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(order Blattodea), any of about 4,600 species of insects, a few species of which are pests. Most cockroaches live innocuously in wild environments and are usually found in tropical or other mild climates. Cockroaches are among the most primitive living winged insects, appearing today much as they do in fossils that are more than 320 million years old.
As in other insects, the body of a cockroach consists of a head, a thorax, and an abdomen. The head has long threadlike antennae and is bent downward; the mouthparts point backward instead of forward or downward, as is the case in most other insects. The compound eyes are well-developed in most species but are absent or reduced in cave-dwelling species. Male cockroaches usually have two pairs of wings, whereas females, in some species, are wingless or have vestigial wings. The structure and large size (certain species have a wingspread of more than 12 cm [4.7 inches]) of cockroaches have made them objects of interest in the biology laboratory. Cockroaches have a flattened, oval body; long, threadlike antennae; and a shining, leathery, black or brown covering. They prefer a warm, humid, dark environment and are usually found in tropical or other mild climates, but have become widespread in heated buildings, especially city apartment buildings, in the temperate zone, and infestations can be severe. Only a few species have become pests. Cockroaches eat both animal and plant material.
Many cockroaches prefer warm, humid, dark environments and many are active at night. The females of most other species produce eggs in well-formed egg cases (called ootheca). These are sometimes held protruding from the mother’s body until hatching time is near, or they may be glued in protected areas. Usually, each ootheca contains from a few to more than 30 eggs arranged in two rows.
4 types of cockroaches are closely associated with human habitat.
American Cockroaches (Periplaneta americana), German Cockroaches (Blattella germanica)
Brown-banded cockroach (Supella longipalpa) & Oriental cockroach, or black cockroach (Blatta orientalis)
Management Practices
Many types of insecticides are available for controlling cockroaches. Most are sold as liquid or aerosol sprays, while some are formulated as edible baits or dusts. Always read and follow product instructions. This will help you to achieve optimal results while using the product safely. Many insecticides require the removal of food and utensils from treated areas. Removing such items often makes areas more accessible for treatment and prevents possible contamination by the insecticide.
Sprays – When using sprays, target the areas where cockroaches prefer to hide. As mentioned previously, this will vary depending on the species. Be sure to spray any aggregations or areas with fecal spotting. Avoid spraying walls, floors, baseboards, and countertops since cockroaches spend very little time in these areas. (Any roaches that do happen to traverse these areas are unlikely to remain on treated surfaces long enough to absorb a lethal dose.)
Baits – Most householders will achieve better results against cockroaches with insecticides formulated as baits. Used correctly, it is possible to achieve results comparable to professional extermination. Cockroach baits contain a slow-acting insecticide combined with a food attractant. Pests find and ingest the bait and crawl away to die. Non-exposed roaches may succumb as well after indirectly ingesting trace amounts of toxicant expelled in the sputum and feces of exposed individuals.
Dusts – A few insecticides used for cockroach control are applied as dusts or powders. Most familiar to householders are boric acid and diatomaceous earth. For controlling cockroaches, boric acid tends to be more effective. Roaches succumb to boric acid after crawling over treated surfaces. The tiny particles of powder adhere to the insect’s body and are ingested as the cockroach preens them from its legs and antennae. Boric acid retains its potency almost indefinitely as long as the dust deposit remains dry.
