American Cockroach
Periplaneta americana
American Cockroach
Photo courtesy of: Landcare Research www.landcareresearch.co.nz 
This species is established in New Zealand.
Description
The American cockroach Periplaneta americana grows to a length of 2.5 cm to 4 cm and is known to be very mobile. It is found in warmer parts of New Zealand, and tropical regions around the world due to its travels via shipping and commerce between locations. The insect is believed to have originated in Africa.
The cockroach is often found residing indoors as well as outdoors. It is found mainly in basements, sewers, steam tunnels, and drainage systems. This cockroach is readily found in commercial and large buildings such as restaurants, grocery stores, bakeries, and where food is prepared and stored. The American cockroach is rarely found in houses; however after heavy rain infestations of the cockroach can enter homes.
Impact
American cockroaches can become a public health problem due to their association with human waste and disease, and their ability to move from sewers into homes and commercial establishments. Cockroaches are also aesthetically displeasing because they can soil items with their excrement and regurgitation.
Management
Overseas there are several hymenopteran (parasitic wasps) that are natural enemies of the American cockroach however; there are no records of this occurring in New Zealand.
Removal of rotting leaves and limiting the moist areas in and around buildings can help in reducing areas that are attractive to these cockroaches.
Other means of management are insecticides that can be applied to basement walls, wood scraps, and other infested locations. Residual sprays can be applied inside and around the perimeter of an infested structure. When insecticides and sprays are used to manage cockroach populations they may ultimately kill off the parasitic wasps. Loose, toxic, pellet baits are extremely effective in controlling America cockroach populations.
Resources
The Ohio State University Extension Fact Sheet
Page last updated: 14 July 2008