Cockroaches
Cockroaches, also known as waterbugs and
palmettobugs, are among the most difficult household
pests to control. Except for periods of warm weather when
they may migrate from house to house, domestic
cockroaches in Michigan spend their entire life inside
buildings. Usually they are found in basements, bathrooms
and kitchens where they feed upon a wide variety of
foods, including cereals, sugar-containing foods, meats,
cheese, beer and soda pop, as well as leather,
bookbindings, and wallpaper paste. They can be carried
into homes in cardboard cartons, sacks, beverage
containers, furniture and pet foods.
Cockroaches have long been companions of man. The old
Romans called them "lucifuga" because of their habit of
running away from light. Most cockroach species are
active at night and hide in dark areas during the day.
The word cockroach no doubt can be traced to the Spanish
word "cucaracha."
Cockroaches are one of the most disagreeable insects
that may invade homes. While it is not true that an
unkept home will cause a roach infestation, there is
indeed a strong correlation between sanitation and
cockroach populations once an infestation gets started.
The presence of roaches often causes serious mental
anguish for some homeowners. Roaches often associate
themselves with filth and are known to be involved in the
spread of bacterial organisms which cause gastroenteritis
and other intestinal infections. Some people are allergic
to cockroach secretions and cuticular proteins. Cockroach
body fluids contain an allergen which causes an allergic
reaction when there is contact with live roaches, roach
"byproducts" (fecal material and body parts) or
contaminated food and utensils. There is also a foul
smelling, oily liquid that is produced by most roach
species; this oily liquid is known to stain fabrics,
woodwork and other surfaces.
The exact origin of our domestic species is disputed,
but many are tropical forms and now are widely
distributed throughout the world by commerce. In our
area, we are commonly bothered by five different species
of cockroaches. Four of these are domestic roaches, while
the fifth is more at home outdoors but also gets into the
house.
The American cockroach, our largest, may grow to 1
1/2 inches (35 mm). It is reddish-brown or mahogany with
light markings on top of the thorax (the body division
that bears the winds and legs) and matures in about seven
months. The adults may live for up to 18 months. The
nymph are grayish-brown, becoming reddish-brown as they
mature, and wingless. It prefers damp areas such as
basements, and may be found around pipes, sewage systems,
and drainage systems in homes, commercial buildings and
greenhouses.
The Oriental cockroach is Black, 1 1/4 inches (30 mm)
long when full-grown and has short wings, the wings of
the female being only rudimentary. It may take as long as
22 months to mature, and is a relatively sluggish insect.
Living on filth, it travels along sewage systems into
homes. This species will migrate outside from building to
building and enter buildings through ventilators, broken
foundations, and under poorly fitted doors. It prefers
damp, cool areas, especially basements and crawl spaces
and near drains and leaky water pipes. They can be found
under sinks, refrigerators and washing machines if those
areas are damp. Outdoors they can be found beneath
decaying leaves and stones, and in mulch, garbage piles
and water-meter vaults.
The German cockroach is smaller, slightly over 1/2
inch (12-15 mm) long, brownish-tan with two black
parallel lines just behind the head. The nymphs are
darker, wingless, and also have two lengthwise stripes
behind the head. This species prefers high relative
humidity and warmth and is a significant pest problem in
homes, restaurants, hotels, food plants, warehouses,
dumps, office buildings, hospitals, ship and retail
stores. It is quite active and can easily migrate
throughout buildings thus becoming a major pest in
apartment buildings. This roach prefers a kitchen or
bathroom where there is plenty of food, moisture and
hiding places, but they can often be found in other parts
of the house as well. This species produces more eggs and
has more generations per year (3 or 4) than other
cockroaches; thus, a troublesome infestation can develop
rapidly after the chance introduction of just a few
individuals.
The brown-banded cockroach is a fairly recent
introduction first found in Florida in 1903. It has since
spread through the South and into some areas of the
northern U.S., being fairly common in Michigan. While it
normally congregates, individuals can wander throughout
the house, hiding in furniture, bookcases, television
sets, radios, computers, light switches, behind pictures
hung on the wall, and closets or other secluded
locations, especially those high off the floor. It is
slightly under 1/2 inch (10-12 mm) when mature, and is
colored a straw brown. Two brownish bands are located on
the wings of the adult, one where the wings join the
body, and one a little further back toward the wing tips.
The term "brown-banded", however, describes the immature
form more accurately than the adult, since the bands are
conspicuous on the abdomens of the nymphs. The species
prefers temperatures over 80 degrees F, and takes up to
150 days to mature at this temperature.
Another roach sometimes found invading the home in
the spring is the Pennsylvania wood roach. This species
lives outdoors and is not as fast nor wary as its house-
dwelling relatives. They may wander into buildings in
wooded areas, or may be brought into the house under the
bark of fireplace wood (they are common in woodpiles),
and can exist in the house living on food in the kitchen.
The males of this species have long wings and may fly for
short distances; indeed, they are often attracted to
porch lights and lighted windows. The females have short
wings and are usually found around houses only in wooded
situations. The adults are about 3/4 to 1 inch (20 - 25
mm) long and are colored a drab brown. They require one
year to mature.
Other roach species, such as the Australian roach,
Smokey-brown roach, Brown roach and Asian roach, may also
be found in Michigan from time to time.
Roaches lay their eggs in large numbers within a
single capsule (ootheca) which contains from 12 to 32
eggs, depending on the species. The egg compartments
within the capsule are indicated by grooves on the
outside. The egg capsules range in color from dark brown
to tannish brown and are somewhat bean-shaped They are
usually deposited in out-of-the-way places such as on the
underside of shelves, inside cupboard corners, bottoms of
drawers, and similar hard-to-see areas. Egg capsules from
which the eggs have hatched will float, while those that
have unhatched eggs will usually sink in water. The
nymphs grow slowly, requiring 2 to 18 months to complete
their development.
Integrated Cockroach Management
It is easier (and less costly) to prevent cockroaches
from entering a structure than it is to get rid of them.
They can be discouraged from invading buildings by
sealing cracks and crevices in foundations and outside
walls. Check the seal around vents, air conditioners,
windows, doors, utility entrances, and other openings
into the home.
Carefully inspect all incoming beverage cartons,
groceries, cardboard boxes, laundry, luggage, used/rented
furniture and appliances and firewood for the presence of
roaches or their egg cases.
Indoors, all potential hiding and breeding areas
should be eliminated. Cracks, crevices and holes in
floors, walls and ceilings should be repaired and
openings around plumbing fixtures, furnace flues,
electrical outlets, heating ducts, between window sills
and walls, and along baseboards and ceiling moldings
should be sealed.
Cleanliness in the home greatly lessens the
possibility of cockroach infestation. Unwashed dishes and
kitchen utensils and exposed food should not be left out
overnight. All spilled liquids should be cleaned up.
Cupboards, pantry shelves, storage bins, appliance motor
housings and floors where food particles accumulate
should be cleaned often, first by vacuuming and then with
soapy water. Kitchen wastes and dry pet food should be
kept in containers with tightly fitting lids.
All leaky pipes, backed up drains, condensation
problems and other sources of moisture must be repaired
or eliminated.
Control
Only after these preventative methods have been
employed should you begin your efforts to control the
pests with insecticides or traps. The first sign of
infestation may be scattered roach body fragments on the
floor or individual roaches caught in spider webs. Enter
dark rooms with a flashlight to locate infested areas.
Because various combinations of cockroaches can occur in
the same building, it is essential to accurately identify
the species present. This will permit the use of control
measures that take advantage of behavioral patterns and
life requirements of each particular species.
Non-chemical Controls
Non Baited Traps can be an effective way to reduce
cockroach populations (especially against brown-banded
and German cockroaches), and whenever possible should be
used in combination with preventative measures and
insecticidal treatments. Most cockroach traps are
rectangular or triangular cardboard "boxes" open at both
ends with the inside surface banded with a very sticky
adhesive and food attractant. Roaches enter the trap and
are immobilized in the adhesive. Traps should be
positioned (with both ends unobstructed) so as to
intercept roaches as they travel from their hiding places
to food sources. If no cockroaches are caught in a trap
after two nights, change its location. A properly placed
trap can catch numerous adults and/or nymphs on a daily
basis (as long as they are replaced when full). Traps are
also important for monitoring cockroach activity; for
example, assisting in species identification, identifying
infested areas, determining relative population density,
determining population composition (adults vs nymphs) and
monitoring effectiveness of chemical controls. Traps are
inexpensive, easy to use, disposable and contain no toxic
substances.
Ultrasonic Devices.
A variety of ultrasonic pest control devices have been
introduced on the market in recent years. Research on the
effectiveness of these devices has shown a number of
these products to have no effect on cockroaches. The
Environmental Protection Agency has taken action to
remove these devices from the market.
Biological Control.
Recently, a species of tiny parasitic wasp, Comperia
merceti (Compere) has been used to provide control of
brown-banded cockroaches. Other species of parasitic
wasps are known to parasitize cockroaches, and some of
these species may be the biocontrol agents of the future.
Baits or Baited Traps, or Insecticidal baits are
available in ready-to-use containers. They may be used to
supplement a control program. They are a very worthwhile
monitoring device. Use the baited traps before and after
initiating a control program to monitor populations.
Baits containing hydoprene, hydramethylnon and propoxur
are suggested.
Residual Insecticides.
Residual insecticides leave deposits on treated surfaces
which kill cockroaches for variable periods of time after
the application. The type of insecticide chosen and the
application method used will depend upon the location and
nature of the infestation. No one insecticide is best,
but various combinations can be effective. Regardless of
the insecticide chosen, a chemical applied to the areas
where cockroaches rest, hide, feed or walk will kill more
individuals than a chemical applied to areas which
cockroaches seldom frequent. Apply residuals to surfaces
less likely to be cleaned. One treatment rarely results
in complete control; retreatments are usually necessary.
Frequency of treatment will depend upon preventative
practices, thoroughness of insecticide application and
how vulnerable the structure is to reinfestation. You
will notice roaches around the home even after spraying
because it takes a while for the spray to kill them. They
should begin to disappear in a few days. If you still see
roaches a week after initial treatment, a thorough
retreatment is probably in order. Research has shown that
many residual insecticides cause repellency. When using a
repellent product, it is critical to do a complete
treatment if control is to be obtained. If any areas are
left untreated, cockroaches will be repelled from
treated hiding places into untreated ones. Also,
avoidance of an insecticide treated surfaces can be
learned by cockroaches exposed to sublethal doses.
Residual insecticides registered for cockroach control
are chlorpyrifos and propoxur. Important limitations of
these materials include=
(1) Do not treat entire walls or floors, only small areas
of baseboards, cabinets and other places where
cockroaches occur;
(2) Do not contaminate water, food, dishes or utensils
with them; and
(3) Dry all treated surfaces before allowing children or
pets on or near them.
Non-residual insecticides.
In addition to applying a residual spray to surfaces, a
pyrethrin or resmethrin spray can be used. A "total
release" aerosol spray is used to flush roaches out of
hiding places after the residual spray has been applied.
This helps assure that the cockroaches will contact the
active residual insecticide. The use of non-residual
insecticides alone, however, seldom gives effective
control.
A dust formulation is also suggested to control
cockroaches Boric Acid. Boric acid applied to cockroach
runways is ingested by roaches as they clean themselves,
eventually acting as a stomach poison.
Professional Control
If a severe, widespread or persistent cockroach
infestation occurs, or if you are in doubt as to proper
control measures, employ a reputable pest control
operator. These professionals have the knowledge,
training and equipment to do a thorough job.
For a complete listing of suggested control options for
all home, yard and garden insect pests contact your local
Extension Service, found under local government in the
phone book.