The eggs of fleas (and other insects) don’t easily die in water. However, washing machines do kill flea eggs. They can’t survive the detergent, water, heat, and physical tumbling action. It’s recommended to wash items at 140°F for ten minutes, and then dry at the highest heat setting.
Insect Eggs & Water
Insect Eggs are Difficult to Drown
Most insect eggs don’t drown easily when submerged in water. There aren’t any specific studies done on fleas, but eggs of the rove beetle can survive for 3-4 days when immersed in water.
Plastrons Extract Oxygen from Water
Eggs of many insect species can extract oxygen from water with a special structure called a plastron. Thus, they can survive and develop even when their environment is flooded. A plastron is a gas layer within the chorion (shell). It’s held together by a mesh which prevents water from entering the egg. In the past, it was believed that only eggs of aquatic insects had a plastron, but it’s now known that eggs of many terrestrial species also have this feature.
The Structure of Cat Flea Eggs
Cat flea eggs are more fragile than other insect eggs. The chorion is gelatinous and single-layered, only 1 pm in thickness. It provides physical protection to the embryo and allows for respiration. Gas exchange occurs through pores called aeroplyes which connect to an air-filled chamber within the chorion. The exact function of this gas layer is unknown, because flea eggs don’t usually contact water. It may function as a plastron, draw in moisture from the environment, or store air in case of water immersion.
How to Kill Flea Eggs in Water
When insect eggs are treated with alcohol, the plastron gets compromised and can’t function. The treated eggs will die in water within minutes.
Adding dish soap to water also kills insect eggs. Soap is believed to have a similar mode of action as oil. It penetrates the eggs and then either interferes with metabolism or suffocates the embryo.
Do Washing Machines Kill Flea Eggs?
Washing machines will kill flea eggs, as well as other life stages. It’s advised to wash items, such as pet bedding and rugs, at 140°F for ten minutes. Then dry the items using the dryer’s maximum heat setting.
Flea eggs are non-adherent, so they won’t stick to laundered items. Most of the eggs will fall off of the fabric and into the water, ultimately ending up in the sewer. Regardless, the eggs will likely die from the detergent, heat, and physical trauma. If the eggs happen to survive and remain on the items, the dryer will desiccate and kill them.