Cockroaches

There are five species of cockroaches in California that can become pests:  German Cockroach, American Cockroach, Brownbanded Cockroach, and the Smokybrown Cockroach.  The German and Brownbanded Cockroaches inhabit buildings.  Whereas, the Oriental, Smokybrown, and American cockroaches usually live outdoors, and only occasionally invade structures.  Cockroaches are nocturnal.  They hide in dark, warm areas, especially narrow spaces where surfaces touch them on both sided.  Adult German cockroaches can hide in a crack 1/16 inch or 1.6 mm wide.  Nymphs (immature cockroaches) tend to stay in smaller cracks where they are well protected.  Cockroaches tend to gather together in corners and generally travel along edges of walls or other surfaces.  Cockroaches may transmit bacteria that cause food poisoning.  The German cockroaches are believed to be capable of transmitting disease-causing organisms such as Staphylococcus, Streptococcus, hepatitis virus, and coliform bacteria.  Some people are sensitive to the allergens produced by these cockroaches.

German Cockroach (Blattella germanica)

The German Cockroach is the most common indoor species, especially in multiple-family dwellings.  They like to be in warm, humid areas close to food sources.  They are usually found in food preparation areas, kitchens, and bathrooms.  Heavy infestations will spread to other parts of the building as well.  The German Cockroach is the fastest reproducing common cockroach, a single female and her offspring can produce over 30,000 individuals in a single year.  The female carries the ootheca (egg capsule) for most of the 30 day incubation period.  The egg capsule is light tan in color, she drops it 1 to 2 days before it hatches.  Each egg case carries about 30 young, and the female can produce a new egg case every few weeks.  Egg laying is more frequent in warmer weather.

Brownbanded Cockroach (Supella longipalpa)

The Brownbanded Cockroach is not as common as the German Cockroach in California.  They seek out areas that are very warm most of the time, preferring temperatures of about 80°.  They are often found near electrical components of appliances such as radios, televisions, and refrigerators.  Brownbanded Cockroaches prefer starchy foods (like glue on stamps and envelopes).  They are often found in offices and other places where paper is stored.  The adult males sometimes fly when disturbed, but females do not fly.  Each egg case is about ¼ inch long, and is light brown in color.  The female glues her egg cases to ceilings, beneath furniture, or in closets or other dark places where eggs incubate for several weeks before hatching.  Each female and her offspring can produce over 600 cockroaches in a single year.

Oriental Cockroach (Blatta orientalis)

size=2>The Water bug, or water beetle it is commonly known as.  It lives in dark, damp places like water control boxes, outdoor drains, basements, and damp areas under or around houses.  Oriental cockroaches forage at night in search of food and sometimes migrate into buildings.  They prefer cooler temperatures than the other species do, and they often form large populations in masonry enclosures, such as water boxes.  They usually remain on the ground floor of a structure.  Oriental cockroaches can not fly and are unable to climb smooth vertical surfaces; this is why they are so commonly found in porcelain tubs and sinks.  The female deposits dark red-brown egg cases, which are about 3/8 inch long, into debris and food located in sheltered places.  Each female and her offspring can produce nearly 200 cockroaches in one year.  It can take up to 1 to 2 years or more for a nymph to become an adult.

American Cockroach (Periplaneta americana)

The American Cockroach prefers warm and humid environments, usually with temperatures in excess of 82°F.  They are commonly found in the sewers, steam tunnels, and storm drains.  They readily live outdoors, commonly found at zoos and animal rearing facilities.  Sometimes they forage from sewers and other areas into the ground floor of a structure.  Adult females carry their egg cases around for about 6 days and then cement them to a protected surface, where they incubate for about 2 months or longer.  The egg case is about 3/8 inch long, they are brown when laid but turn black in just a few days.  Each egg capsule contains about a dozen young.  A female and her offspring can produce over 800 cockroaches in a year.

Smokybrown Cockroach (Periplaneta fuliginosa)

The Smokybrown cockroach is usually found near woodpiles, garages, water meter boxes and in or around decorative planter boxes.  They prefer to be in upper parts of structures, usually live in the attic or under shingles or siding of the structure.  The nymphs are dark brown in color and have white segments at the end of their antennae and across their backs.  The female carry a dark brown to black egg case, which is about 3/8 inch long, for about one day.  The eggs can hatch about 24 days after being laid or as long as 70 days after laying, depending on temperature.  There are 40-45 nymphs that hatch from a single egg case.