Cockroaches

Cockroaches have been around for more than 350 million years.

There are nearly 4,000 different species of cockroaches known in the world. At least 69 species can be found in the U.S, but only about 22 species cause pest problems in homes or businesses. Only four species, which are all distributed world wide, cause frequent and significant problems in the U.S. and much of the rest of the world. These are the German, American, Brown-Banded, and Oriental cockroaches; in roughly that order of importance as urban pests.

Most species live in tropical or subtropical areas and nearly all need warm, dark, moist places to hide during the day. They nearly all will eat anything available, from sugar to rotting leaf litter to feces. They are important in recycling dead and decaying matter (especially dead plant matter) in their natural settings.

Cockroaches often are a health threat

In general, the habits and high reproductive rate of pest cockroaches can lead to large populations which spread disease organisms, contaminate and eat our food, and cause allergies and even asthma.

Cockroaches have been reported to spread at least 33 kinds of bacteria, six kinds of parasitic worms, and at least seven other kinds of human pathogens. They can pick up germs on the spines of their legs and bodies as they crawl through decaying matter or sewage and then carry these into food or onto food surfaces. Germs that cockroaches eat from decaying matter or sewage are protected while in their bodies and may remain infective for several weeks longer than if they had been exposed to cleaning agents, rinse water, or just sunlight and air.

Good sanitation and habitat reduction, along with vacuuming, surveillance, a baiting program, and some sealing of cracks can usually quickly reduce or eliminate a cockroach population. A trained, certified Pest Management Professional (PMP) has the knowledge and tools to evaluate the situation, guide and advise on sanitation improvements, and accomplish the remaining steps.

Recent medical studies have shown that cockroach allergens cause lots of allergic reactions in inner city children. They were even shown to cause asthma in children. These allergens build up in deposits of droppings, secretions, cast skins, and dead bodies of roaches.

Adequate control of cockroaches is needed in such settings to help prevent the build-up of dangerous concentrations of their allergens. Where large cockroach populations are already well established, and in older buildings, or in buildings which allow roaches to easily move between rooms or apartments, very good sanitation by one occupant will not solve the problem. In those cases, the help of a trained, experienced, licensed pest management professional will probably be needed to reduce the problem, and effectively work toward eliminating the roaches.

Profiles of the four main urban pest cockroaches. 1. German Cockroach. The German Cockroach, Blattella germanica (L.), is about 5/8-inch (16 mm) long, light-to-medium brown with two dark parallel stripes the long-way on the pronotum. Females are slightly darker, and have wider bodies, and more rounded abdomens than males. Nymphs have two dark parallel stripes the whole length of their bodies. They breed all year round indoors in humid places at about 70oF ( 21oC ). They produce 30-40 eggs in a capsule (`otheca) approximately three months after they first hatch, and then produce another capsule about every 28 days after that. 2. American Cockroach. The American Cockroach, Periplaneta americana (L.), is sometimes called the “Palmetto Bug” in tropical American areas. They are the largest of the house-infesting urban pest cockroaches at about 1.5 inches (38mm) long, with full-sized reddish brown wings and a light margin completely around their prothorax. The females have larger, heavier bodies, and the males have two obvious pairs of stylets at the tip of their abdomen. They often live in sewers and live outdoors in warm areas like Florida or southern California. They can thrive in underground steam and utility tunnels in Alaska. Under good conditions, it takes an American roach about nine to ten months to grow from hatching to maturity. After another 45 days, each mated female can produce an egg capsule containing 16 eggs every four to five days until she has produced more than 50 of them. The female usually glues her egg capsule into or onto some partly hidden spot. These are the most common cockroaches on sea-going ships. They have been noted to chew off the eyelashes, eyebrows and toenails of humans. 3. Brown-Banded Cockroach. Brown-Banded Cockroaches, Supella longipalpa (Serville), are very slightly smaller than German cockroaches (about ½-inch; 13 mm long). They have two lighter bands across their dark brownish bodies. Males have full wings, which reach beyond the tip of their rather pointed abdomens, but females have underdeveloped wings, much shorter than their broad, rounded abdomens. The lighter band markings are much more distinct in nymphs than in adults of either sex. Within a room, these roaches tend to prefer warmer, drier, and higher locations than do any of the other urban pest roaches. They are often found in upper cabinets or in other rooms than the kitchens (food preparation areas) or bathrooms. Under good conditions of moderate humidity and warm temperatures of about 80oF ( 27oC ), these roaches can develop from hatching to adult in around 95 days. The females can begin producing egg capsules containing about 19-20 eggs after about 70 more days. This species does not require as much moisture as any of the other three urban pest cockroach species. 4. Oriental Cockroach. Oriental Cockroaches, Blatta orientalis (L.), are large very dark (almost black, but sometimes dark reddish-brown), shiny cockroaches which live in sewers and similar wet, decaying organic matter. They are sometimes called “water bugs” because they come out of drains, and “black beetle cockroaches” because of their smooth, dark bodies. Males are about 1 inch long, with wings that cover only about ¾ of their abdomen; females are about 1 ¼ inch long, and have only short stubs of wing pads. They survive best at lower temperatures than the other three urban pest roach species, preferring a range of 68 to 84oF (20 to 29oC), and are seldom found in warmer states in the U.S. They grow slowly, needing more than 200 days to go from hatching to adult, and females take another 60 days to produce their first egg capsule of 16 eggs. They may go on to produce 8 to 10 egg capsules at a rate of about one every 30-40 days, depending on temperature and moisture conditions.