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How Does Fly Spray Work?

Rowan Burgess |

As a poultry farm manager, you understand the importance of keeping your facilities free of flies. Not only do they pose a nuisance to your birds, but they can also spread diseases and contaminate feed. 

Fly spray must become an essential tool in your insect control arsenal. But have you ever stopped to think about the science behind this effective solution? 

In this guide, we'll take a closer look at how fly spray works, examining its various active ingredients and mechanisms of action used to eliminate flies in your poultry farm - effectively. 

The Chemistry Behind Fly Spray

Simply put, fly spray kills nuisance flies. This spray contains chemicals acting as a neurotoxin, which block an enzyme called acetylcholinesterase in the fly's body. This enzyme stops the flow of information between the fly's nerves and muscles. Without it, the fly's muscles contract, and it becomes unable to move its abdomen. As a result, the fly eventually suffocates and dies.

In short, fly spray works by blocking an essential enzyme in the fly's body, causing its muscles to contract and making it unable to breathe, leading to its demise.

How Long Does It Take for Fly Spray To Kill a Fly?

When fly spray is applied correctly, it may only take a few seconds. However, larger or stronger flies may take longer, up to a few extra seconds. After the initial 10 seconds, the fly may still move due to muscle spasms. 

However, a fly spray’s timeline depends on the type of solution used, the concentration of the active ingredient, and the size and species of the fly. 

How Does Fly Spray Work So Fast?

Fly spray works quickly because it contains chemicals that are toxic to flies. The active ingredient in the fly spray acts as a neurotoxin, which interferes with the fly's nervous system. 

This fast-acting mechanism makes fly spray an effective tool for quickly and efficiently killing flies.

What Does Fly Spray Do to Humans?

Fly spray may affect humans depending on the specific chemicals used. Some common active ingredients contained can be toxic to humans if ingested or inhaled.

Also, some fly sprays contain pyrethroids, which may cause skin irritation, itching, and redness. In rare cases, they can also cause more severe symptoms such as difficulty breathing, coughing, and vomiting.

It's critical to follow label instructions and use protective measures such as wearing gloves or a mask and avoiding inhaling the spray. If you experience any symptoms after using the product, seek medical attention immediately. It's also crucial to keep fly spray out of reach of children and pets.

Which Fly Sprays Do We Recommend?

Finding the right fly spray for your poultry farm can be challenging, but we’re here to help. 


VULCAN P RFU Fly Spray is a highly effective and safe insecticide spray used for fly control. This product contains pyrethroids and piperonyl butoxide, providing quick knockdown and long-lasting residual control. It's suitable for use in industrial poultry farms and other livestock premises. 


The INSECTO FLY & WASP DESTROYER is a powerful insecticide aerosol spray that provides quick and effective control of flying and crawling insects. 

Its active ingredient, Deltamethrin, is a pyrethroid insecticide that targets the nervous system of insects, causing immediate knockdown and death. This product is safe to use around food, pets, and children, and its 300ml aerosol can provide long-lasting protection.


Insecto Smoke Bomb effectively controls flies and insects in enclosed spaces. Its compact size makes for convenient carrying, and it releases a dense smoke filled with a pyrethroid insecticide. This smoke quickly spreads, killing insects in its path without leaving any residue. 


DIGRAIN INSECT KILLER SPRAY contains natural ingredients, including pyrethrin and piperonyl butoxide, making it a safe and effective option for indoor and outdoor use. Its fast-acting formula provides quick results, making it an excellent choice for insect control.

Frequently Asked Questions

How Long Does Fly Spray Last in the Air?

The effectiveness of fly spray in the air depends on the spray used, the size of the treated space, and the surrounding environmental conditions, such as ambient temperature and humidity. Generally speaking, fly sprays last between 10 minutes and 2 hours in the air.

Does Bug Spray Work on Flies?

Yes, bug spray is effective against flies. It contains neurotoxic chemicals that disrupt flies' nervous systems, causing quick paralysis and death. The active ingredients, like pyrethroids, target flies' muscles and respiratory functions. However, efficacy varies based on spray type, space size, and environmental factors.

Final Thoughts

Fly spray is a powerful tool in the fight against flies and the health hazards they pose in poultry farms. By understanding the active ingredients and mechanisms used in these insect control solutions, you can make informed decisions when choosing the right products for your farm.

At Dalton Engineering, we're the leading supplier of fly control products, offering a range of solutions to keep your poultry farm fly-free. 

From sprays to smoke bombs, we have the products and expertise to help you manage your fly control program effectively. Get in touch today to learn more about how we can help keep your poultry farm healthy and in good working order.