American Cockroaches

Overview

American cockroaches, Periplaneta Americana L. are worldwide-distributed pests. Despite their names, they are non-native species to America. Actually, the original home of the American cockroach is tropical Africa, but were transported to the Americas on slave/trade ships centuries ago. Like other pests, American cockroaches by their nature and relatively big size are unpleasant to most people and can inspire entomophobia ("a fear of insects or other arthropods") and cause embarrassment and possibly will lead to loss of business in commercial sectors. Because American cockroaches feed on human feces, migrate via sewers and contact unclean surfaces, they are capable of carrying and mechanically transmitting a variety of pathogenic agents that contaminate food products and cause diseases to the humans. Moreover, cockroaches in general are among common sources of allergic reactions. Recently, it has been documented that from 23 - 60% of asthmatic patients, especially children are sensitive to cockroach allergens (feces, saliva, egg cases and cast skins). Thus, the management of American cockroaches is a must wherever they occur.

Identification

Adults

• Adult American cockroaches are 1 ½ -1 ¾ inch in length. They are reddish brown with a pale band in the edges of the pronotum (the upper surface of the prothorax, the first segment of the thorax)
• They have chewing mouthparts
• Males and females are fully winged, but those of the males extend beyond tip of abdomen

• Unlike most other cockroach species, the American cockroach adults can fly (poor to moderate flier), and are also attracted to light

Nymphs

• Nymphs are wingless. After molting, they are white and then become a uniformly reddish-brown
• Early nymphal instars are uniformly grayish brown dorsally, paler ventrally, and shiny. The cerci (singular cercus- one of a pair of dorsal appendages at the posterior end of the abdomen) are slender, and distinctly tapered from the base with length about 5 times the width
• Later instars are reddish brown with lateral and posterior margins of the thorax and lateral areas (sides) of abdominal segments somewhat darker. The cerci are about the same as in the early instars. The widest segments are 2.5 times as wide as long. The antennae are uniformly brown

Eggs

• Egg capsules (ootheca) are 3/8 inch long and purse shaped
• The ootheca is brown when deposited and turns black in a day or two

Habits

American cockroaches prefer, very warm, dark and moist areas; still, they can infest dry areas if they have access to water. Because of their sizes, habits, and reproductions, they are more common in commercial buildings, food processing facilities and food storage areas than in houses. Though, in certain times of the year, especially during extremes in weather conditions, they may enter inside a house from outside sources seeking warmer temperatures, food, water or shelter. American cockroaches have flexible and elastic bodies that enable them to squeeze through tiny entry points. Generally, typical homes have several entry points that American cockroach can use to find their way into the structure. These include, but are not limited to:

• Via sewer systems
• By trees and shrubs touching the house
• Under doors
• Around utility pipes, air ducts, or other openings in the foundation

American cockroaches are usually found on the ground floor or lower levels of a building. In the US, they are the most common cockroach species found in city sewer systems, particularly around pipes and drains. Common key hiding areas of American cockroaches include the following places:

• Floor drains
• Pipe chases
• Sewers
• Grease traps
• Basements and crawl spaces
• In and around bathtubs
• Clothes hampers
• Around the manholes of sewers
• Around sump pumps
• Around steam heat tunnels
• Within warm moist piles of trash
• During summer time they may hide in cracks and crevices of porches, foundations, under decks, under mulching materials, and walkways adjacent to buildings

Biology

A mated female of American cockroaches produces an ootheca once every week. Each ootheca contains from 14 to 16 eggs. Depending on food availability, a single female produces from 15-70 egg capsules during its life span. Unlike Germasn cockroaches, American cockroach females carry their egg capsules only for about one or two days, before they glue them to a suitable protected surface with secretions from their mouths. At room temperature, eggs hatch in 50-55 days. Nymphs molt 9-13 times before reaching the adulthood. This takes approximately from 160-971 days. An adult female can live up to two years, while males live for a shorter period (up to one year). Environmental conditions such as temperature and relative humidity influence the life cycle of American cockroaches. It has been reported that nymphs move and feed at temperatures between 59.9 - 89.06°F, and stop moving at temperatures 38.48- 44.78°F; whereas adults are usually active at temperatures between 63.68 - 87.98°F and become inactive at 41.36°F. Although they prefer moisture and warmth, temperatures above 107.6°F are lethal for American cockroaches. They also do not tolerate cold temperatures as well. They die at temperatures below 15°F. During the summer months, American cockroaches can be found outdoors in yards and alleys. As aforementioned, they can enter structures and establish themselves where moisture, warmth and shelter are available. Once indoor, due their cryptic behaviors, they can squeeze through narrow cracks and crevices for safety. American cockroaches have a high reproduction rate. They are not social insects like bees, but they can form large populations in moist and warm habitats. For mating purposes, females produce a pheromone that attracts males from as far away as 98 feet. American cockroaches can run very fast. Except when threatened, they can fly short distances. American cockroaches have a symbiotic relationship with bacteria that allows them to digest cellulose. Their diet is omnivorous and will eat anything. They consume organic materials, bark, leaves, paper, wool clothes, sugar, cheese, bread, oil, lemons, ink, soap, flesh, fish, leather, other cockroaches (dead or alive), or their own cast-off skins and egg-capsules. These insects however, if they have given choice, American cockroaches prefer fermenting food. However, when food and water sources are rare, the adults can survive two or three months without food, but only about a month without water. American cockroaches are cautious and are usually active at night, but when they are hungry, they may come out searching for food during the day.

Management

Inspection

A thorough inspection is key to a successful cockroach management plan. It helps to determine the best treatment method. The purpose of an inspection is not only to sight American cockroach life stages, but also to locate the source of the infestation whether associated with sewer areas, wall voids, or any moist, warm and dark places in a building.

Monitoring

Sticky traps are usually used to detect and monitor American cockroach infestations. They also can be very helpful in evaluating the effectiveness of management strategies for this and other pests. A sufficient number of the traps should be left in common American cockroach foraging places, such as, along baseboard, near the garbage, under sinks, under and behind stoves, in the cabinets, under and behind the refrigerator, in the bathroom, in corners, etc. Sticky traps should be present at night when the cockroaches are most active. Traps are normally used indoors and not recommended for outside use as they can be deteriorated quickly by weather conditions, dust, and debris, as well as they may capture non-target organisms.

Prevention

In order to limit the establishment of an American cockroach population in a structure, employ a regular prevention program, including the following practices:

• In commercial facilities, inspect incoming materials, especially packages containing food materials brought into plant for all stages of cockroaches.  Immediately destroy infested items if found.
• Whenever possible, eliminate clutter, sheltered and dark places where roaches may hide during the day.
• Apply thorough sanitation hygiene inside and outside the structure to deprive cockroaches from access to food or water resources. This will make them more vulnerable to be in touch with pesticides, especially baits.
• Keep food in sealed containers. Do not leave uncovered food items indoors overnight.
• Eliminate sources of excess water, such as around leaky plumbing.
• Immediately pick up any spilled materials.
• Keep garbage cans tightly covered outside far from entry doors of the structure.

Exclusion

Exclusion is another pest management tool that can be used to stop American cockroaches from entering a structure. The most common pest proofing practices include:

• Screen windows, doors, and attic vents.
• Weatherproof windows and doors.
• Caulk and seal cracks, crevices, holes, openings and any potential entry points inside and outside the structure, such as openings around wires, utility pipes, doors and windows.

Physical Removal Of Cockroach Live Stages

Use strong vacuum with HEPA filter to pick up cockroach's live stages, feces, and cast skins. Properly destroy and discard vacuum contents outside the building.

Harborage Modification

Indoor

• Remove clutter from storage rooms, closets and basements, especially unused paper bags, cardboard boxes or newspaper.
• Repair peeling, or chipped paint, loose wallpaper.

Outdoor

• Remove woodpiles
• Remove excessive mulch
• Remove thick vegetation on and around buildings
• Remove empty soft drink bottles or cans

Chemical Management

 A chemical management program for American cockroaches includes the use of baits, insect growth regulators (IGR's) and when needed, EPA approved residual insecticides labeled for American cockroaches.

Baits

 American cockroach baits are usually formulated as dusts, gels, pastes, or granules. They are usually applied into cracks, crevices, and wall voids.  The placement of baits is very important and should be near cockroach harborages in corners and along edges. Baits should NOT be placed away from cockroach travel /foraging places, and on surfaces where a repellent insecticide has been applied. Most granular baits are applied outside in landscaping around the perimeter of the structure. Though, some may be applied in wall voids using a bulb duster.

Insect Growth Regulators

Generally, insect growth regulators (IGRs) for American cockroach management are professional-use-only products. IGRs act on the growth of immature stages either through contact or ingestion. As their names imply, they work by disrupting the molting and development process of nymphs and prevent them from reaching the fertile adult stage. The cockroach population then dies of abrasion. Cockroaches that have been affected by the IGR will sometimes be mutated and have twisted or bent wings. These cockroaches are sterile. Because of the slow-acting nature of IGRs, they are frequently used in combination with baits for faster elimination. To treat initial populations in steam tunnels or boiler rooms, IGRs are available in liquid formulations or point-source dispensers (the IGR is released on filter paper contained in a permeable plastic station and then transmigrates throughout the infested area). The most common IGRs (active ingredients) used in cockroach control products are hydroprene (Gentrol Point Source) and pryiproifen (Nylar). When baits and IGR are used, cockroaches may continue to be seen after treatment until the entire population is terminated. If you see some cockroaches after the treatment, "Do not be alarmed and communicate with your PMP".

Inorganic Pesticides

Inorganic pesticides are those containing no carbon. They are typically derived from minerals or chemical compounds that occur as deposits in nature. These pesticides are typically used as dust formulations and are normally applied for indoor cockroach management using a squeeze-bulb duster. For heavy infestations in large areas, a power duster can be used to treat for cockroaches. This kind of dusters uses a compressed air to deliver a large volume of dusting agents through larger voids such as attics or crawl areas. A careful treatment of dust is always required as piles of dust materials will alert cockroaches and make them avoid treated surfaces. To achieve maximum results from applications, the dust should be carefully and lightly puffed into cracks, crevices or wall voids where cockroaches are usually hiding. An organic dust can also be used for spot treatment of limited areas along baseboard, behind cupboards, or other areas where American cockroaches are active. Examples of commonly used dust formulations for American cockroach management are silica aerogel, diatomaceous earth and boric acid. Silica aerogel and diatomaceous earth are descant pesticides that absorb the waxy layer from the cuticle of cockroaches causing them to dehydrate and eventually destroy them. Boric acid is a non-repellent stomach poison that adheres to a cockroach cuticle when it walks across the dust, and then the cockroach will ingest the dust while grooming itself. Like IGRs, both boric acid and silica aerogel dusts are slow acting insecticides. This means that cockroaches will be seen for at least two weeks after an application has been made. As above-mentioned, heavy applications or more dust are not necessary. Dust applied properly in a thin layer will deliver a long, effective residual, even on porous surfaces. Repeat applications if needed, and always follow label instructions.