Does UV Light Kill Fleas? [UV light vs Fleas]

Direct exposure of fleas to UV light in the C spectrum (UVC) is toxic to them. It will penetrate and damage their cells. Fleas move so fast therefore you need visual help like ultraviolet light to find and kill them in the dark.

To kill fleas with UV light, expose them to 280nm UVC rays for 30minutes at a distance of 10cm. The larvae will die when exposed to UV rays for 15minutes. Mature fleas will perish in 25-40minutes depending on the size.

Fleas produce a visible reflection when UV light strikes them. This is why you can use ultraviolet light to find and eliminate them in darkness. It is the best way to verify the type of pest you are dealing with.

Does UV Light Kill Fleas?
UV light vs Fleas

Are fleas attracted to UV light?

Fleas are attracted to UV light because they do not have eyes that can visualize images. They need a minimum of 300nm UV wavelengths to help them in detecting their host movements. Fleas detect green, blue, and yellow UV rays faster when compared to other colors.

UV rays attract fleas because they use the same when moving. They all have a tendency of moving towards warm sharp rays. Since they survive in the dark, their ability to detect UV rays helps them to identify their prey.

However, fleas hide from normal light with no UV rays. This is why it is not easy to see them. UV light is unique and different from normal light. It has a high weave length and that gives it stronger energy as compared to the rest.

Do fleas glow under UV light?: Fleas glow under UV light because their outer layers absorb UV rays thus making them visible in the dark. When fleas are in a dull room with poor lighting, finding them can be difficult because they hate natural light.  

Fleas also have phosphors on their outer shell. This makes them glow in the dark when UV light strikes them. This is why it is used to find them in places with poor visibility. Fleas on wooden floors cannot be easily seen and this is where UV detection can help.

Does UV light kill flea eggs?

Irradiation of fleas eggs in UV-C light that is 100-280nm for 15-30 minutes will kill them. This will penetrate and destroy the DNA structure of the fleas’ eggs thus stopping them from further development. To be effective, eggs need to be placed at least 20 cm from the UVC light source.

This will also destroy all the stages of a flea’s life cycle if they are exposed close enough to it. The UV light rays destroy and stop the egg development by inducing lesions to their DNA. UVC is used to control fleas and other insects in areas where they are not required in a lab.

The cells in a flea egg will get super active when possessed to UV light. The longer the exposure, the higher the activity and this will weaken them. When they become weak, they can no-longer sustain the development phase and this will kill the egg development.

The rays emitted from UVC light are therefore toxic to fleas’ eggs because it penetrates into every single cell. Those cells are very weak and cannot sustain the energy that is released from the UV rays. Fleas eggs are immobile and UV rays will be effective in killing them because there will be maximum cell penetration.

How to trap and kill fleas using UV light rays

Ultraviolet rays can be used to make a flea trap because fleas will jump towards the rays. To make a UV fleas trap, place a UVC light above a basin of soapy water near the infested area. The rays will draw them from their hiding areas and they will drown in the soapy water below.

Yellow or green UV lights are the best to use against fleas since they can easily sense and hop towards them. However, red UV will not attract fleas because just like other insects, they will struggle to detect and find it.

UV fleas traps can be placed in areas where pets sleep. Do not use the UV rays on your pet’s skin because they may react to it in some cases. If possible, use the trap when the pets are away because fleas will choose the host over light.

You can also place infested bedding under sharp UV rays and this will kill them plus their young ones. However, it is advisable to do this after cleaning the bedding. High temperatures are deadly to fleas and the high energies released by the UV light is what will kill them.

Pros and cons of UV light against fleas

For UVC irradiation to be effective against fleas, it has to be very close. The exposure duration should also be high. You need to have the fleas at a constant place and if possible trapped in an area. Fleas will start hoping and jumping away under the light when it starts to burn into them.

If you place a single UV light in a room, it will really take long for it to kill fleas. Fleas will look for hiding areas when the light starts affecting them. This means that using UV light against fleas in a wide room will not be effective.

Fleas will only come out when they are hungry and desperate.  If they have a constant host and they are full, they will not come out because of the light. Fleas need a host to survive and lay eggs and the UV light only attracts them when they are hungry.

Ultraviolet rays will also be less effective in a bright room. It will only work in a dark room with the help of a trap like a basin of soapy water. Naturally, fleas will always avoid natural light because it is bright enough to expose them. You cannot use this method to remove fleas in carpet or furniture because it is an open space.

Ultraviolet rays are also dangerous to humans. They should never be used to get rid of fleas in bed at night while you sleep. Long exposure can be toxic to the skin. However, UV light can detect bed bugs and this can be used to find and kill them in a dark room.

Irradiation from normal light will never work against fleas. The UV rays used must also be in the C spectrum to achieve the desired results. In case you find them, do not squish fleas with your hands to kill them.


  • Felix Odi

    Hi, I’m an experienced author and content creator with over 18 years of experience as a publisher. Growing up in rural areas of Bristol, FL, I developed an interest in pest control, fish farming, and poultry keeping. Farming is a main activity in the area, and pests are always part of our major setbacks. I had to learn how to get rid of them with simple DIYs.