Free Shipping on Orders of $25 or More! (Shipping Only Available to the Continental U.S.)

Why Are Flies Hard to Swat and Spray?

It’s an all too familiar scene. You step up to the plate with the swatter in your hand. You put all your energy into the swing…and you miss. The fly buzzes by you without a care in the world.

When a pesky fly ends up in your home, your first thought is probably to use a fly swatter. Unfortunately, it always seems like the fly wins the game and you’re not sure why. We’ve gathered information about why flies are so hard to swat and spray to help you the next time you face off with one of them.

Fly 101


Before diving into how flies easily avoid us, it’s important to know a little bit about them. There are about 16,000 species of flies in North America. Flies are smaller insects with an oval body shape. They have two wings and typically land often.

Two flies that are notorious for ending up in your home are the house and cluster flies. House flies range in size from 4-7.5mm. These flies are gray with black stripes and their body is covered in short hair. Cluster flies grow between 8-10mm. Their abdomen has a gray, checkered pattern and they are covered in golden, short hair.

Flies have compound eyes with up to 6,000 lenses on each. This allows them to have a wide field of vision.

Slow Motion Vision

Fly's eyes

The eyes of a fly play a big role in their ability to avoid being swatted or sprayed. Their wide field of vision allows them to see an approaching threat from all sides. However, their brain plays an even larger role.

Though life is viewed as continuous motion, it’s actually multiple images being grouped together. The brain and eyes work together to convert light into these images. The rate that this happens determines how your vision works and different species have different processing speeds known as flicker fusion rate.

Flies have the upper hand in battles because they process image extremely quickly. Humans see 60 flashes of light per second while flies see around 250 flashes per second. This means that they see the world in slow motion. Though you think you’re being fast when you swat at them, you’re actually moving slow in their eyes.  

Flying Skills


Flies use their slow motion vision to avoid danger. They also rely on their flying skills.

Flies are known to execute some neat flying maneuvers when trying to avoid being squashed. When a fly senses an approaching threat, they freeze. They are able to quickly reposition themselves and then rapidly move their legs and wings to move out of the way. This is done so fast that if you blink, you would miss their movement.

They are capable of changing the direction they are flying in 1/100 of a second. Not only do they move quickly, they can also roll up to 90 degrees. Each movement they make is controlled and precise. The location of the threat determines which way they move.

What Can You Do?

Flying Insect Killer

No one wants flies to take over their home, but their defense mechanisms make it seem impossible to stop them. The good news is that there are ways to keep your home free of flies.

One of the best things you can do is make your home as uninviting as possible. Keep your doors and windows closed and repair any screens with tears. Keep food sealed and make sure to remove trash regularly.

If you’re feeling lucky and want to try to swat or spray them, it’s best to think ahead. Don’t aim directly at the fly. Swing or spray slightly in front of them to anticipate the fly’s movement.

Another option is to use a spray that not only kills on contact, but also has residual repellency like Maggie’s Farm Simply Effective Flying Insect Killer. Even if you aren’t able to spray the fly directly, the non-harmful residues will act as a repellent and keep them away.

Even if flies have caused you to strike out before, it doesn’t mean you can’t win the next game. When you try to swat or spray them, remember to anticipate their movement. Spraying or swatting a small distance from their starting point can help you make contact. If you’re dealing with a pest problem, we have your back! Check out our Maggie’s Farm Simply Effective Pest Control products.

Leave a comment

Please note, comments must be approved before they are published