How to Kill Flea Larvae

Tiny bloodsuckers that pack a big wallop, fleas have been a blight on humans and animals for over 100 million years. Like all parasites, these pint-sized pests depend on their hosts for their survival. When the host is your pet, and the little beasties are biting your ankles, it means war, and you'll do anything to get rid of them. Having a good grasp of flea biology and a few tricks up your sleeve to effectively kill flea larvae will help you win the battle.

Fleas are in the order Siphonaptera and are distributed worldwide. While most species prefer feeding on animals, many readily feed on humans, especially in a heavy infestation or when animal hosts are not available. It's estimated that 2,500 species of fleas exist, including human fleas, rat fleas, mouse fleas, poultry fleas, and even beaver fleas, but the vast majority found in American homes are cat fleas (Ctenocephalides felis) and, less often, dog fleas (C. canis).

Throughout the ages, fleas have been responsible for devastating epidemics of the plague in various places around the world, and still today, the Oriental rat flea (Xenopyslla cheopis), a parasite of rats in the genus Rattus, poses the most significant health risk to humans worldwide. Fleas cause a number of problems for our four-legged friends, too, and both the cat flea and dog flea are intermediate hosts of the dog tapeworm, which is common in both dogs and cats.

While ticks are more often associated with disease, fleas can also carry infectious bacteria that affect both animals and humans, according to PetMD, such as Bartonella henselae, also known as cat scratch disease, Mycoplasma haemofelis, and murine typhus. Also, if your pet is hypersensitive to flea bites, irritating and persistent allergies may develop. In young animals with immature immune systems, fleas can be potentially fatal.

Fleas have a complete metamorphosis, also known as holometabolism, a form of insect development which includes four distinct life stages: egg, larva, pupa, and imago or adult. This life cycle contributes to the survival of an insect species since the adults and larvae, being different, have different predators and do not compete for the same food sources.

The female adult flea sheds eggs in the environment that hatch into larvae after three to four days. Unlike other parasite eggs, flea eggs aren't sticky, and when laid on a host, they will usually fall to the ground. Round or oval in shape, flea eggs are white and are not easily observed by the naked eye.

Cat fleas have three larval stages, none of which live or feed on a host, but they instead eat the blood-infused feces of mature fleas and organic debris in the environment. The three larval stages can be completed in seven to 14 days depending on the temperature, humidity, and food availability. Look for larvae in and around your pet's bed. They are identified by their tiny (2.5 millimeters or 0.0984252 inches) worm- or grub-like appearance, and they have no legs or eyes.

While larvae can survive without food for a few weeks, the last larval stage does require food before molting into the nonfeeding pupal stage. Fleas in the pupal stage can survive for several months inside your home and quickly emerge into adults when they feel the vibration of an approaching person or pet. Pupae are barely recognizable without a microscope because they are encased in a sticky cocoon that is covered with debris. Cat flea pupae usually develop into adults in about one to two weeks.

Adult fleas are wingless and typically about 1/8 inch long, oval, and reddish-brown, explains Purdue University Medical Entomology. Once adult fleas emerge from their puparia, they have approximately seven days to find a blood meal, or they die. Once they've had the first blood meal, they can live up to 100 days without a meal.

Fleas are prolific, and a single female flea can lay 25 to 40 eggs per day, or more than 2,000 eggs in her lifetime, which is typically about 21 to 28 days. Adult female fleas are larger than males, and both are blind and have no ears.

Killing flea larvae goes a long way toward reducing an active flea infestation in your home. Of course, you still must also eradicate the adult fleas that comprise a typical swarm, often numbering in the thousands.

To focus on eliminating flea larvae, you should vacuum every day or at least every other day, using your crevice tool to suck up fleas, eggs, pupae, and larvae from the dark nooks and crannies of carpets, loose rugs, sofas, cracks between hardwood flooring, and where walls meet floors, and then discard the vacuum bag. You can also spread a thin layer of human grade-E diatomaceous earth over the surface of carpets and let it sit for 48 hours — keeping your pets off the carpet — and then vacuum thoroughly. The DE dries out the eggs, thus killing them, says Dogs Naturally. Alternatively, you can use coarse salt or baking soda for the same effect.

When you discover a flea infestation, toss dog beds, towels, pillows, blankets, and stuffed dog toys into the washing machine on hot and then into a hot dryer for at least 20 minutes to dry. Machine washing everything you can as often as possible kills flea larvae, thus controlling the flea population. A steam cleaner is also an extremely effective tool in your flea control arsenal. Steam clean your carpets once a month and use it on your upholstered furnishings too to drown fleas at every life stage.

Many swear by their natural flea eliminators, and one of the most popular concoctions is a flea spray consisting of four liters of vinegar, two liters of water, two cups of lemon juice, and one cup of witch hazel mixed together in a large spray bottle and then applied in a heavy spray to furnishings, pet beds, carpets, floors, and other areas where fleas congregate.

In a nutshell, flea larvae, pupae, and eggs make up about 95 percent of the flea population in an infested home, with 5 percent adult fleas — the ones that are feeding on your pets and perhaps biting your ankles.

Keep in mind that only adult fleas take blood meals, and neither the larvae nor the mature stage of fleas live on your pet but rather lurk in the dark cracks and crevices of your home, such as hardwood floors, upholstered furnishings, rugs, and carpets. The adult flea only jumps on a host for dinner and can consume 15 times its body weight throughout its 10 to 15 blood meals each day.

As a rule, you'll find flea larvae in and around your pet's bed but not on your pet's body. Once you know fleas are on the move, you can start treating your dog with an old-fashioned bath using organic, chemical-free, and sulfate-free shampoo, says Dogs Naturally. Lather well and let it sit in the coat for a bit and then follow up with an apple cider vinegar rinse consisting of 4 ounces of warm water to 6 ounces of apple cider vinegar and 1/4 teaspoon of sea salt. Shake well and spray it over his entire body, avoiding the eyes, and once dry, go over the coat with a fine-toothed flea comb to catch any stragglers.

When you're battling a flea infestation on your own, it sometimes may feel like you're getting nowhere. After all, it only takes a few weeks for a flea population to reach astronomic proportions. Don't dismay. Like all pest issues, elimination is a process, and it takes some time to become flea free.

However, if you feel overwhelmed and think your flea infestation may have grown unmanageable, consider calling in a licensed pest control professional who should be able to guarantee the successful elimination of fleas.