Texas AgriLife Extension Service, The Texas A&M System.


English

Controlling Blow Flies

Texas A&amp;M Repository

ER-026 6-06Jeffery K. Tomberlin, Extension Entomology SpecialistThe Texas A&M University SystemBlow flies (Fig. 1) are non-biting flies found throughout the world. They feed and lay their eggs mostly on decomposing animal remains. Because of this, they often come in contact with human and animal patho-gens. It is important to suppress blow fly populations to reduce the risk of spreading disease. DescriptionBlow flies are metallic flies about 1⁄4  inch long and can be found in urban or rural settings. Based on their appearance, they can be separated into two groups – green bottle flies and blue bottle flies. Green bottle flies are metallic green, but sometimes have a bronze tint. They are active during warm months of the year. Blue bottle flies are metallic blue to black or purple and are active during cooler months of the year. Life CycleThe blow fly life cycle has four stages of development. A single blow fly can lay up to 2,000 eggs during its life. Eggs are de-posited on decomposing animal remains and usually hatch in about 12 hours. The resulting larvae (Fig. 2) feed on the decom-posing remains. When the temperature is about 80 degrees F, larval development takes 11 to 20 days. Larvae pass through three larval instars during that time. During the last stage, larvae leave the food source and form pupae (cocoons). Blow fly pupae are foot-ball-shaped. Pupation lasts 6 to 12 days. ControlBlow flies can be suppressed with cultural and chemical control methods. Using both methods is most effective and least expensive.Cultural control means changing the environment so that blow flies are no longer able to develop. The best cultural control method is properly dis-posing any decomposing animal remains where blow flies might lay eggs. Controlling Blow Flies Figure 1. Adult blow fly.Figure 2. Blow fly larva.Dead animals (e.g., birds, cats, dogs and opos-sums) should be buried at least 12 inches deep. You can also place them in garbage bags that you have tied tightly. Removing all food residues and cleaning garbage cans weekly will also make the cans less attractive to blow flies. Keep windows screened and doors closed to prevent flies from entering your home. Stores and other businesses can place exhaust systems above their doors to reduce fly access. They can also install doors that open and close mechanically. Sticky traps and ultra-violet light traps placed around homes and businesses will reduce blow fly populations.Chemical control is effective with insecticides that contain pyrethrins. You can purchase insec-ticide sprays labeled for home use at grocery and hardware stores. Fly baits, such as QuickBayt® and Golden Malrin®, are not recommended for controlling blow flies. These baits usually are sug-ar-based and contain a compound that attracts only adult house flies. Always read and follow the directions listed on the insecticide label.The information given herein is for educational purposes only. Reference to commercial products or trade names is madewith the understanding that no discrimination is intended and no endorsement by the Texas AgriLife Extension Service is implied.Produced by AgriLife Communications and Marketing, The Texas A&M SystemExtension publications can be found on the Web at: http://AgriLifebookstore.orgVisit the Texas AgriLife Extension Service at http://AgriLifeextension.tamu.eduEducational programs of the Texas AgriLife Extension Service are open to all people without regard to race, color, sex, disability, religion, age, or national origin.Issued in furtherance of Cooperative Extension Work in Agriculture and Home Economics, Acts of Congress of May 8, 1914, as amended, and June 30, 1914, in cooperation with the United States Department of Agriculture. Edward G. Smith, Director, Texas AgriLife Extension Service, The Texas A&M System.

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Controlling Blow Flies

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Controlling Blow Flies

Abstract

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Texas A&M University

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