The Smokybrown Cockroach, Periplaneta fuliginosa¹

D. R. Suiter and P. G. Koehler²

APPEARANCE

The smokybrown cockroach is closely related to the American cockroach , but is a uniform shiny, dark-brown or mahogany color. It is about 1 1/4 to 1 3/8 inches long and the wings of both sexes cover the abdomen (Figure 1). The female has a broader abdomen than the male and lacks styli. Young nymphs have white markings on the thorax and abdomen, and on some antennal segments. Older nymphs are uniformly dark brown.

smokybrown cockroach.

American cockroach.

Figure 1.

HABITAT

The smokybrown cockroach has become a major pest in many parts of the U.S., especially in the moist Gulf states and southern and eastern portions of the Mississippi valley drainage pattern. The smokybrown cockroach was reported in Florida 150 years ago and can comprise up to 77% of cockroach trap catches around suburban homes.

Smokybrown cockroaches are prevalent in leaf litter, in and around shrubs, flowers and trees, tree holes, wood piles, garages, crawl spaces, attics, and greenhouses. It has also been found on roofs and in rain gutters feeding on bird droppings and plant materials. Smokybrown cockroaches can also survive in sewers.

BIOLOGY AND HABITS

The smokybrown cockroach life cycle requires about 320 days from egg to adult. The eggs are laid in an ootheca that is 1/2 inch long and is dark brown in color. Incubation averages 45 (24-70) days. An average of 20 nymphs hatch from each ootheca. Adults live 2-6 months and are strong fliers attracted to lights at night.

Smokybrown cockroaches have a greater tendency to lose moisture through the cuticle than other cockroaches, and thus require liquid water every 2-3 days. Detailed studies on the spatial distribution (focality) and mobility of smokybrowns in north central Florida has indicated that populations are tightly centered on habitats that can be described as protected, moist, dark, relatively warm, and relatively free from the dessicating effects of air flow — these environmental conditions are most stable in treeholes and canopies of palm trees. Additional environments include voids in block walls, certain types of mulches (loose) and especially soffits (eaves) in attics with moisture problems resulting from inadequate ventilation or poor roofing practices. This cockroach is relatively immobile, with greater than 70% of all recaptures in a 10-21 day period involving no net movement.

CONTROL

Because the smokybrown cockroach is found outdoors, applications of insecticides to foundation plantings, wood piles, mulch, and other infested locations are recommended. Treatments placed to intercept cockroaches are both environmentally- and entomologically-sound. Residual barrier sprays have been shown to provide substantial reductions of smokybrown cockroach populations around houses. Power dusting of sewage lines, crawl spaces, false ceilings, wall voids, and trash chutes is an effective method of control. Space sprays, ULV treatment, or contact aerosols and sprays can be used in basements and utility rooms. Loose baits and other formulations better suited for damp locations can provide effective control in basements and similar areas.

Footnotes

This document is ENY240, one of a series of the Entomology and Nematology Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date October 1991. Reviewed May 2003. Visit the EDIS Web Site at http://edis.ifas.ufl.edu.

D.R. Suiter, research assistant; Philip G. Koehler, professor, Entomology and Nematology Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other extension publications, contact your county Cooperative Extension service.

U.S. Department of Agriculture, Cooperative Extension Service, University of Florida, IFAS, Florida A. & M. University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Millie Ferrer-Chancy, Interim Dean.