Cockroaches (as listed in the EFET-SEAME guideline)

Ordering

Cockroaches belong to the class of Blattaria. Main species are Blattella germanica (Blattellidae), Blatta orientalis and Periplaneta americana (Blattidae). They are cosmopolitan insects and especially widespread in Greece.

Biology

Most species are terrestrial. They are active at night and hide during the day. They prefer increased humidity while living in groups in suitable shelters near food sources. The items we find in buildings during the day are hidden in damp and dark places such as cracks and crevices (eg between bricks, behind peeled tiles, under old wallpaper, behind pictures, between furniture and walls, in pipes sewerage etc.). They are omnivorous species but are generally not predators. They are heterovariable insects, ie they have three stages of development: egg-nymph-thriving.

Blattella germanica (German cockroach)

It is the most important species, perhaps the most common and most difficult to control. Adults are 13-16mm in size and light brown in color. They have 2 almost parallel strips on the pronotum (dorsal part). In relation to the species mentioned, it is the species of cockroach with the highest egg production capacity. It lives for several months, often over 12. The female lays the eggs in sacs (the so-called ovaries), which contain 30 to 40 eggs. Reproduction takes place throughout the year but is particularly favored by the humid and warm environment. They show 3-4 generations a year.

They are located in places with human activity. Infections often occur in processing areas and food warehouses and in homes, kitchens and bathrooms. Their eggs can be transported in food boxes, cartons, machines and appliances or materials that have been transported to buildings from unclean places.

Blatta orientalis (ανατολική κατσαρίδα)

The acme has a size of about 25mm and a glossy black to reddish brown color. The female lives up to 2 years and lays up to 18 ovaries during her lifetime. Each ovary contains about 10 eggs. The incubation period is 1 to 2 months and the growth period (until the thriving stage) is 12 months.

This species is found under household waste, stones, leaves, etc. In buildings, it occurs in basements, air ducts and sewers. It can be climbed by water and sewer pipes on the upper floors of high-rise buildings. Prefers starchy foods as food.

Periplaneta americana (αμερικανική κατσαρίδα)

The acme has a size of 34-53mm and a reddish brown color. They have moderate flying ability. Females lay the ovary 4 days after its formation in a protected area with high humidity. The biological cycle is similar to the previous species.

The species is found in homes, business buildings, restaurants, bakeries, areas with fruits and vegetables, hospitals, etc. During the day she prefers to stay in places such as basements, sewers, wells and other warm, dark and humid places.

Health Significance

They are an unsightly spectacle and cause phobias in modern man. Cockroaches are known carriers of pathogenic microorganisms that can cause communicable diseases such as salmonellosis. They have been found to carry large numbers of bacteria and fungi and are associated with the transmission of viruses with serious effects on humans. They can infect food with pathogenic microorganisms through their droppings, the infestations they cause and their excrement. Very often they are responsible for respiratory problems, such as asthma and shortness of breath, as well as dermatitis, itching, etc.

Management Ways

Prevention: Cleaning and inspection throughout the building is essential. Warehouses, furniture, drawers that are not opened often and are not cleaned can be ideal places for the development of large populations, while in these places insecticides are applied with great difficulty. Access to the cleaner and disinfectant is required in all areas of a building. In addition to proper food packaging, organic waste should be removed from our premises every day. In addition, drainage wells should be maintained and accessible to insecticide applications, as well as care should be taken to eliminate holes, cracks, crevices and any openings that may be a gateway or nesting point. In sensitive areas, such as hospitals, a special area is required for receiving orders from suppliers that may potentially hide cockroaches.

Shielding: Measures are required to prevent cockroaches from entering and to minimize access to suitable breeding grounds. Placing screens on windows, air ducts, etc., closing gaps under doors and closing cracks with plaster or silicone, are an important part of management measures.

Monitoring: A thorough visual inspection is required on a daily basis in all areas, which, if done correctly, will quickly reveal the problem (active monitoring). Because cockroaches hide during the day, we get better results by setting traps for walking insects or pheromone traps. The traps will reveal the problem but will also evaluate the control program (passive monitoring).

Treatment: When a outbreak is discovered, spray directly. This is done in the sewer wells or by moving bulky objects such as refrigerators, etc. Residual sprays are performed on the surfaces where they usually move. There the medicine should stay for a long time to kill any new person who comes in contact with the sprayed surface.

In places where spraying is impossible, such as on an electrical panel or in a food area, a special bait in the form of gel is applied. In addition, in houses, especially for the German cockroach, the application of gel in possible outbreaks is required.