Cockroach Control Manual

(J. Kalisch)

Figure 5-1. “I admit I seen a few waterbugs, but I got no cockroach problems.”

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 Primary Control Strategies: Modify Resources

Chapter 5
Primary Control Strategies:
Modify Resources
Rhonda, The Roach
Cockroach infestations do not appear out of
thin air, even though it may seem that way. German
and brownbanded cockroaches are nearly always
imported into the structure by human activities.
What happens when a cockroach is introduced into
a new building? By way of illustrating our discussion,

(A. Sheffield)
let us look at this situation from a cockroach’s
viewpoint. We will call our roach Rhonda.
Rhonda, a female German cockroach bearing a
fertile egg case, has been living for the past two weeks Figure 5-2. Rhonda the roach, visibly stressed, is
in the produce section of a supermarket. After a night looking for a place to hide.
of foraging, she crawled into a five-pound bag of
potatoes. Her bag of potatoes was carefully selected this bathroom, basement or commercial kitchen
morning by Mrs. Porter who bought the potatoes to has a capacity to support a certain number of
make German potato salad for the Ladies Aid Society cockroaches. This is called the carrying capacity for
pot-luck luncheon on Saturday. After a bumpy ride the specific cockroach species living there (Figure
in the back of the car, Mrs. Porter carried the sack of 5-3). Biological forces always aim to maintain the
potatoes into the house and set it on the pantry floor. population at this level, regardless of measures taken
Rhonda isn’t comfortable in the sack of potatoes, so to reduce the population, like pesticide applications.
when the activity quiets down, she starts looking for After an insecticide application, the remaining
a hiding place. Because Mrs. Porter has a neat pantry
area, Rhonda cannot find a very good hiding place.
She finally settles behind a box of laundry detergent.
Tonight she must search out a more permanent place
to live. If she finds a better place, she will mark the
newly-found shelter with an aggregation pheromone
before she leaves to look for food or water. Marking
this place will help her find it again.
(C. Ogg)

If Rhonda cannot find a suitable shelter, she will

travel from place to place finding temporary places to
hide. She will be stressed and have to deposit her egg Figure 5-3. The carrying capacity of the
case in an unsuitable place. Few of her 30+ offspring environment is based on resources provided by
will survive and an infestation cannot get started. If the environment and required by the animal.
Rhonda cannot find a food and water source, she will Every kitchen has the capacity to harbor a
also die after a week or two. cockroach population.
The lesson in the story is this: every habitat,
whether it is a house or apartment kitchen,

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 Cockroach Control Manual

roaches will have less competition for food and time (Figure 5-4). Cockroaches can squeeze into
hiding places (resources). Their reproductive rate cracks 1/16 of an inch or larger. Cockroaches like
will increase and, in no time, the roach population warmth produced by electric motors, condensers
will rebound. and ovens and may live inside appliances, especially
The key to effective control is to lower if there is water nearby.
the carrying capacity of the environment by
eliminating the resources needed by cockroaches.
These needed resources are water, food and
shelter.
Like any animal, cockroaches need these

(J. Kalisch)
resources to thrive and reproduce. Only small
amounts of water and food may be required. The
resources in every habitat determine whether or not
an infestation can be established and the potential Figure 5-4. Cockroaches live most comfortably in
infestation level. Let’s discuss each of these required tight places.
resources individually.

Essential Resources: Reduce Water Availability

For German and oriental cockroaches, limiting
Water, Food and Shelter the availability of water will quickly stress them and
make control efforts more effective. It is the first
Water. Cockroaches have a waxy coating step you should take in your control program.
on their body to prevent moisture loss, but they Plumbing Problems. Examine all the sinks in
still need water. One drop of water per day is all your home. Do your faucets leak? If so, you need to
a cockroach needs. Any water or moisture will repair them. Inspect the base of the faucet and run
do; they can get water from condensation on the water. Does the base of the faucet leak? Replace
pipes, small leaks, moist sponges, soaked wood the gasket. Then, examine the faucet opening and
and moistened food. Different cockroaches have see if there is a screen present, if not, install one.
different water requirements. Of those roach This screen breaks up the flow of water into a
species we are discussing, the German and oriental steady stream. But, it also helps to prevent thirsty
cockroaches need moisture most frequently. cockroaches from getting into the faucet to get
Food. Cockroaches eat almost anything: water.
crumbs, hair, fingernail clippings, spots of grease, Make sure there are no leaks in the plumbing
soiled clothes, pet fur and dead insects (even dead underneath the sink especially when the water is
cockroaches). Very small, immature cockroaches off. Repair any leaks, no matter how small. Carefully
stay in hiding places and eat droppings of older look for a whitish residue at all connections. This
cockroaches. If food becomes scarce, cockroaches whitish residue is a sign of slow water leakage.
will cannibalize their own young and eat egg cases. Clean the residue, tighten the connection, and
Studies have shown cockroaches eat a balanced diet check it daily for a week or two to make sure the
whenever they can. Food high in protein or is moist, leak is sealed.
is very attractive to cockroaches. If you are leaving Cold water pipes may sweat from condensation,
pet food in the dish overnight, you are feeding your especially during humid weather in the summer.
cockroaches. And, feeding them well. There is enough moisture on sweating pipes to
Shelter. Cockroaches live in cracks and crevices sustain cockroaches. Pipe insulation will help solve
during the day. They prefer wood and paper in their this problem. Make sure you use non-absorbent
living quarters rather than metal surfaces. Their flat insulation because if it absorbs water, it may
body allows them to squeeze into places where they grow mold and attract cockroaches. Be sure to
can touch the surfaces above and below at the same seal the insulation thoroughly. Be careful not to

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 Primary Control Strategies: Modify Resources

create hiding places for cockroaches between the

insulation materials and the pipes.
All drains should be covered with a fine mesh
screen. Cockroaches do not normally enter a
structure through a drain but will readily enter
drains in search of water. Most kitchen sink strainers
will not keep cockroaches from going down the
drain. Use a strainer with small round holes, instead

(V. Jedlicka)
of slits. Bathroom sink and tub overflow holes must
also be kept clean and washed out occasionally.
Other water sources. Before storing moist
sponges or dish rags overnight, rinse them with an Figure 5-5. The drip pan of a frost-free
ammonia water solution. This prevents cockroaches refrigerator is attractive to German cockroaches.
from using this source of moisture. You may want There is warmth from the compressor and plenty
to seal sponges in a sandwich bag overnight. of food and moisture nearby.
Check plant pot dishes, and make sure there is
no standing water in the dishes. Also, place a layer
of gravel over the soil in plant pots to cover exposed containers before being stored in the home. No open
moist soil. food should be left out overnight. Candy, popcorn,
Petroleum jelly and mineral oil mixed together fruit and pet foods must be placed in containers
and applied to the inside rim of the bowl and around for overnight storage. It is hard to completely
the tank of all toilet bowls will prevent cockroaches deprive cockroaches of food, but limiting food
from using them as a source of water. This mixture makes it easier for other control methods to work
should be reapplied weekly. effectively.
Always clean and dry dishes, pots and pans Food Waste Management. While food
immediately after each use. Never leave dishes in products are an important source for cockroaches,
the sink with water in them. food waste (garbage) is readily consumed by
Remove pet water dishes overnight and replace cockroaches. A garbage disposal is very helpful in
each morning. reducing waste in the home. However, the garbage
If your dwelling has excessive humidity, consider disposal must be used daily or whenever waste is
purchasing and using a dehumidifier to reduce the
humidity. Empty the tank frequently to prevent its
use as a water source by cockroaches.
At least once a month, check the drip pan under
the refrigerator (Figure 5-5). Clean and dry the pan
before replacing it.

Remove Their Food Supply

Stored Food. Cockroaches eat just about
anything. All food items must be kept in a sealed
container. Once a package of food is opened, make
sure it is tightly resealed. If the original package
(S. Cochran)

doesn’t reseal tightly enough, place the food

product in a tightly-sealed container. Cockroaches
can easily chew through paper, cardboard or thin
plastic containers, so food items packaged in these Figure 5-6. If you are leaving pet food out
materials should be transferred to cockroach-proof overnight, you are feeding your cockroaches, too.

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 Cockroach Control Manual

deposited, and it should be flushed with a cleaning Before you begin any control efforts, pull out
solution after each use. refrigerators, stoves, freezers and clean behind and
If a garbage disposal is not available, remove beside them. Wash the outside of the appliance.
garbage to an outdoor, sealed container before Remove the back of appliances and vacuum dusty
evening. If this is not possible, waste food can be areas around motors. (Be sure to unplug appliances
placed in cockroach-proof containers like glass jars when doing this.) Remove items from cupboards,
with air-tight lids. vacuum and clean thoroughly (Figure 5-7). Wash
Clean all surfaces in food preparation or floors. Clean under burners and the stove top. Be
eating areas, including counters, tables and floors sure not to forget the inside and outside the oven
with a cleaning solution after each use. Dishes, and the broiler area, if you have a gas stove. It is
bowls, utensils and glasses should be immediately important to remove grease. (Cockroaches eat
cleaned. grease with gusto!)
Grease is a special problem and can be hard to
clean. Cockroaches feed on the film of grease on
oven hoods and walls next to where frying pans
Cockroaches and Rodents
have been used. Cockroaches and mice often coexist in the same
Clean all spills. Spilled food residue will attract dwelling. Both cockroaches and mice are nocturnal
cockroaches. Sponges, cleaning pads and brushes and live in dark, hidden locations. Cockroaches eat
must be thoroughly cleaned after use. Soiled mouse feces and mice, in turn, may eat cockroaches.
clothing should be placed in an area not readily Cockroaches eat mouse baits (pellets, blocks)
accessible to cockroaches, such as a sealed plastic without adverse results. If you are using bait to
bag or a tight fitting hamper (without ventilation control mice, you may be feeding cockroaches.
holes).
Initial Cleaning Efforts. Most of us tend to
put off deep cleaning jobs (like ovens, behind stoves
Eliminate Hiding Places
and refrigerators) until we have a good reason to Remove Clutter. Remember, cockroaches
do them. If you have cockroaches, there should be prefer to be in tight, small places. These areas are
an incentive to make this extra effort. In fact, there where they feel secure, rest, mate and breed. Most
is a good possibility those difficult cleaning areas cockroaches only need a 1/16” space, so even small
are contributing to your cockroach infestation. cracks and crevices provide ample harborage. Also,
When you clean, you may see cockroaches. Have cockroaches prefer porous surfaces like wood,
the vacuum cleaner handy and vac ’em up. paper, cardboard, insulation, and cloth. Stainless
steel, aluminum, plastic laminates, ceramic tiles
or baked enamel surfaces are less preferred. If you
change the habitat, try to use materials cockroaches
dislike. When soft, porous materials are layered
(such as corrugated cardboard), it forms a
cockroach breeding area. Do not keep stacks of
paper bags, sacks, cardboard boxes, rags or pieces
of wood in locations where cockroaches may be
present. One of the biggest mistakes is the practice
of storing paper bags between an appliance and the
wall because it establishes a layering effect next to a
warm area. This paper bag storage practice is an
(V. Jedlicka)

excellent cockroach breeding site.

Examine all areas, in the kitchen, bathrooms,
Figure 5-7 Clean thoroughly to remove food laundries, basement and storage closets, especially
particles, cockroaches and cockroach specs. near where cockroaches were found in your traps.

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 Primary Control Strategies: Modify Resources

caulks. For spaces greater than ½”, consider using

foam fillers and caulk over the foam. If caulking
all the cracks or seams in your home seems to be a
major undertaking, use monitoring sticky traps to
determine locations where cockroach infestations
are established and focus caulking and sealing
efforts in those areas.
If cockroaches are infesting the cracks or
seams, apply a cleaning solution and desiccation
dust (discussed in Chapter 6) to these areas before
caulking. Insecticide dusts can be used in void
areas, but make sure you read the section about

(B. Ogg)
application of dusts before you do this. After you
completely seal this area, cockroaches can no longer
Figure 5-8. A German cockroach and fecal specks use it as a hiding place.
near a stack of papers in a heavily infested, very Even high-grade silicone seals need to be
cluttered apartment. checked and cleaned regularly. If the edge of the
seal begins to flake or peel, clean out the caulk with
Re-organize and eliminate any clutter. Any portable a knife, and remove the entire section of caulk.
items providing harborage should be sealed in Then, clean and smooth the section with abrasive
cockroach-proof containers or heavy plastic bags. material, like sandpaper, and reapply the caulk.
Seal Them Out! After you eliminate clutter,
search the entire room, and find all cracks, seams
and crevices larger than 1/16”. Do not overlook
Don’t Overlook These Places
cabinets and furniture. These areas need to be There are some important areas in a kitchen
sealed so the cockroaches have no places to hides. which are often overlooked as a source of water,
Commonly neglected areas are behind molding, food or shelter. Ignoring these “secret” places can
small holes in cabinet doors, around rubber gaskets, counteract the effectiveness of other management
around water pipes, in hollow tube legs of kitchen tactics.
tables, where cabinets or walls meet each other, or
around built-in appliances.
Caulking is an easy, economical way to seal
most of these cockroach hiding places. There are
three types of caulk:
1. Latex caulk is usually cheap, but latex
eventually will crack and shrink.
2. Acrylic caulks are better than latex, but they
still shrink over time. In addition, cockroaches may
chew into latex or acrylic caulks.
3. Silicone caulks are the best! They are more
flexible, waterproof and can’t be chewed through.
Before you caulk those crevices, make sure the
edges of the space being sealed are clean and dry.
(C. Ogg)

Smooth the caulk so it forms a tight seal. Also, use

enough caulk to fill the width of the space and about
1/4-inch deep. You will need to use enough caulk Figure 5-9. Use caulk to seal cracks and crevices
so it will last. The disadvantage of silicone caulk is and void areas to eliminate these cockroach
paint will not adhere to the surface like the other hiding places.

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 Cockroach Control Manual

Refrigerators: Electrical Locations:

• Door gaskets should be checked and replaced if • Examine and caulk around electrical fixtures,
hard, stiff or cracked. (Yes, roaches can live under outlets and switches. For your safety, turn off the
refrigerator gaskets.) electricity.
• Vacuum the coil and compressor; wash and dry • Use a foam sealant if an infestation exists inside
the bottom drip tray. the electrical conduit.
• Check insulation around motors and clean or Metal Cabinets: Even though cockroaches
replace as needed. do not prefer metal, they will live in metal cabinets,
Dishwashers: if they have no other options. Metal cabinets are
• Check and repair all leaks. usually constructed with small openings which
• Remove bottom panel and clean regularly. allow cockroaches to get inside the doors. Examine

(C. Ogg)
• Check insulation for cleanliness and replace if cabinets carefully. Seal hinges, latches, seams and
needed. holes in the bottom and/or top of the doors.
• Check door gaskets and seals; replace them if Drawers: Pull out each kitchen drawer and
they leak. examine the cavity. When the drawer is closed, small
• Make sure food residue is removed from inside void areas are created which provide cockroach
the dishwasher daily. harborage (Figure 5-10)
Stoves: Small Appliances: Cockroaches can enter
• Clean the stove regularly and thoroughly. Don’t small appliances through small holes and cracks.
forget to clean under the burners. The most likely infested appliances is the microwave
• Use heatproof sealants to caulk cracks. oven, since is may not be cleaned regularly after
• Check insulation for possible infestations. You use and food particles may build up. It should not
may need to replace it. (Cockroaches can live be necessary to throw appliances away. Instead,
and breed in the insulation if they can gain access take the appliance apart or use a cold treatment,
inside the walls of the stove). discussed in Chapter 6.

(C. Ogg)

Figure 5-10. A kitchen drawer has been removed to expose a cluster of cockroaches
hiding in the void area created when the drawer is closed. Vacuum these cockroaches.

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