The Master Gardener clinic at the WSU Extension office is not only a resource for gardening questions but also for garden pests and other insects. No one likes these unwanted visitors, so we first try to identify them and then suggest measures for natural control or elimination.
When it starts to turn cold outside, many insects search for a warmer habitat. Lately we have seen the reemergence of fleas (Siphonaptera). We always think of fleas as warm-weather insects. In reality, fleas do not need warm weather, they just need a warm body!
Almost every pet owner we know has fought a few rounds with fleas. They are external parasites living on warm-blooded animals. Adult fleas are wingless, with mouth parts adapted for piercing skin and sucking blood. Interestingly, a flea can jump vertically up to 7 inches and horizontally up to 13 inches. Their body is compressed laterally, hard, polished, and covered with many hairs and short spines directed backward, which helps in moving through their host’s hair and fur.
Fleas are nest parasites, meaning they move between host animals — cats, dogs, etc., and their bedding. Normally a flea’s population would consist of 50% eggs, 35% larvae and 10% pupae — with the remaining 5% being adult fleas. When there is a flea infestation, eggs, larvae and pupae can be found in pet bedding, carpets, rugs and upholstered furniture where pets sleep.
Adult fleas are not good climbers, so they are mainly found on the host animal, on the floor or in bedding materials. Eggs are loosely attached to the host and can be jarred loose onto carpets when the host is active. The larvae are small, whitish, worm-like and feed on adult flea fecal matter. This fecal matter is what we often notice on our animals with an infestation, as it appears like fine grains of sand in the fur.
Fleas can survive as a pupae for several months in uninhabited apartments and homes. Then when new inhabitants show up, they are greeted with a flea outbreak. This outbreak is triggered by pressure and vibration from footsteps, which stimulate the dormant fleas to literally jump out of their pupal cases and seek the closest host. In uninhabited homes, the flea population is composed almost entirely of immature fleas as pupae. So using controls aimed at adults will not eliminate the flea infestation in empty dwellings.
Due to environmental conditions in the Pacific Northwest, fleas in lawns are not normally a problem, so outside flea control is rarely necessary. The one exception might be the outdoor area of a kennel or a very small yard.
There are many nonchemical options for controlling fleas, and they should be used first.
• Bathe pets frequently but do not use products containing d-limonene, linalool or permethrin on cats.
• When using topical (skin applied) flea control products, be aware that frequent bathing may reduce the longevity and effectiveness of these products. For best results, apply topical products after baths and limit the number of baths.
• Do not use the old folk herbal remedy pennyroyal, which is considered toxic, especially to pregnant animals.
• As a last resort, use a flea comb and comb through your pet’s hair/fur, then drown the fleas caught by the comb in soapy water.
• Do not allow pets access to areas that might be infested, or to be around infested animals.
• Flea control in unoccupied houses and apartments is done with thorough vacuuming. The vacuum bag after use should be sealed in a plastic sack and disposed of in an outside container. Repeat this procedure later using a new vacuum bag. The vibrations from the footsteps and the vacuum will stimulate pupae to hatch into adults. You will want to tuck pant cuff into boots or socks, as you can get bites on your ankles from adults.
• If the home is occupied and the host animals are present, vacuuming will help somewhat, but will not be 100% effective; home treatment must be used in conjunction with pet treatments.
• Make sure you also vacuum upholstered furniture and wash (if possible) fabric items (pillows, beds, etc.), especially in areas where the pets routinely rest and sleep.
• Be sure to wash pet bedding frequently.
Now that you are totally upset, paranoid and checking out your pet(s) and their bedding for the presence of fleas, hopefully your home and your pets will be a cleaner place by putting these measures into practice.