ENY-214

Cockroaches and Their Management1

P. G. Koehler, B. E. Bayer, and D. Branscome2

Cockroaches have various common names including water

bugs, croton bugs and palmetto bugs. There are at least
69 different cockroach species found in the United States.
Outside, cockroaches are decomposers, feeding on dead
or dying plants and animals. However, they are considered
pests when they interact with people, invading lawns and
gardens or entering homes and other structures. More
importantly, they can affect human health by spreading
diseases, such as Salmonella, and ruin materials such as
books, clothes and food.

Cockroaches secrete an oily liquid that has an offensive and

sickening odor. This odor may also be imparted to dishes
that are apparently clean, food and clothes. Excrement in
the form of pellets or an inklike liquid also contributes to
this nauseating odor. Additionally, cockroaches produce
allergens, which include their feces, shed skins, and body
parts such as antennae and legs. In susceptible individuals,
contact with these allergens can result in mild to severe
rashes, other allergic reactions, and in extreme cases death
from asthma attacks. This fact sheet is excerpted from SP486: Pests in and around the
Southern Home, which is available from the UF/IFAS Extension
Bookstore. http://ifasbooks.ifas.ufl.edu/p-1222-pests-in-and-around-
the-southern-home.aspx
Credit: UF/IFAS

1. This document is ENY-214, one of a series of the Entomology and Nematology Department, UF/IFAS Extension. Original publication date April 1994.
Revised January 2003, July 2011, and February 2022. Visit the EDIS website at https://edis.ifas.ufl.edu for the currently supported version of this
publication.

2. P. G. Koehler, professor emeritus; B. E. Bayer; and D. Branscome, graduate assistant; Entomology and Nematology Department, UF/IFAS Extension,
Gainesville, FL 32611.

The use of trade names in this publication is solely for the purpose of providing specific information. UF/IFAS does not guarantee or warranty the
products named, and references to them in this publication do not signify our approval to the exclusion of other products of suitable composition.

All chemicals should be used in accordance with directions on the manufacturer’s label.

Use pesticides safely. Read and follow directions on the manufacturer’s label.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services
only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status,
national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county’s UF/IFAS Extension office.
U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County
Commissioners Cooperating. Andra Johnson, dean for UF/IFAS Extension.
Cockroach Species
The cockroaches most commonly found in and around
Florida homes are the Florida woods roach (Figure 1),
American (Figure 2), smokybrown (Figure 3), brown
(Figure 4), Australian (Figure 5), German (Figure 6) and
Asian (Figure 7). The smallest cockroaches—the German,
Asian and brownbanded (Figure 8)—are close to the same
size, and the adults are seldom more than 5/8 inch long
(16mm). The larger cockroaches—American, Australian,
brown, and the smokybrown—are 1–1/4 to 2 inches (31–51
mm) long and are often called palmetto bugs. Though they
are generally found outdoors, they can become indoor
problems when they migrate or are carried indoors. The Figure 2. American cockroach egg case, adult and nymph. Adult actual
largest cockroach, the Florida woods roach, will also enter size 11/2” (38 mm).
dwellings from outside. Outdoor cockroaches do not
survive well indoors, and many times people overreact to
the presence of these cockroaches. Often, removal of these
outdoor cockroaches from the house is all that is needed for
control.

Figure 3. Smokybrown cockroach egg case, adult and nymph. Adult

actual size 13/4” (44.5 mm).

Figure 1. Florida woods cockroach and egg case. Adult actual size 11/4”
(31.75 mm).

The Asian cockroach looks very much like a German cock-

roach, except it flies. Asian cockroaches live outside and are
attracted to the lights from buildings. They will fly to porch
lights and find their way inside. Once inside, however, their
survival is poor, like other outdoor cockroaches.

Figure 4. Brown cockroach adult, actual size, 11/2” (38 mm).

Cockroaches and Their Management 2

 Figure 8. Brownbanded cockroach male, female, nymph, and egg case.
Adult actual size, 3/4” (19 mm).

Development of the Cockroach

Figure 5. Australian cockroach adult, actual size 11/2” (38mm).
Cockroaches have three life stages: egg, nymph and adult.
Cockroach eggs are deposited in groups in a leathery
case or capsule called an ootheca. This capsule is usually
dropped or glued to some surface by the female soon
after it is formed. However, the female German cockroach
carries the capsule protruding from her body until the eggs
are ready to hatch. There may be from 30 to 48 eggs in the
capsule of the German cockroach, but capsules of other
cockroaches may have only 10 to 28 eggs.

The newly hatched nymphs have no wings and shed their

skins (molt) several times before becoming winged adults.
German and brownbanded cockroaches may have several
generations per year, but the outdoor species may require a
Figure 6. German cockroach male, female, nymph, and egg case. Adult year to develop from egg to adult.
actual size 5/8” (16 mm).

Where to Look for Cockroaches

Cockroaches hide in dark, sheltered places during the day
and come out to feed at night. Inside, they may be found
around the kitchen sink or drain board, in cracks around
or underneath cupboards and cabinets or inside them
(especially in the upper corners), behind drawers, around
pipes or conduits (where they pass along the wall or go
through it), behind window or door frames, behind loose
baseboards or molding strips, on the underside of tables
and chairs, in the bathroom, and in radio and TV cabinets.

The German cockroach is usually found in the kitchen and

bathroom, although it may be found all over the house. The
other cockroaches prefer damp, warm locations and usually
develop in garages, sewers, attics, storerooms and similar
locations, and then enter the home from outside breeding
sites.
Figure 7. Asian cockroach male and female. Adult actual size 5/8” (16
mm).

Cockroaches and Their Management 3

Outside, cockroaches can be found in leaf litter, mulch, • Caulk or otherwise seal cracks and gaps around frames of
under vegetation, in tree holes, and in palm trees. doors and windows and around plumbing and electrical
to help prevent cockroaches from entering your home.
Methods of Cockroach Control • Seal gaps between door frames and doors with weather
An integrated pest management (IPM) approach is the stripping.
most effective method of cockroach control. Chemical use • Children can transport cockroaches from school to home
alone is the least effective control method. Using chemicals in book bags and lunch containers. Inspect these items
alone can result in insecticide resistance and, ultimately, regularly.
very poor control.
• Dwellings such as apartments that are separated by a
Homeowners may undertake their own IPM plan for common wall are particularly difficult situations. An
cockroach control with good success, or they may elect to infestation can migrate between apartments via the
contract the services of a professional pest control operator. plumbing within a common wall. Therefore, cockroaches
Professionals have the equipment and training to do a from one apartment can easily migrate to another apart-
thorough job and have access to products not available to ment, infesting a “clean” dwelling. To help prevent this,
homeowners. If you decide to contract the services of a caulk holes in common walls and around plumbing.
professional pest control operator, get estimates from some ELIMINATION OF WATER SOURCES
reputable firms before you decide on one. Water is the most important factor in cockroach survival.
German cockroaches can survive only 12 days with food
Prevention and Sanitation but no water. However, if only water is present with no
Successful cockroach control requires prevention and food, cockroaches can survive for about 42 days. Cock-
sanitation. Vacuuming will eliminate cockroach skins and roaches often come indoors during periods of drought
feces that cause cockroach allergies. Cockroach feces also because they are looking for moisture. Eliminate water
contain a chemical (aggregation pheromone) that attracts sources by doing the following:
cockroaches to an area. Eliminating the cockroach feces by
scrubbing with hot, soapy water will decrease the amount • Repair plumbing leaks by tightening connections or
of aggregation pheromone available to attract cockroaches patching leaky pipes, especially in kitchen and bathroom
to the area. areas.
• Do not let water stand in sinks for long periods of time.
Prevention and sanitation can be divided into four catego-
ries: exclusion; and elimination of water, food and harbor- • Do not overwater indoor plants because accumulated
age. Following the recommendations in the four categories water will be available to cockroaches.
will likely eliminate the most important factors that affect • Empty pans under refrigerators used to catch water from
cockroach establishment. condensation.
• Be aware that pet drinking dishes, aquaria and pipe
EXCLUSION condensation (under sinks, in wall voids) can also be
• German cockroaches can initially infest a structure when sources of moisture.
infested grocery bags are brought inside. Inspect grocer-
• Eliminate places outside where water can collect, such as
ies for cockroaches before storing. Keep grocery bags in
cans, tires and tree holes.
outside storage areas.
• Cockroaches breed prolifically in corrugated cardboard ELIMINATION OF FOOD SOURCES
boxes. Discard unnecessary boxes immediately. Cockroaches do not need large amounts of food to survive,
especially in the presence of water, but availability of food
• Keep doors and windows shut.
can cause populations to increase rapidly. Furthermore,
• Keep window and soffit screens in good repair to prevent food sources compete with cockroach baits, decreasing
cockroaches from entering your home. their effectiveness. Elimination of food sources includes:
• Check attic vents and make sure that large openings
around outside drainage lines and sewer vents are • Store and dispose of garbage properly. The highest
screened or sealed. Use tightly packed steel wool as a concentration of cockroaches in a home is usually around
temporary filler until openings can be sealed properly. the garbage can and around the refrigerator.

Cockroaches and Their Management 4

• Seal lids in garbage contaners to prevent cockroaches Chemical Control
from accessing food sources. Also, keep garbage areas Use prevention and sanitation methods before and concur-
clean by wiping frequently. rently with chemical control tactics. The most commonly
• Dump sink strainers frequently to prevent food buildup. used chemical formulations for cockroach control are baits,
• Wipe off counters tops often. sprays, and dusts. While cockroach foggers are commonly
seen in the marketplace, their effect is limited to the cock-
• Wash dishes immediately after use. Dishes left unwashed roaches that directly contact the fog. Thus, control from
are a major source of food for a kitchen infestation. foggers is variable and will not be discussed here.
• Keep kitchen appliances such as toasters, toaster ovens,
microwaves, stoves, ovens, and refrigerators free of BAITS
crumbs and other food debris. In addition, clean the areas Baits are most highly recommended because of their
around these appliances. effectiveness and targeted application, while decreasing
• Reseal all food after opening, place in a tightly sealed unnecessary pesticide exposure. Baits usually come in
container or store in the refrigerator. granular formulations, plastic stations, or large syringes for
gel applications.
• Seal pet food tightly. Do not leave food and water out all
the time. • Apply granular formulations outside in plants and
ELIMINATION OF HARBORAGES mulched areas.
In addition to food and moisture, cockroaches require • Bait stations are most effective when placed around
a place to live. The cockroach harborage is critical to its corners where you suspect cockroaches are hiding or
survival. Cockroaches prefer dark places that are warm coming into your home.
and moist. Places that provide tight spaces such as stacks • Get small stations for German cockroaches and large
of newspaper or cardboard, piles of clothing, or cracks and stations for the larger outdoor cockroaches.
crevices in structures are ideal harborages for cockroaches.
• Place the gel bait in cracks and crevices around windows,
Harborages not only provide a place for cockroaches to doors, and any other suspected cockroach harborage,
live, but they also can create “pesticide free” zones where except in food handling areas.
cockroaches can hide if insecticides are selected as one • Never spray a liquid insecticide where baits have been
tactic in the IPM program. Eliminate harborages by doing applied. Liquid insecticides used in the vicinity of baits
the following: will repel cockroaches from the bait.

• Seal cracks and crevices. Adult cockroaches can fit into • Pest control operators have other baits in different forms
cracks only about 1/16 inch and prefer spaces of about that also provide long-lasting control.
3/8 inch (9.5 mm). INSECT GROWTH REGULATOR
• Pull mulch away from the house. The large, outdoor • Insect growth regulators (IGR) require four to six weeks
cockroaches breed prolifically in pine straw mulch and for a noticeable decrease in the cockroach popula-
poorly in gravel or on bare soil. tion. But control is longer lasting than other contact
insecticides because the cockroaches are no longer able
• Stack firewood off the ground and well away from the
to reproduce once exposed. Evidence of IGR exposure
house.
are twisted wings on the adult cockroaches and altered
• Fill tree holes with cement to remove this prime harbor- behavior. Expect to see more cockroaches during the day
age area. as a result of IGR use. Seeing more cockroaches after IGR
• Keep shrubbery and ornamentals well trimmed and use means the treatment is working. Baits can be used in
away from the house. Ivy is a favorite breeding place for conjunction with IGRs.
outdoor cockroaches. SPRAYS
• Keep clutter such as newspapers, bags, and clothing from • Greasy surfaces decrease the effectiveness of insecticide
accumulating. applications. Therefore, before treating surfaces, eliminate
grease and oil by scrubbing with hot, soapy water.
• Generally, liquid sprays will not be effective when applied
to wood surfaces such as cabinets and shelves.

Cockroaches and Their Management 5

• Apply materials to cracks and crevices where cockroaches • If populations are very high, a “clean-out” may be needed
live. These areas include cracks around pipes under sinks, to knock down the initial population. Use a liquid
around toilet bowls, around baseboards, and around insecticide mixed with an insect growth regulator, such as
appliances. hydroprene or pyriproxyfen, in cracks and crevices.
• Never spray around or into electrical outlets. • Place baits in areas not treated with liquid insecticide or
• Sprays are effective for controlling exposed insects. place baits four to six weeks after spraying.

• Avoid spraying food preparation surfaces. An IPM Approach for Outdoor

• Do not touch surfaces until dry (at least 4 hours). Cockroaches
• An 80% or better reduction in cockroach abundance can
• Some materials may damage carpets, tile, or plastics.
be achieved using the following IPM approach.
Check the label before using any material on these
surfaces. • Use only a thin layer of mulch around the home that
extends 1 ft (30.5 cm) out from the foundation. This will
• Outdoor products should be applied at the label rate to
allow drying time and make conditions less conducive to
cracks and crevices where cockroaches are suspected of
cockroach survival.
living or entering the home, such as door thresholds and
window frames. Apply control products within 3 feet (91.5 cm) of the
home in pine straw, fallen leaves, or ivy, and next to other
• A perimeter treatment along the base of the foundation
cockroach habitats such as garden borders, large rocks, or
wall, in cracks and crevices, and at points of entry
railroad ties. Always follow the label.
into the home can also help control the larger outdoor
cockroaches. Sealing cracks and crevices is recommended
Treat sheltered cracks and crevices such as porch corners,
prior to the spray treatment.
under ledges, in crawl space gratings, and under garage
DUSTS doors. Baits or liquid products can be used, but not both at
Dusts are slow-acting but can give long-lasting control. the same time in the same place.
Boric acid is probably the most commonly used dust
labeled for cockroach control. It is most effective indoors in Precautions
clean, dry areas.
All insecticides are poisons. Read the entire label, including
the small print before opening the containers and heed all
• Apply boric acid with a duster that puts out a thin film of
warnings and cautions. Store pesticides in their original
dust.
labeled containers out of reach of children, irresponsible
• Apply dusts in hidden areas such as under refrigerators, people, and pets, and preferably keep under lock and key.
stoves, sinks, wall voids, and other cracks and crevices. Dispose of leftover spray materials and empty containers
• Do not apply dusts in open areas such as on shelves or promptly and safely.
counters where food and utensils are kept.
• Boric acid is highly toxic to plants and will discolor some
fabrics.
• Other effective dust and borate products are available to
pest control operators.
IPM Approach for Indoor Cockroaches
• Thoroughly vacuum and wipe the premises with hot
soapy water.
• Place baits (gel and station type) according to label
directions.
• Check baits monthly until populations decrease, then
quarterly.
• Replace empty bait stations because they provide ad-
ditional harborage for cockroaches when empty.

Cockroaches and Their Management 6