There is no difference between a cockroach and palmetto bug. The term palmetto bug is often used when referring to various species of cockroaches, especially in the Southeast region of the United States. In some areas, the American cockroach is often called a palmetto bug.
The American cockroach is likely to be called a palmetto bug when spotted in the Southeast. This is a common species of insect that typically lives outdoors in woodpiles, areas with mulch and sewers. American cockroaches are known to invade commercial buildings, but prefer damp conditions. Homeowners may encounter palmetto bugs while sitting outdoors. Adult palmetto bugs have large wings and are attracted to light near doorways, especially at night. The bugs are distinguished from other roach species by their reddish-brown bodies with light markings.
Two other types of cockroaches that may be called palmetto bugs are the German cockroach and smokeybrown cockroach. German cockroaches are common indoor pests found in homes and commercial buildings. They are identified by their dark bodies with light stripe markings. German cockroaches have wings, but typically don't fly. Unlike the German roach, the smokeybrown cockroach prefers humid outdoor settings. Homeowners might encounter them living in the eaves near an attic. Smokeybrown roaches have black bodies with long wings.