Palmetto bug, water bug and cockroach are all common names for the same creature. While numerous species of cockroaches live in the U.S., the American cockroach (Periplaneta americana) is the one most commonly referred to as a palmetto bug. Other large roach species are sometimes referred to as palmetto bugs, as well, including Australian (Periplaneta australasiae), brown (Periplaneta brunnea) and smokybrown (Periplaneta fuliginosa) cockroaches.

Periplaneta Americana On Pink Flower
credit: Bas Petter/iStock/Getty Images
American cockroaches, known as palmetto bugs, prefer outdoor living.

General Descriptions

American, Australian, smokybrown and brown cockroaches all range between 1 1/2 to 1 3/4 inches as adults. Except for the smokybrown, all have a dark body, yellowish thorax region and dark brown to black spots or markings on the yellow. Smokybrown cockroaches turn a rich mahogany color as adults.

Habitat Preferences

These larger roaches typically make their homes outdoors, but may appear inside if they migrate or are accidentally carried in. In the garden and yard, you can find palmetto bugs in dark, moist areas. They make their homes in piles of leaves, under mulch, in dead trees and holes, and under other types of vegetation.

Life Cycle

Palmetto bugs go through a three-stage life cycle: egg, nymph and adult. Nymphs look very similar to adults, although they are much smaller, lack wings and have slightly different markings. Adult females deposit their eggs in a case known as an ootheca that they carry around until the eggs hatch. Larger outdoor roaches of the types called palmetto bugs may take up to a full year to develop into adults.

Prevention and Control

Palmetto bugs outdoors may startle you, but they are ultimately harmless additions to your local ecosystem. When they get indoors, however, things can change quickly. Although the species called palmetto bugs don't always live well inside homes, they can still flourish and reproduce. Cleaning and sanitation is the best method to make your home inhospitable to these large roaches.

Vacuum frequently if you notice palmetto bugs indoors; shed skins and fecal matter will attract other roaches into your home. Repair any moisture problems such as leaks or standing water; roaches require a lot of moisture to live comfortably. Crumb-filled appliances, dirty dishes, garbage cans, sink traps and sink strainers hold valuable nutrition for palmetto bugs, so thoroughly clean, empty and seal these food sources.