Disease Carrying Pests: Cockroaches


Cockroaches are pests throughout the United States. They are annoying and, when abundant, they are also destructive. Cockroaches (also known as waterbugs, croton bugs or palmetto bugs) destroy food and damage fabrics, book bindings and other materials. When cockroaches run over food they leave filth and may spread disease. They secrete an oily liquid that has an offensive and sickening odor that may ruin food. This odor may also be imparted to dishes that are apparently clean. Excrement in the form of pellets or an ink-like liquid also contributes to this nauseating odor. Some people are allergic to cockroaches and become ill.

Kinds of Cockroaches

The species of cockroaches most commonly found in and around homes are American, Australian, brown, brownbanded, field, Florida woods, German, smokybrown and woods. The smallest cockroaches, the German and the brownbanded, are close to the same size and the adults are seldom more than 5/8 inch long. These two species are commonly found indoors. The largest cockroaches, the American, Australian, brown, and the smoky brown, are 1 1/4 to 2 inches long and are often called palmetto bugs.

Three other species, the Surinam, oriental and Cuban, range in size from 3/4 to 1 inch. These larger species are generally found outdoors, they can become an indoor problem when they migrate or are carried indoors. The largest native cockroach, the Florida woods cockroach, will also enter dwellings from the outside or from beneath the house. 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.

The Asian cockroach, a new invasive species in Florida, greatly resembles the German cockroach. Due to the differences in habitat, correct identification of the species is necessary, as it is with most cockroaches, to properly determine correct control measures.


The cockroach has three life stages: the 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 as soon as 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 they 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 year to develop from egg to adult.

Where to look

Cockroaches hide in dark, sheltered places during the day and come out to feed at night. 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 windows 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 kinds of cockroaches prefer damp, warm places and usually develop in garages, sewers, attics, storerooms and similar locations. They then enter the home from outside breeding sites.

Preventative Control

Inspect all baskets, bags or boxes of food, firewood and laundry brought into the house. Destroy any cockroaches or egg capsules. Make it difficult for cockroaches to enter by filling all openings around pipes passing through floors or walls with patching plaster putty, or plastic wood, particularly if cockroaches are coming in from adjoining apartments or from outside. Keep door and window screens in good repair and make sure that there are no cracks between them and the frames. Kill or remove any outdoor species of cockroaches found indoors. Often it is not necessary to spray insecticide to obtain control since outdoor cockroaches don't reproduce rapidly or survive well indoors.

Cleaning will aid considerably in cockroach control. Take away their food supply. Store food in tight containers and avoid spilling flour, cereals and other dry materials in cupboards or on pantry shelves. Do not leave remnants of food on tables or in kitchen sinks overnight. Sweep up any crumbs or bits of food from the floors of kitchen, pantry, and dining area. Put table scraps, vegetable parings and other waste materials in tightly covered garbage cans.