We love insects and other small invertebrates here at the Saint Louis Zoo, but we don't always enjoy sharing our home with them or having them bite or sting us! So here are some ways to control many common household pests without using lots of toxic chemicals.

Pests in Your Home

German Cockroaches
Although we may not welcome them, German cockroaches are an important part of natural ecosystems. They're a major food source for many other animals and are important recyclers in nature. But these little insects often find their way into our homes, and will eat just about anything they find, from bread and sugar to paint and paper! If you don't want roaches around, here are some tips to control them:

  • Eliminate their sources of food and water by routinely cleaning up food crumbs on counters, floors and garbage cans.
  • Store food, including foods in cabinets, in air-tight containers.
  • Seal crevices with paint, caulk, or putty.
  • If all else fails, use bait traps with chemicals such as boric acid powder.

Brown Recluse Spiders
Spiders can help humans by ridding our homes of cockroaches and other insect pests. But not everyone can tolerate spiders in their living areas, especially brown recluses!

The venom from a brown recluse spider bite affects different people in different ways. Reactions to a bite include the formation of a blister surrounded by a large swollen area, as well as fever, chills, and nausea. However, this spider is not aggressive by nature and normally bites only when disturbed. To deter brown recluse spiders from living in your home:

  • Inspect and shake out clothing, bedding, and towels before use.
  • Install screens on doors and windows and seal cracks and crevices.
  • Use sticky traps under furniture.

Carpenter Bees
Like many bees, the carpenter bee is a helpful pollinator of many plants. But it's not so helpful to humans when a female carpenter bee chews into porch posts and other wooden portions of our homes (even though they do this in order to build a nest, not to destroy our buildings)!

To stop any structural damage that may result from a carpenter bee's nest-building, you might try the following:

  • Make sure all wooden structures are free from rot and decay, since the bees usually choose soft wood to bore into.
  • Sprinkle diatomaceous earth into the nests after the bees have emerged for the day.
  • Fill any existing holes with wood putty, then paint over it.

Confused Flour Beetles
Both the larvae and the adults of these small beetles are common pests of kitchen pantries, where they infest flour, cornmeal, rice, and breakfast cereals. These insects do play an important recycling role in nature -- they help decompose dead plants and animals, which are returned to the soil as valuable nutrients. But if you'd like to keep your home free of confused flour beetles:

  • Locate the source of your infestation and throw out the food item.
  • Keep flours, grains and other long-term food items in insect-proof containers (glass, heavy plastic, or metal). Or refrigerate them.

Book Lice
As its name implies, the book louse enjoys snacking on the glue and molds found in old books. It also feasts on molds associated with cereals, furniture stuffing, and wallpaper. On the plus side, these animals also feed on dead insects and decaying plants, thereby contributing to natural recycling. To prevent an outbreak of book lice in your home:

  • Use a dehumidifier or fan to dry and ventilate any damp areas.
  • Store boxes, books, and papers off the floor.
  • Place already infected books in a freezer for a time.
  • If all else fails, you may want to try an insecticide such as pyrethrin.

Little Black Ants
Your house may be home-sweet-home for these little critters, which impose on your hospitality by eating your sweets, meats, and vegetables. Thought they may be unwelcome in our homes, ants play an important role in nature by mixing soil, destroying plant-eating insects, and distributing seeds. To control ants in your home:

  • Locate and destroy the ant colony. (Note: it may be in your garden, not your house.)
  • To destroy the ants' foraging trails, try rubbing them with soapy water or applying a pyrethrin spray or dust.
  • Clean up food crumbs on counters, floors and garbage cans.
  • Store food in air-tight containers.
  • Fix plumbing leaks.
  • Clean out dirty crevices

House Flies
Can we say anything good about the pesky house fly? Yes! The larval form of flies -- known as maggots -- play an important ecological role as decomposers of rotting plants and animals. Of course, that doesn't mean we want house flies in our homes. To keep them out of your house, try the following:

  • Make sure all windows and doors that you open regularly have good-fitting screens; also fill in cracks and crevices where flies might enter.
  • Remove materials where fly larvae can develop. Indoors this can be sources of rotting garbage; outdoors it can be organic waste such as pet droppings and rotting fruit.
  • For small numbers of pesky flies, install fly traps like sticky papers and ribbons or inverted cone traps. The time-tested fly swatter is an effective tool -- just be sure you don't kill a fly near food prep areas, since their body parts can infect food.
  • If you've exhausted all other options and are still infested, use a pyrethrin spray.

Pests on You

At least $1billion dollars a year -- that's how much pet owners spend to control fleas! They plague our dogs and cats, and sometimes even us. When a flea can't obtain a blood meal from its usual animal host, it may turn to humans for nourishment. Flea bites can cause a number of medical problems, from skin irritations and tapeworms to (worst case) bubonic plague. Though they may cause problems for humans and their pets, fleas in nature are an important food source for other insects, such as ants and beetles. To rid your home of fleas:

  • Vacuum carpets, and clean pet bedding frequently.
  • Keep fleas from hitching a ride on your pet by using special collars, drops or oral medications that break the insects' life cycle. Contact your veterinarian for pet treatments.
  • If fleas have already infested your home, you might use pyrethrin sprays and "flea "bombs" or foggers (with growth inhibitors) in selected rooms. This should be done at the same that you treat your pet, to prevent re-infestation.
  • You might also treat pet kennels, beds and other areas frequented by your dog or cat. Sometimes it might be necessary to treat larger portions of your yard.
  • If all else fails, contact a professional pest controller.

Head Lice
Anyone can acquire head lice. Intense itching of the scalp is usually the first sign of an infestation. Lice are spread by direct contact with an infected person or via infested items such as hats, combs, and bedding. (They cannot live on pets.) Lice are not known to spread any infectious diseases, and they pose more of a nuisance than a health hazard. To help prevent head lice:

  • Teach children not to share hats and combs, and to resist the temptation to try on hats at stores.
  • Shampoo often.
  • If you suspect a child is infested, keep him or her home from school. Look for nits (egg cases), which are silvery and about the size of the period at the end of this sentence.
  • In the case of an infestation, contact your doctor, pharmacist, or local health department for proper treatment procedures. These may include use of a special insecticidal shampoo, removing nits from the head (usually with a nit comb), removal of nits from bedding and home by vacuuming, washing and freezing infected items, and daily head checks and nit removal until the infestation is gone.

A tick can sense an approaching host from up to 500 feet away! Once aboard its host, the tick crawls upward, seeking a good spot to take its meal of blood. While most ticks are merely annoying, some are carriers of serious illnesses, such as lyme disease. If your tick bite develops a red, ring-like lesion, it may be an early sign of lyme disease -- contact your doctor immediately. To control ticks near your home:

  • If you're walking in tick-infested areas, try to wear long pants and a long-sleeved shirt. Tuck your shirt into your pants, and tuck pant legs into boots or socks.
  • Inspect your pets and children (and yourself!) for ticks after they've been in known tick habitat. Common areas to find ticks on people are on the scalp, behind an ear, or in the crevices of arms and legs.
  • If you find a tick, remove its entire body from the skin with tweezers or your fingers, wash the area, and apply a topical antiseptic.
  • Consider applying topical tick repellents to you and your pets the next time you enter tick habitats. Sweat and water can wash off repellents, so re-apply as needed.

For most of us in this country, a mosquito bite is a minor irritation. But in some parts of the world certain types of mosquitoes spread yellow fever and malaria. While they are nothing but trouble for humans, mosquitoes are an important food source for other insects, and for many birds and fish. To control mosquitoes:

  • Eliminate standing water around your home where mosquito larvae can develop. Change the water in your bird baths and pet bowls at least once a week.
  • Make sure your windows and doors have tight-fitting screens.
  • Make use of citronella candles and other non-toxic repellents. Some sprays and foggers are useful against adult mosquitos when used before outdoor parties, but their effects are only temporary.
  • Minimize your exposure to mosquitoes by staying indoors at times when they're most active (often early evening). If you have to be outside, cover your skin with long pants, long-sleeved shirts and a hat.
  • Apply a topical mosquito repellent on your skin when you know you'll be staying outdoors during mosquito season. Products containing DEET are often effective, but their effects are only temporary. Re-apply as needed.

Bed Bugs
"Don't let the bedbugs bite!" Bed bugs come out at night to feed on blood (usually of mammals). Although they're not usually considered to be disease carriers, their bites can cause severe itching. They are seldom seen, but bed bugs do leave traces: dark spots of fecal matter, bloody spots on sheets, and an offensive odor. To prevent and control bed bugs:

  • Launder your bedding regularly and vacuum bedrooms frequently.
  • Caulk cracks and crevices in the house.
  • The only safe way to eliminate these pests once they've infested your home is with a residual pyrethrin spray. This is usually a job that should be done by a qualified pest control expert.

Pests in Your Yard

Tomato Hornworms
You may have encountered this caterpillar in your vegetable garden. While tomato plants are their food of choice, they may also eat eggplants, peppers, and potatoes. In large numbers, caterpillars can cause severe damage in a short period of time. To control tomato hornworms in your garden:

  • Pick hornworms from plants.
  • Because parasitic wasps feed on and eventually kill hornworms, do not kill wasp-infested hornworms. Wasp cocoons appear as white projections on the hornworm's body.
  • As a last resort, try a natural product containing Bacillus thuringiensis, known as "Bt".

Time for some grub! These little critters -- the larval stage of beetles -- will feed on grass, grass roots and crops. Their huge appetites can result in extensive damage to your lawn and garden. They may be pests to people, but grubs provide a good food resource for skunks, moles, crows, and blackbirds. To control grubs:

  • Maintain a well-watered, fertilized, and aerated lawn to help it resist a grub attack.
  • Plant geraniums in your garden to repel grubs.

These are garden "good guys" -- you don't want to get rid of them in your garden; you want to attract them! The pretty little ladybug consumes huge numbers of plant-eating insects such as aphids. In fact, one ladybug can eat up to 5,000 aphids in its lifetime! But if ladybugs come into your home, they can become a nuisance. Try the following:

  • Seal cracks and crevices to discourage their entry.
  • Gently move them outdoors.