How To Rid Your Home Of Cockroaches: In-Depth Facts & Control Methods

Cockroach

One of the things that sends shutters down the spine of most homeowners is to discover their home is infested with cockroaches. There are low cost, safe methods of ridding a home of cockroaches without having to use potentially toxic chemical sprays and bug bombs.

To safely and cost effectively rid your home of cockroaches you need to;

  • Understand the damage cockroaches do
  • The diseases cockroaches carry
  • Cockroach characteristics and life cycles
  • Cockroach management techniques
  • How and where cockroaches like to hide
  • How to safely use baits and dusts to eliminate cockroaches

A few years ago I took a course in Pest Management Technology and spent several years working in pest control. In this article I share what I learned from my study and experience in pest control about ridding your house of cockroaches.

Cockroach control and elimination is much easier when you have the basic knowledge and understanding of cockroaches found in this article.

Cockroach Damage And Health Implications

Cockroach presence may first be noticed when the damage they do becomes evident. Cockroaches can eat things such as glue or paste, starches and some dye colors. Thus their damage can become evident by the signs of their feeding on stamps, envelopes, the bindings of old books, drapery and even on wall paper.

Because cockroaches like to hide in damp germ laden areas such as sewers, garbage disposals, and damp unsanitary areas in kitchens and bathrooms they become a source of spreading germs found in these areas. When they come out to feed, the germs carried on their feet, legs and bodies can be left in food supplies and on surfaces such as counter tops and dishes.

Cockroaches contaminate much more food than they eat. In addition their bodies produce secretions that can impart a foul smell and taste to foods they feed on. These secretions, cockroach excrement called frass and even cockroach egg capsules, can be allergens that result in severe asthma attacks, skin rashes, watery eyes and sneezing.

Diseases transmitted by cockroaches include:

  • Food poisoning
  • Nausea and vomiting
  • Abdominal cramps
  • Diarrhea
  • Dysentery
  • Other illnesses

General Cockroach Characteristics

Cockroaches are primarily active at night. This is when they look for food, water and mates. That said, they may be seen in the daytime under certain circumstances such as when the numbers of them are very large or there is some form of stress. Some common forms of stress include lack of food and water and the presence of predator ants.

The preferred environment for cockroaches is a place that is moist and warm. The types of cockroaches usually found in homes and outbuildings are very fond of starches, sweets, grease and meat products. However, they will also feed on cheese, beer, leather, bakery products, starch in book bindings, glue, hair, flakes of dried skin, dead animals and plants.

Although not usually sociable in the same manner as ants, some bees, wasps and termites, some species of cockroaches can be found hiding together and feeding together.

Cracks and crevices where cockroaches can hide

Cockroaches are generally oval shaped and flat bodied. This allows them to squeeze into all sorts of cracks and crevices. They have long legs that allow then to run rapidly and special pads on their feet that allow them to walk up glass and across ceilings. They like to forage for food in garbage cans and garbage piles, sewage systems and septic tanks.

The development of cockroaches involves three stages; egg, nymph and adult. Female cockroaches lay eggs in an egg capsule. Nymphs hatch out of the egg capsule and undergo several molts before becoming an adult cockroach.

Nymphs resemble adults in shape but are smaller and may not have all the same color characteristics as adults. In those species that have wings, nymphs only develop fully formed wings with the last molt.

The time period for the eggs to hatch, the nymphs to develop and the life span of the adults depends upon several factors. These factors include temperature, humidity, the quality of the food they eat and other environment factors.

Different Types Of Cockroaches And Their Specific Characteristics

Cockroaches are one of the most common household pests. They can vary in size from about 1/2 " up to 2" or more in size. There are some 3,500 different types of cockroaches known to exist in the world.

One of the most common cockroaches found in houses in North America and many other areas of the world is the German cockroach. Some of the most common cockroaches found infesting homes include the:

  • German cockroach
  • American cockroach
  • Oriental cockroach
  • Brownbanded cockroach
  • Smokybrown cockroach
  • Australian cockroach
  • Brown cockroach
  • Woods cockroach
  • Field cockroach
  • Asian cockroach

In North America, the first five cockroaches listed above represent about 95% of all cockroach infestations in and around buildings. These 5 cockroaches will be discussed in some detail and there will be mention of important characteristics and differences of the other types of cockroaches listed above.

All female cockroaches produce egg capsules which consist of 2 rows of eggs containing from 16 to 48 total eggs depending upon the type of cockroach.

German Cockroaches

Adult male German cockroach

The adults of German cockroaches are pale to medium brown and vary in length from about 1/2" to 5/8" long. Adult German cockroaches can be distinguished from other kinds of cockroaches by two dark stripes on the top of their thorax, the first segment behind the head. Adult males and females have well developed wings but do not fly.

German cockroach nymphs look like adults but are smaller and dark colored with some being nearly black. They have a single light stripe running down the middle of their back and they are wingless.

Adult females carry the egg capsule sticking out from the back end of the abdomen. The German cockroach is the only type that carries the egg capsule until the nymphs hatch. If the egg capsule is not carried until hatching it must be in a place with at least 70% humidity or the capsule will dry out and the developing nymphs will desiccate and die before hatching.

Nymphs usually hatch from the egg capsule in 20-30 days, the shorter time is when the temperature is 77 degrees F (25 degrees C) or higher. The nymph stage involves several molts and takes anywhere from 40 to 125 days depending upon diet quality, whether the area is crowded with nymphs and adults and the temperature.

Nymphs, like adults are active mostly at night and hide in dark, preferably moist cracks and crevices during the day. When adult German cockroaches and nymphs are seen during the day time it means either the population is so large that the available cracks and crevices are already full or food and moisture are in such short supply that they have to forage in the daytime.

German cockroaches usually hide in or near the kitchen. They are particularly attracted to fermented foods and beer spills. If they can find water, adults can live about a month without food. Nymphs can only live on water for about 10 days. Without food or water adults die in less than two weeks.

American Cockroach

American cockroach - Periplaneta americana USA, TX, Travis Co. Austin 30.33ºN -97.75ºW 210m 17.iii.2016, indoors, A.L.Wild, coll.

Other names for the American cockroach include; waterbug, flying waterbug and palmetto bug. Adult American cockroaches can be 1 1/2" or more in length. They are reddish brown with a pale brown or yellow border of the thorax, the segment just behind the head.

At 70 degrees F, (21.1 degrees C), nymphs hatch from the egg capsule in 50-55 days. Unlike the German cockroach, American cockroach females do not carry the egg capsule but either drop it in a moist protected area outdoors or glue it to a fairly hidden surface, indoors or outdoors, using a secretion from the female's mouth.

The time to go from a nymph to an adult varies from 160-971 days depending upon environmental conditions. Once the adult stage is reached females can live for 14-15 months, males not quite that long.

When found indoors the adults and nymphs usually hide in dark, moist areas of basements, crawlspaces, around bathtubs, clothes hampers, floor drains and sewers. They may be found high on walls in corner areas of basements.

This variety of cockroach is more commonly found in large industrial buildings in northern climates. In southern climates they can be found in alleyways, yards, hollow trees and palm trees. They prefer moist shady areas and can be found near swimming pools. around foundations and under ground covers.

While primarily an outdoor variety, American cockroaches move indoors in search of food and moisture. Although they prefer decaying organic matter, they feed on book bindings, manuscripts, clothing, and glossy paper if those items contain starch. Syrups and sweets are other food items that attract American cockroaches.

Adult American cockroaches can live for 2 to 3 months without food and about a month without water.

Adults have well developed wings but rarely fly unless the temperature is above 85 degrees F, (29.4 degrees C). If they take off from a roof top or tree, they can glide long distances. In the US they have been reported flying short distances as far north as Kentucky.

Oriental Cockroach

Oriental cockroach

The Oriental cockroach is also called a waterbug, black beetle, and shad roach. It is common in all parts of North America except far northern climates. Adults are very dark brown or nearly black and have a greasy or shiny appearance. Females are about 1 1/4" long and males about 1" long.

Females deposit the egg capsule near a food supply but do not glue them to a surface. Nymphs hatch from the egg capsule in about 60 days under room temperature and conditions. Nymphs go through several stages of development that can take from several months to a year.

A peculiarity of Oriental cockroaches is that they have a seasonal developmental cycle. The number of adults peaks in late spring or early summer and reaches a low by late summer or early fall. If nymphs have not reached adulthood by late fall or early winter their development is slowed and it is next spring before they become mature adults.

Nymphs and adults can be found where ever there is decaying organic matter indoors or outdoors. This includes yards, underneath leaves, in stumps, in crawlspaces, mulch in flower beds and landscape retaining walls. They can be common in high moisture areas such as sewers, water meter enclosures, drains, and dark damp basements.

Both adults and nymphs are somewhat sluggish and are usually found at or below ground levels indoors. They are rarely found on walls, in high cupboards or upper floors of buildings. They may be found in bathtubs because the pads on their feet are so small they have a hard time walking up slick walls.

Oriental cockroaches feed on all kinds of filth, rubbish and decaying organic matter. If they have water they can live a month without food, but only 2 weeks without water. In many parts of the country they are found outdoors in warm weather but move indoors as cold weather approaches. In periods of drought, they move indoors in search of moisture.

Brownbanded Cockroach

Brownbanded cockroach

Brownbanded cockroaches are one of the smaller cockroaches and are rarely more than 1/2" in length. They are identified by 2 lighter bands running from side to side across the abdomen of adults. On nymphs the 2 bands may appear somewhat broken.

Males and females are very active and may jump when trying to escape. Males can fly when disturbed. They are commonly found inside the same buildings that harbor the German cockroach.

Females usually attach the egg capsule to a protected surface. Nymphs hatch in about 50 to 75 days depending on the temperature. Under normal room conditions nymphs reach adulthood in about 160 days. Adults can live up to 10 months.

Both adults and nymphs are usually found high on walls, behind picture frames and light fixtures and near the motors of refrigerators and other appliances. They can also be found inside wall light switches, closets and even furniture.

They do not have to be as close to a source of moisture as German cockroaches so are commonly found in rooms other than kitchens and bathrooms. Brownbanded cockroaches have a strong aversion to light and are not normally seen in the daytime.

Brownbanded cockroaches prefer eating starchy materials but have been found feeding on just about anything. They chew on non-food material such as nylon stockings because of the residue of body oils and skin flakes found there.

These cockroaches have been found as far north as Canada. But in northern climates they usually are only found in the warmer parts of buildings.

Smokybrown Cockroach

Smokybrown cockroach

Smokybrown cockroaches are a close relative of the American cockroach. They are distinguished from the American by being smaller, slightly longer than 1", and having a solid mahogany color. Males and females have wings longer than their bodies.

Females usually glue their egg capsule to a surface but they may be found lying on the ground. Nymphs hatch and develop into adults in a manner similar to the American cockroach. Adults can live from 200 to 300 days at room temperature.

In North America Smokybrown cockroaches have a limited distribution. It is found from central Texas eastward along the Gulf Coast, from Florida up the eastern seaboard and in some areas of southern California. It is an outdoor cockroach that moves into and out of buildings as it needs to forage for food and moisture.

It's main food source is plant material. It is found in many greenhouses. But it can feed on almost anything other types of cockroaches eat once inside a building. It is usually found living under wood shingle roofs and in gutters where there is an abundance of decaying organic matter. It can also be found living at the roof-line in attics.

In the southern portions of the US many homes are sided with brick. These homes have weep holes in the brickwork to allow for moisture collected between the bricks and the walls to escape. These weep holes are a route for cockroaches and other insects finding entrance into wall voids.

Woods Cockroaches

Pennsylvania Woods cockroach
Happy1892 [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]

The name Woods cockroach is given to several types of cockroaches that have similar habits. In the US it is most commonly referring to the Pennsylvania Woods cockroach. These cockroaches are small, commonly about 2/3" long. Adults are dark brown in color with the thorax and front half of the wings trimmed in yellow.

Male Woods cockroaches have wings that are longer than their body and female Woods cockroaches' wings are 1/3 to 2/3 the length of their bodies. The males are good fliers and the females do not fly at all. In North America they are found in the eastern US, southern US and mid-western US all the way up to Canada.

These Woods cockroaches are primarily outdoor cockroaches and their egg capsules are laid behind loose bark of dead trees, fallen logs or stumps. They almost never breed indoors. Nymphs and adults are commonly found beneath loose bark of woodpiles, stumps and hollow trees.

Woods cockroaches can be brought into homes with infested firewood. They will wander around the house without showing a preference for any particular room. May and June, their usual mating season, is when they can be the most troublesome. Males are readily attracted to lights and can gain entry indoors when people go in and out.

They may be found in fairly large numbers in and around rain gutters. They feed mostly on decaying organic material such as plants and leaves.

Australian Cockroach

Australian cockroach
charliebrewer [CC BY-SA 2.0 (https://creativecommons.org/licenses/by-sa/2.0)]

Australian cockroaches appear a lot like American cockroaches. The differences are; they are only about 1 1/4" long, coloration is reddish brown with prominent yellow stripes on the outer edge of their wings and a dark spot in the center of the segment behind the head. Both males and females have well developed wings that cover their entire body.

Egg capsules are left in cracks and crevices and nymphs hatch in about 30 days. Nymphs have yellow splotches on their back and undersides. Both nymphs and adults can be found under loose bark and decaying vegetation.

Australian cockroaches are usually found in the southern portions of North America but have also been found in greenhouses and homes in northern States where plant material and moisture is present. They feed on plant materials and starchy materials in homes.

Brown Cockroach

Brown cockroach
Caroline Harding, MAF Plant Health & Environment Laboratory [CC BY 3.0 au (https://creativecommons.org/licenses/by/3.0/au/deed.en)]

Brown cockroaches are similar to American cockroaches except there is almost no yellow markings on the thorax. Their coloration is dark reddish brown and males and females have well developed wings and a wider body than American cockroaches.

In North America they are found in the southern US from Florida to Texas but are sometimes found as far north as Philadelphia, Pennsylvania and Columbus, Ohio. They can be found indoors and outdoors usually beneath tree bark, in sewers, garbage piles, crawlspaces and other similar areas. They especially like to live in Palm trees.

Egg capsules can be found glued to walls near the ceiling in open spaces in homes and businesses. Outdoors the egg capsules are usually dropped in protected areas near moisture or decaying plant material.

Field Cockroach

Field cockroach
Sam Kieschnick http://www.inaturalist.org/photos/4555415

A Field cockroach is slightly smaller than the German cockroach. Field cockroaches have a blackish or tan area on the front of the head and a different color pattern underneath the wings than German cockroaches.

In North America they are found from California to Texas. They are normally outdoor cockroaches that feed on decomposing vegetation. They can be found in irrigated areas, under stones, clumps of dirt and similar types of locations.

Females carry the egg capsules until they are ready to hatch then drops them outdoors. They can come into homes during dry spells and wander about the walls and floors during the day time. They make no effort to hide in dark cracks like German cockroaches do.

Asian Cockroach

Asian cockroach

The Asian cockroach is native to areas in southeastern Asia but appears to have been introduced to the US through the port city of Tampa, Florida. It has become a common pest throughout central Florida with the potential to spread to other areas of the US that have a similar climate as central Florida.

Asian cockroaches are similar in looks to German cockroaches but have different behavior. They seem to like living in shaded, moist areas that are landscaped, in grassy areas and ground covers.

They are most active just at dusk and remain active for a few hours. The adults fly easily and travel long distances. They readily fly to lights and enter homes and become a special nuisance by landing on TV screens and people. They appear to be particularly fond of disrupting backyard barbecues and patio parties in the evening.

Cockroach Management Techniques

Effective and safe nontoxic chemical cockroach management involves more than just using dusts and baits. The most effective non-chemical cockroach management can involve four areas:

  • How to do a proper inspection
  • Why sanitation is necessary
  • Proper techniques to exclude roaches
  • Safe and effective control methods

How To Do A Proper Inspection

The purpose of a cockroach inspection is to locate as many hiding, (harborage) areas for cockroaches as possible. The most successful attempts at cockroach eradication come after a thorough inspection and treatment of all located and suspected cockroach hiding places.

Inspecting for cockroaches with mechanic's mirror and flashlight

A successful cockroach inspection requires the use of a very bright flashlight (link to read reviews on Amazon), a mechanic's mirror (link to read reviews on Amazon) that allows seeing areas hard to see otherwise, screwdrivers, pliers and other hand tools to remove panels on equipment to see if cockroaches are hiding inside and knee pads (link to read reviews on Amazon) and a hard hat (link to read reviews on Amazon) to protect the inspector's head from bumps as he is looking for cockroach hiding places.

View from an human's perspective

When inspecting for German and other cockroaches that commonly inhabit buildings it pays to think like a cockroach. This thinking process requires being close to the floor in order to see cracks and crevices where a cockroach could hide. Eyes that are 5 to 6 feet above the floor can't see the cracks and crevices that make good hiding places for cockroaches.

The cockroach sees plenty of good hiding places

But, do not forget that cockroaches can also climb walls and some types of cockroaches will hide inside light fixtures on the ceiling. So a thorough cockroach inspection can also require a stepladder to be able to get up close to light fixtures to see if there are any cracks around the light fixture that a cockroach could squeeze through to hide.

It is even a good idea to conduct an inspection at night. That is when most cockroach types come out of hiding to look for food, water and mates. German cockroaches scatter when a bright white light is shown on them. There is a yellow filter that can be put over flashlight lens that does not startle German cockroaches and allows better observation of their behavior and hiding places.

One thing to keep in mind when inspecting for cockroaches is they have a trait called thigmotaxis. That means they prefer to have a side or the top of their body touching something else. So they tend to travel along walls and furniture much more than out in the open portions of a room.

Why Sanitation Is Necessary

After inspection, the next important aspect of treatment for cockroaches is sanitation. Sanitation removes cockroach sources of food and moisture thus stressing the cockroach population which makes the elimination efforts with baits and dusting, (discussed later in this article), much more successful.

All food storage areas should be inspected. Cupboards, pantries, especially storage shelves in basements or other areas not usually looked at by people other than to go for a specific item or to place a purchased item in storage. These areas can have cockroach damage to boxes and bags of food that can only be seen by a thorough inspection.

Any spills of food such as flour, sugar, etc should be completely cleaned up and any damaged food containers thrown away to remove that item as a food source.

If it was something that was a liquid or a grease based food the area should be cleaned with soap and water, rinsed with water using a different cleaning cloth than the one used with soap and water and thoroughly dried before replacing undamaged packages of food back in storage.

Do not forget to inspect areas where pet's food is stored and clean any spills and remove damaged containers as described above.

Rigorous sanitation places a lot of stress on German cockroaches and other cockroach populations. When highly stressed cockroaches forage more actively and are more readily controlled by baits and dusts than when the sanitation step is skipped.

Proper Techniques To Exclude Roaches

Exclusion techniques include caulking cracks and crevice entrances to limit the routes cockroaches use to get into your home. When combined with high levels of sanitation, exclusion techniques can reduce the number of cockroaches accessing your home before you even use baits and dusts to kill cockroaches!

The best caulk to use is a caulk that will stick to the surface being caulked. To seal cracks and crevices in kitchens and bathrooms Tub and Tile Caulk (link to read reviews on Amazon) is a good choice because it is formulated for areas that can get wet and have a higher moisture content. Some brands also include an adhesive in the formula. These caulks clean up with water and can be painted over.

In areas other than kitchens and bathrooms an Acrylic Latex Caulk is a good choice. It adheres to most surfaces, even masonry, is easy to apply and cleans up with water. This Acrylic Latex Caulk made by Dap (link to read reviews on Amazon) would be a good choice to use. I've always found Dap brand caulks to be very good products.

The best exclusion formula to use where pipes enter the house, around electrical outlet and switch boxes, and in gaps, holes and voids is Polyurethane foam (link to read reviews on Amazon). It expands to fill gaps, is easy to apply, cures readily, has good adhesion and is paintable.

Another exclusion technique is to use sticky barriers such as rodent glue boards (link to read reviews on Amazon) or insect trap adhesives (link to read reviews on Amazon). These can be used to keep cockroaches from climbing up table legs, furniture legs or in some instances even from climbing up on counter tops.

A useful form of exclusion is a sticky spray (link to read reviews on Amazon). This could be sprayed on table legs or on the legs of metal tables to prevent cockroaches from getting on top and contaminating the table top by walking on it.

Some people have found that Teflon sprays (link to read reviews on Amazon) that leave a dry powdery film on treated surfaces also work to keep cockroaches from climbing up onto tables, counters and furniture. They spray it on the furniture's legs, table legs or sides and toe space portions of cabinets. Be aware that it will leave a powdery film that can be white in color.

One form of exclusion that you should avoid are electromagnetic, sonic or ultra sonic devices sold to make cockroaches and other pests leave the premises. By and large, these devices do not work and are a waste of money.

Safe And Effective Control Methods

This is the portion of cockroach elimination that makes the best use of what was learned during the inspection phase. In the control phase, either dusts or baits are used depending upon the types of areas identified in the inspection phase as cockroach hiding (harborage) areas.

The primary thing to remember when treating for cockroach control is that baits or dusts placed directly into or very near harborages will always produce better results than when they are placed where cockroaches might walk over them or find them only occasionally.

There are two kinds of dusts that if placed into or very near those areas where cockroaches hide that can be effective in controlling cockroach populations. Those dusts are boric acid and diatomaceous earth.

Boric Acid When Used In A Bait Formulation

Boric acid when used in a bait formulation, more on this in a moment, is a poison that kills by upsetting the insect's metabolism. When used as a dust or dry powder, boric acid has an effect like tiny shards of glass cutting the cockroaches apart. This effect does not happen immediately which can allow that cockroach to make it back to it's nest before it dies.

Since cockroaches are cannibalistic, those roaches that eat the cockroaches that died from either ingestion of or walking through boric acid will eat the powder trapped on or in the dead roaches and die from consuming boric acid still on or in the dead roaches!

Boric acid (link to read reviews on Amazon) is much safer to use around people and pets than the toxic chemical sprays of most insecticides.

In fact boric acid is roughly as toxic in large amounts as table salt. The LD50 value of Boric acid, (Lethal Dose required to kill 50% of those exposed to it), is 0.49 pounds (212 grams for an 176 pound (80 Kg) human. For the same size human 0.52 pounds (240 grams) table salt is the equivalent LD50 dose. (dengarden.com/pest-control/boric-acid-toxicity...)

"The minimal lethal dose of ingested boron (as boric acid) was reported to be 2–3 g in infants, 5–6 g in children, and 15–20 g in adults. […] However, a review of 784 human poisonings with boric acid (10–88 g) reported no fatalities, with 88% of cases being asymptomatic."

HHS, Public Health Service, Agency for Toxic Substances and Disease Registry (November 2010), Toxicological Profile for Boron (PDF), p. 11

Nevertheless it is important to use boric acid only in locations or in a form that will not attract children and pets to limit the chances of problems with their exposure to boric acid.

You can use boric acid as a barrier or perimeter treatment if you sprinkle or puff a fine layer of the dust all around the perimeter of your home. Any cockroaches crawling through this barrier will collect some on them and die. Do not make a small pile of boric acid powder. Roaches will see it and walk around it instead of through it!

Boric acid preparations such as Zap-A-Roach Roach & Ant Killer come with a tip that allows you to puff it around the house's perimeter and into cracks, crevices or voids where cockroaches hide. When puffing it into cracks, crevices or voids take care not to breathe some of the dust. It could make you cough or cause an asthma attack if you are asthmatic.

Boric acid powder will need to be replaced outside after a rain or inside if the area collects moisture or gets wet. Boric acid powder does not cut up roaches like little shards of glass when it gets wet.

Making Boric Acid Roach Baits

You can make your own Boric acid roach baits if you are so inclined to do so. Here's a couple of recipes for Boric acid roach baits.

Mix together:

  • 1 cup maple syrup
  • 2 cups boric acid powder (link to Amazon)
  • 4 teaspoons flour to thicken

After mixing, stir well. The result will look somewhat similar to peanut butter. Spread some of this mixture using a butter knife or popsickle stick beside those areas you determined were hiding places for cockroaches when you did the inspection of your home.

This cockroach bait looks like peanut butter and smells like maple syrup. This means it can be attractive to toddlers and pets, especially dogs. So do not place it where toddlers and dogs can get to it and eat it! This could mean you caulk areas around baseboards to exclude cockroaches instead of spreading this maple syrup boric acid bait along baseboards!

Here is another cockroach bait recipe.

Ingredients:

  • 2 tablespoons solid vegetable shortening or lard
  • 1/2 small onion finely diced
  • 1 teaspoon sugar
  • 2 tablespoons boric acid powder

Directions:

  1. Finely dice 1/2 small onion, about 3 tablespoons, and place into a small mixing bowl
  2. Add the shortening or lard, sugar and boric acid to the bowl of onion
  3. Mix very well with a metal fork
  4. Place 1/2 teaspoon of mixture in an old jar lid using a metal spoon
  5. Place this bait dish in back of cupboard, behind appliances in kitchen, behind washer/dryer in laundry room, in back of cabinet under sink in bathroom, and in inaccessible areas of garage where roaches were seen
  6. Replenish bait as needed

If no indoor pets or toddlers who could get to it, sprinkle some behind furniture near areas where cockroaches were seen during inspection.

Spread it along areas inaccessible to pets and toddlers where inspection found potential roach hiding places. As long as it does not get wet or vacuumed up from behind couches it can be effective.

Using Diatomaceous Earth As A Dust

Food Grade Diatomaceous Earth (link to read reviews on Amazon), DE, used as a dust is also effective in ridding your home of cockroaches. DE is the shell of one celled organisms called diatoms, a type of algae. The shell has small sharp spines on it and these spines penetrate the waxy exoskeleton of bugs such as cockroaches and causes them to die from desiccation, dehydration.

The spines on Food Grade Diatomaceous Earth, although very sharp, are so fine they do not pierce human skin so DE is safe to use around humans and other mammals. More information on DE and how to make a DE puffer from a plastic mustard container can be found in this article that I wrote.

Puff DE into cracks, crevices and voids that have been identified or suspected as harborage for cockroaches. Also puff some DE near these harborage areas and as cockroaches crawl through it some will adhere to their bodies causing death. They will also take some DE back to their nest causing other cockroaches to come in contact with it and die.

Breathing DE can cause coughing or breathing problems if you have asthma. When DE gets wet it becomes soft and the spines will not penetrate the waxy covering of hard shelled bugs like cockroaches. So if the area treated with DE gets wet, after it dries, DE will need to be reapplied.

Diatomaceous Earth takes a little longer to kill cockroaches than Boric acid does. But Food Grade DE is not harmful to pets and toddlers who might come into contact with it.

More than 170,000 tons of diatomaceous earth are used in the filtration of food products annually. For these reasons the FDA has granted GRAS, Generally Recognized as Safe, status to filtration media containing diatomaceous earth. No acute toxic reactions have been reported from ingestion.

https://www.livestrong.com/article/510749-dangers-of-taking-diatomaceous-earth-internally/

Caution About Diatomaceous Earth

Do not confuse Food Grade Diatomaceous Earth with Pest Grade Diatomaceous Earth or Filter Grade Diatomaceous Earth. Food Grade DE will kill insects just fine. Pest Grade DE has added chemicals to attract insects. When Food Grade DE is placed at or very near where a good inspection has shown bugs such as cockroaches to be hiding the Food Grade DE works just fine.

By not purchasing Pest Grade DE you eliminate the possibility of confusing Pest Grade DE which has harmful chemicals in it with Food Grade DE which contains no harmful chemicals.

Filter Grade DE is calcinated, heat treated, which changes it from amorphous DE, safe DE, to crystalline DE which is not effective for use as a bug killer. Filter Grade DE, crystalline DE, has a crystalline form of silica that if inhaled can cause silicosis or even lung cancer. Filter Grade DE's only use is in water filters, mainly for swimming pools.

Specific Cockroach Management

Cockroach management is not a one method fits all technique. Different types of cockroaches have different living patterns and habits. Knowing these living patterns and habits and using them against the cockroaches can greatly improve your chances of completely eliminating a cockroach problem.

Specific pointers on cockroaches and methods that help eliminate specific types of cockroaches will be discussed now.

German Cockroaches

German cockroaches are usually found near sources of food, water and warmth indoors. Especially when they are in the small nymph stage. The adult males and larger nymphs will range more widely in an infested home. The adult females will forage for food and water but when the egg capsule is being carried they leave the harborage area only rarely and usually to find water.

When an infestation of German cockroaches is known or suspected it can not be overemphasized that the inspection phase should be done thoroughly. Failure to preform a thorough inspection is one of the primary reasons for failure to rid your home of German cockroaches.

Specifically look for cracks, crevices and voids within or between areas of construction such as walls, baseboards, toe spaces under cabinets and areas where add-ons to the home have been made. Other places to look include under tabletops, behind and under sinks, inside cabinets, in motor compartments of refrigerators and freezers, in light switch and wall plug boxes, vegetable bins, even inside hard line telephones.

Use of one or both of the above Boric acid baits placed in cracks and crevices can be very effective. When placed here they are placed exactly where the insect spends most of it's time hiding.

Use of Boric acid powder or Food Grade Diatomaceous Earth as dusts (by puffing) in dry areas where German cockroaches are suspected of hiding is actually more effective long-term than insecticide sprays which loose their effectiveness sometimes in as little as one week. Apply the dusts to cracks, crevices and wall and cabinet voids via puffing with a hand duster or using a mustard container as described in the article I wrote called, "Does Diatomaceous Earth Work As A Method Of Pest Control".

The key to control of German cockroaches is to use all the different management techniques; inspection, sanitation, exclusion and baits and dusts. Doing these techniques can effectively control these insects without a lot of expense hiring professionals to do the job for you.

American Cockroaches

In the southern U.S. American cockroaches are commonly found in the landscape around homes. They may live in tree holes, wood piles, around rain gutters, within the soffits of the roof-line, and in attics and crawlspaces.

They will readily move indoors at night to forage for food and water. Their indoor activity increases during periods of cold, excessive rainfall and in extremely hot and dry weather.

American cockroach control is a lot easier when the outdoor areas where they like to live are removed or modified to make them uninhabitable. Removing old wood piles or placing baits sprinkled among the wood will help control American cockroaches. During dry spells dusting Boric acid powder or Diatomaceous Earth helps but remember both become ineffective when they get wet.

Exclusion techniques become very important in keeping American cockroaches out of the home. This includes caulking or sealing any potential entry point.

If your home has brick siding with weep holes the best method of sealing the weep holes to prevent American cockroach entry is to insert small squares of metal window screen into the weep holes with a small putty knife. This allows the weep holes to function as designed but prevents cockroach entry through them.

Place bait formulations around and near areas that can become wet or moist. Remember to be careful using the Maple syrup Boric acid bait since it resembles peanut butter and pets and toddlers may find and eat it.

Puff dusts of Boric acid or Food Grade Diatomaceous Earth into cracks, crevices and voids that will remain dry.

Oriental Cockroaches

Oriental cockroaches like dark moist areas like those found under porches, in crawlspaces, basements and drains in floors. Outdoors and away from houses they can be found in abandoned cisterns, where water valves and meters are below ground level. Other places they like include underneath the bark mulch placed under shrubs near foundations, stone walls and where garbage and trash is found.

A very common route for Oriental cockroaches to enter houses are along plumbing, especially where plumbing enters the house from crawlspaces. Other common points of entry include coming in under door and window jambs. These places should be caulked or screened to deny Oriental cockroaches entrance.

Brownbanded Cockroaches

Brownbanded cockroaches are the type of cockroach that likes warmer, drier places than German cockroaches like. Brownbanded cockroaches are typically found dispersed throughout a home or other building. They are almost always found indoors, unless you live in a tropical area.

Brownbanded cockroaches can be very hard to eradicate because they tend to live singly or in small groups scattered all throughout a building. When these cockroaches are suspected an inspection must be very thorough and attention must be paid to upper areas in rooms such as above light fixtures.

One effective method of control of Brownbanded cockroaches is to dust inside of dressers, on any shelves in closets, in ceiling light fixtures and even behind valances on windows. Recommended dusts are Food Grade Diatomaceous Earth and Boric acid powder.

Smokybrown Cockroaches

Smokybrown cockroaches have habits similar to American cockroaches. But they typically move around more than American cockroaches and are usually discovered to be living both inside and outside of homes and other buildings. This means the treatment for them is of a larger magnitude than treating for American cockroaches.

These cockroaches can be found living in and around crawlspaces, garages, attics, flower beds, trees - especially in tree holes, shrubs, garbage and trash cans, woodpiles, railroad ties plus just about any other place they could hide.

Smokybrown cockroaches are more susceptible to desiccation than other cockroaches. A common place to find them breeding is in the insulation in the attic under a leaky portion of the roof. Correcting leaky roofs and plumbing often markedly reduces Smokybrown cockroach populations.

Dusting in attics and crawl spaces with Diatomaceous Earth or Boric acid powder can go a long way to help reduce Smokybrown cockroaches. Just remember that both of these dust treatments become ineffective when the dust or powder gets wet.

It is often necessary to caulk cracks in wood shingle roofs and on the outsides of building to deny entry through these places to Smokybrown cockroaches. Check to be sure these cockroaches are not living in debris trapped in rain gutters.

Caution: resist the temptation to fill tree holes with concrete or other filler material. Most of these materials will separate or pull away from the tree hole and end up creating great harborage spaces that actually increase the number of Smokybrown cockroaches instead of decreasing them! It is better to treat tree holes with baits instead of trying to eliminate them.

Asian Cockroaches

Asian cockroaches can present a very difficult challenge. Although basically an outdoor dwelling cockroach, they readily enter homes and can infest them. Adults are strong fliers and are attracted by lights outside of a home and inside a home. Another attraction for Asian cockroaches are light-colored surfaces and areas around a home.

One of the first chores needed to reduce the population of these cockroaches is to rake and remove any leaves or mulched areas around a home. These provide harborage for Asian cockroaches.

Next remove any food sources such as pet dishes and garbage cans that are kept near the home.

Following these changes, it is time to look at exclusion techniques such as caulking, weatherstripping and screening weep-holes in brick siding. Then turn attention to bright lights near doorways and outside the house and dim them if at all possible or use bug light bulbs in them.

If considering new construction or remodeling in areas where Asian cockroaches are, consider moving outside lights away from doorways and placing them where the door way is only in the beam of light. Not with a light that attracts these flying cockroaches to draw them to the doors of the house!

Don't forget to locate and treat outdoor breeding sites. In dry weather you can dust the breeding sites with Diatomaceous Earth or Boric acid. You can also use the boric acid bait formulas around the breeding site if that can be done so pets and toddlers do not have access to the baits.

Once these cockroaches get inside, look for and treat them as you would any cockroach type. Perhaps you might leave a ceiling light on in a room at night with baits placed near the ceiling light and dust placed inside the light fixture. Hoping to congregate these pests to that room and set up their demise.

Built-In Cockroach Pest Control

If you live in an area where cockroach infestation is a problem and are building or doing extensive remodeling, consider placing boric acid powder inside the wall voids and underneath ceiling insulation during construction.

The Boric acid powder will remain effective as long as it is dry and could continue killing cockroaches and other insects for years into the future. By being inside wall voids and underneath attic insulation the Boric acid powder is not readily accessible to pets and toddlers.

Related Questions

Why don't you recommend the use of Pest Control Diatomaceous Earth? Because it has additional chemicals to attract cockroaches and other insects and some of these chemicals can harm pets and toddlers whereas Food Grade Diatomaceous Earth does not have these potentially harmful chemicals yet kills insects just fine.

Wouldn't it be a good idea to increase the amount of Boric Acid in the bait formulas to achieve a quicker kill? Actually the answer is No! If the cockroaches die before they make it back to their nests or harborage areas there is less chance of other cockroaches cannibalizing them and ingesting Boric acid and dying. So you do not get the added effect of killing two or more cockroaches with only one eating of the bait.

What precautions should be followed when dusting with Diatomaceous Earth or Boric acid?

  • Avoid inhaling the dust of either product.
  • Only leave a thin layer of dust. The cockroaches will walk around piles of the dusts.
  • As soon as finished dusting with either type of dust wash any exposed skin the dust might have gotten on and change and wash the clothes you wore when using Boric acid to prevent there being a source of Boric acid pets or toddlers might come in contact with.

You can learn more about Diatomaceous Earth in an article I wrote called, "Diatomaceous Earth⎜Uses, Health Benefits, Is It Safe". For more information about Boric acid go to another article I wrote titled, "Can Boric Acid Kill Insects Safely And Inexpensively".

About The Author

John Brownlee

John is a retired Lawyer, Health Care Provider and has a certificate in Pest Management Technology. He teaches people how to locate, evaluate, and purchase Country and Homestead Property. He and his wife, Linda, share their knowledge of homesteading skills and safe pest management.