Cockroaches are among the most common and troublesome insects that can infest our homes, including food-related commercial premises. Not only are they unpleasant to see, but they can also spread diseases and contaminate food. In this technical guide, we will explore the three most common cockroach species that infest homes and the effective strategies for eliminating them safely.
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The three most common cockroach species
- German cockroach (Blattella germanica), scientific name: Blattella germanica. This species is relatively small, with a body length of approximately 1.3 cm. It is light brown in colour and has two dark stripes running along its back. German cockroaches prefer warm and humid environments, such as kitchens and bathrooms, where they can easily find food and water. If the infested building is a bar, bakery or food-processing facility, one of their most common hiding places is around refrigerator motors. Both males and females have wings, but they are not capable of flying. This species can climb vertical surfaces very easily.
- Oriental cockroach (also known as the black cockroach) scientific name: Blatta orientalis. This species is larger than the German cockroach, reaching up to 2.5 cm in length. It is dark brown or black in colour, and males have well-developed wings, although they rarely fly. Oriental cockroaches are attracted to cool, damp and dark environments, such as basements and cellars.
- American cockroach (also known as the red cockroach) scientific name: Periplaneta americana. At approximately 3 cm in length, the American cockroach is the largest of the three species. It is dark brown or reddish-brown in colour and has a broad yellow band around the edge of the pronotum (the anatomical structure located just behind the head). These cockroaches prefer warm and humid habitats, such as pipes, ducts and the areas behind refrigerators. They can also be found outdoors near sewers and landfill sites. In Italy, they are generally found in the central and southern regions. They are excellent climbers and are among the cockroach species with the greatest infestation potential
All the species mentioned above are photophobic and therefore mainly active at night. During the day, or whenever exposed to light, they retreat into enclosed spaces. An easy way to detect the presence of cockroaches is to inspect the house or infested building at night using a flashlight. Once illuminated, they will quickly run away, making it easier to identify their daytime hiding places.
Strategies for eliminating cockroaches
Maintain good hygiene
Keeping your home clean is essential for preventing and controlling a cockroach infestation.
Removing food sources is essential. These insects feed on virtually any organic matter that humans use as food. Therefore, any food residue left on the floor becomes a food source for cockroaches.
Special attention should also be paid to stored food. Cupboards and shelves can become infested by these insects. Food should therefore be properly sealed in airtight containers, preferably stored on shelves and never left on the floor.
A cockroach infestation cannot exist if cockroaches are unable to reach food.
The same applies to commercial premises such as bars, restaurant kitchens and food-processing facilities.
The same considerations also apply to rodent infestations. If you would like to learn more, you can also read our technical guide on how to eliminate and keep mice away from your home, (available here).
Using baits and traps
Baits and traps can be effective in capturing cockroaches and reducing their population. Both gel baits and sticky traps can be strategically placed where cockroaches are most active, near food and water sources, or along walls and in the corners of rooms. These tools are control methods intended for use once an infestation is already present.
Sticky traps alone cannot solve the problem, but they are extremely useful because they perform two important functions. The first is to capture a large number of cockroaches, preventing the colony from rapidly increasing in size. The second is to act as a monitoring tool, allowing you to assess the effectiveness of the control methods adopted over time. They can also be used to detect the presence of cockroaches at the beginning of an infestation, as they are extremely effective at attracting the first individuals.
Sticky traps are generally adhesive boards that use a food attractant to lure cockroaches onto the trap (here is a good product). As a food attractant, you can use a mixture of bread crumbs and brown sugar or, alternatively, crushed biscuits placed in the centre of the trap. The adhesive is strong enough to immobilise the insect. These traps are easy to use, inexpensive, and ready to use. Once they are no longer effective, they can simply be disposed of with household waste.
Gel baits, together with insecticides, are among the most effective tools for eliminating a cockroach infestation. They consist of food attractants mixed with insecticides, most commonly in gel form. Small drops of gel are applied in the areas most frequently visited by cockroaches.
The insecticide does not act immediately, allowing several cockroaches to feed on the same bait. In addition, this strategy takes advantage of a characteristic behaviour of cockroaches: they share food with other members of the colony through regurgitation (trophallaxis). As a result, even cockroaches that were not directly attracted to the bait are later poisoned through this behaviour.
The gel is extremely easy to apply and has been designed so that it can also be used by people with no experience in pest control (here is a good product). It is slightly more expensive than conventional insecticides, but it does not require the occupants to leave the building or a business to close during application.
It is also possible to eliminate an infestation using only insecticidal gel. However, this method generally requires at least three applications over a period of at least one month in order to eliminate every individual in the colony.
The gel should be applied in strategic locations such as wall cracks, around electrical sockets, on the metal structure near refrigerator motors, on shelving units and inside cavities in general. Naturally, care should be taken not to remove the product during routine cleaning.
Applying insecticides
Insecticides can be used to eliminate cockroaches, but it is important to use them with caution and follow the manufacturer’s instructions.
Ready-to-use spray insecticides (here is a good product) can be used to treat the areas where cockroaches hide, such as cracks, crevices and behind household appliances. They should therefore be sprayed onto the surfaces that will come into contact with the insects’ legs.
Insecticide dusts can be applied in the areas where cockroaches walk, such as along walls and underneath furniture (here is a good product).
Both spray insecticides and insecticide dusts are useful for drastically reducing the size of the colony, but they are unlikely to eliminate it completely.
Both spray insecticides and insecticide dusts should be applied along the cockroaches’ walking routes, which are generally located near skirting boards and around the areas permanently occupied by the colony (pipes, inspection hatches, suspended ceilings and any other place where the colony shelters during the day).
In professional pest control, specific insecticides are used, generally based on pyrethroids (such as this one). These are contact insecticides and are applied using a pressure sprayer (like this one).
The insecticide solution is sprayed along the insects’ walking routes, particularly the areas near skirting boards, as well as the places where cockroaches shelter during the day.
The treatment is usually completed by micro-fogging the insecticide into the air. This is carried out using a machine that produces an insecticidal fog capable of penetrating every corner (such as this one).
This type of treatment is usually carried out by a professional pest control company, although most cockroach insecticides are freely available for purchase.
When these insecticides are applied, and for approximately one day afterwards, the building should remain unoccupied. In the case of commercial premises, customers should not be allowed to enter during this period.
This solution provides a very high level of effectiveness, although the return of cockroaches cannot be ruled out if poor hygiene practices continue.
In professional pest control, insecticides are usually combined with gel baits. The gel provides longer-lasting control over time.
The use of insecticides, even those approved for domestic use, must always comply with current regulations. Always follow the application rates and instructions provided on the product label, and use appropriate personal protective equipment such as gloves and a respiratory mask.
Finally, call a professional
If the cockroach infestation is widespread or persists despite your efforts, you may need to seek the assistance of a professional pest control operator. These specialists have greater experience and are much better at locating hidden cockroach colonies.
Conclusion
In conclusion, eliminating cockroaches from your home requires a combination of cleanliness, prevention and effective pest control strategies.
With proper management and the use of appropriate techniques, it is possible to eliminate these troublesome infestations and keep your home or commercial premises free of cockroaches.
The most important factor is hygiene, because no cockroach population can thrive if the insects are unable to reach stored food or any other food sources, even those accidentally left behind.