Well cockroach (Blatta orientalis, Periplaneta americana)

Classification
Cockroaches belong to the order Blattaria. Main species are Blattella germanica (Blattellidae), Blatta orientalis and Periplaneta americana (Blattidae). They are cosmopolitan insects and particularly 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. Species found in buildings during the day hide in damp and dark places such as cracks and crevices (e.g. between bricks, behind loose tiles, under old wallpaper, behind pictures, between furniture and walls, in pipes drainage, etc.). They are omnivorous species but as a rule they are not predators. They are heterometabolous insects, i.e. they have three stages of development: egg-nymph-adult.

Blattella germanica (German cockroach)

It is the most important species, perhaps the most common and the most difficult to combat. Adults are 13-16mm in size and light brown in color. They have 2 almost parallel stripes on the pronotum (dorsal part). In relation to the species mentioned, it is the species of cockroach with the greatest egg-producing potential. It lives for several months, often exceeding 12. The female carries the eggs in sacs (so-called ovaries), which contain 30 to 40 eggs. Breeding takes place throughout the year but is particularly favored by a moist and warm environment. They appear 3-4 generations a year.
They are located in areas with human activity. Infestations often occur in food processing and storage areas and in residential kitchens and bathrooms. Their eggs may be carried inside food boxes, cartons, machinery and appliances or materials that have been brought into buildings from unclean areas.

Blatta orientalis (oriental cockroach)
The blooms are approximately 25mm in size and glossy black to reddish brown in colour. The female lives up to 2 years and lays up to 18 ovaries in her lifetime. Each ovary contains about 10 eggs. The incubation period is 1 to 2 months and the growing period (to the flowering stage) is 12 months.
This species is found under household waste, stones, leaves, etc. In buildings, it occurs in basements, vents and drains. It can climb through water and sewer pipes to the upper floors of high-rise buildings. It prefers starchy foods as food.

Periplaneta americana (American cockroach)
The flowers are 34-53mm in size and reddish brown in color. They have moderate flight ability. Females deposit 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 residences, commercial buildings, restaurants, bakeries, areas with fruits and vegetables, hospitals, etc. During the day it prefers to stay in places such as basements of buildings, sewers, wells and other warm, dark and moist places.

Public health
They are an unsightly sight and cause phobias in modern man. Cockroaches are known carriers of serious diseases such as salmonella, dysentery, gastroenteritis, etc. They have been found to carry a large number of bacteria and fungi and are also associated with the transmission of viruses with serious consequences for humans. They alter food both directly (with their presence, their emissions, the infections they cause and their excrement), and indirectly, with the pathogenic organisms they transmit. Very often they are responsible for respiratory problems, such as asthma and shortness of breath, as well as dermatitis, itching, etc.

Modes of Management

Prevention: Cleanliness and control throughout the building is essential. Storerooms, furniture, drawers that are not often opened and 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 the proper packaging of food, organic waste should be removed every day from the
our space. Additionally, drainage wells should be maintained and accessible for insecticide applications. In sensitive areas, such as hospitals, a special area is required for receiving orders from suppliers who may also harbor cockroaches. Shielding: Measures are needed to prevent cockroaches from entering and minimizing access to suitable breeding sites. Placing screens on windows, vents, etc., closing gaps under doors and sealing cracks with plaster or silicone are
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. Because cockroaches hide during the day, better results are obtained by placing walking traps or pheromone traps. Traps will reveal the problem but also evaluate the control program.

Treatment: When an outbreak is discovered, it is sprayed directly. This is done in the sewer manholes or by moving bulky objects such as refrigerators, etc. On the surfaces where they usually move, residual spraying is carried out. There the drug should remain for a long time to kill any new person that comes into contact with the sprayed surface. In areas where spraying is impossible, such as in an electrical panel or in a food area, a special gel bait is placed. In addition to houses, especially for the German cockroach, it is necessary to apply gel to possible foci.