This document contains information about the biology and management of the German cockroach. A wide range of management options is listed. From this list, the IPM Practitioner can choose options to develop a unique management plan for each particular customer site.
Management Objectives for the Pest at the Particular Site
What do you want/need to accomplish at the site in regard to the German cockroach?
The answer to this question will vary, depending on the site and the customer. Some examples are
- Reduce cockroach complaints in the building and work with occupants to prevent future complaints.
- Keep the number of cockroaches caught in sticky insect monitors at a certain level
- Help client comply with Health Department regulations
- Adults are pale to medium brown and about ½ to 5/8 inch long.
- Adults have 2 dark stripes running parallel to the body on the upper surface of the first segment of the thorax (called the “pronotum”).
- The young are smaller and darker than the adults.
- The most prominent marking on a young German cockroach is a single light stripe running down the middle of the back.
- Adults have wings, and young have varying sizes of wing buds.
- Adult females carry their egg capsule (called the “ootheca”) protruding from the rear of their abdomen until about a day before it is ready to hatch.
- The egg capsule is about 1/3 inch long and contains between 30 and 48 eggs.
Why the German Cockroach is Considered a Pest
- Cockroaches contaminate food and eating utensils.
- In general, cockroaches are not associated with severe illnesses or disease outbreaks, but cockroaches can transmit organisms that cause gastro-intestinal distress and food poisoning as they wander over food and utensils.
- Cockroaches are a source of allergens that can trigger life-threatening asthma attacks in some people.
- They can destroy fabric and paper products.
- Most people are disgusted by the thought or the actual presence of cockroaches.
Special Regulatory Conditions
California Health and Safety Code Sections that relate to mice and cleanliness in food establishments:
114010. “All food shall be prepared, stored, displayed, dispensed, placed, transported, sold, and served as to be protected from dirt, vermin, unnecessary handling, droplet contamination, overhead leakage, or other contamination.”
114030. “A food facility shall at all times be so constructed, equipped, maintained, and operated as to prevent the entrance and harborage of animals, birds, and vermin, including, but not limited to, rodents and insects.”
114040. “The premises of each food facility shall be kept clean and free of litter, rubbish, and vermin.”
114050. “All food facilities and all equipment, utensils, and facilities shall be kept clean, fully operative, and in good repair.”
Biology and Behavior of Cockroaches
To be successful, management strategies must take into consideration the biology and behavior of the pest. Understanding the biology of a pest can reveal weaknesses and vulnerabilities that can be exploited when trying to manage the pest
- The German cockroach is native to a warm, moist climate, probably tropical Africa, and is now found in every state in the U.S.
- The German cockroach is unable to survive away from the warm, moist, food-rich habitats provided by humans inside buildings and other structures.
- German cockroaches have 3 distinct life stages: egg, nymph, and adult.
- Adult females carry the egg capsule around with them until about a day before it is ready to hatch. This increases the chances of more of the young surviving.
- The egg capsule hatches into many tiny nymphs that resemble the adults but are smaller, without wings, and cannot reproduce.
- The nymphs molt (shed their skins and grow a small amount) 5 to 7 times, depending on the temperature and availability of food and water, before reaching adulthood.
- The process from egg to adult takes around 100 days, again depending on the temperature and availability of food and water.
- The German cockroach has a “high reproductive potential” because
- It has a greater number of eggs per egg capsule than other species that infest buildings
- It takes the shortest time to develop from egg to sexually mature adult
This means that the numbers of German cockroaches in an area can build up rapidly.
- Their high reproductive potential allows German cockroaches to become resistant to pesticides more quickly.
- German cockroaches are smaller than other species and therefore can find many more hiding places in the same amount of space.
- The German cockroach avoids light and usually does most of its foraging for food 3 hours before dark and 1 hour before it gets light. However, cockroaches can learn different foraging schedules in order to avoid human activity.
- The German cockroach will eat almost anything, including its fellow cockroaches and their droppings.
- For survival, water is much more critical to the German cockroach than food. If water is present, the adults can live for weeks without food.
- In the absence of both food and water, adults die in less than 2 weeks.
- The German cockroach prefers hiding in tight or narrow spaces especially where it is warm and moist. Kitchens, bathrooms and electrical equipment are favorite places. Clutter vastly increases the amount of harborage available. Attractive harborage includes
- Cracks and crevices in walls, floors, cabinets, furniture and appliances
- Inside the corrugations of cardboard
- Within stacks of newspaper or paper bags
- Younger stages of nymphs and females carrying egg capsules are more likely to stay close to their harborage when looking for food.
- Older nymphs and adults will search more widely for food.
Factors that Favor the German Cockroach
- Poor sanitation provides large quantities of food for cockroaches and makes them less likely to feed on poison baits, and thus harder to control.
- Leaks and other sources of moisture provide cockroaches with abundant water.
- Clutter provides abundant hiding places for cockroaches.
- Poor building maintenance can provide cockroaches with access to structures, harborage, water, and easy pathways from room to room within the structure.
- Little or no inspection of goods coming into the structure can allow cockroaches to hitchhike into the building.
Monitoring and Record Keeping
The purpose of monitoring is to track pest activity in order to catch small problems before they become overwhelming. Monitoring makes it possible to properly time pest management actions and to evaluate the effectiveness of those actions. Records are kept to document the methods and products used and to record information that can be used to fine-tune pest management methods and plan future actions.
Sticky insect monitors and careful visual inspection work best for monitoring the German cockroach.
The “tolerance level” is the number of German cockroaches that triggers action to control the pest. The tolerance level is site-specific and differs depending on the customer, the location, and other factors. Determining the tolerance levels for a site helps prioritize work that must be done to control the pest.
Pests need food, water, and shelter to survive. Pests also need access to a structure and a way to move around within the structure in order to make themselves a nuisance inside a building. If even just one of these factors can be reduced (or eliminated), the environment will support fewer pests, and pests will be less likely to invade our living spaces.
To limit availability of food and water
- Food preparation and eating areas should be thoroughly cleaned daily. Drain sinks and remove all food debris. Do not leave food preparation and eating areas dirty overnight.
- Discuss the importance of sanitation with the appropriate people.
- Regularly steam clean large appliances in commercial kitchens.
- Periodically give all food preparation areas a deep cleaning focusing on drains, vents, deep fat fryers, ovens, and stoves. Steam clean drains and infested appliances. Use a vacuum cleaner to capture cockroaches driven out by the steam.
- Use plastic liners in waste receptacles.
- Remove garbage containing food wastes from the building before nightfall or tie a knot in the plastic liner.
- Store garbage in closed, rodent-proof dumpsters or garbage cans outside the building.
- Keep waste receptacles and dumpsters clean.
- Clean cans, bottles, and other recyclables before storage and remove them from the building before nightfall.
- Store food in the refrigerator, freezer, or cooler, or in roach-proof containers such as Tupperware or screw top jars (screw-top jars are not roach-proof unless the lid has a rubber gasket).
- Store dry pet food in roach-proof containers.
- Discourage people from storing food in desks or lockers. Insist that food in personal spaces is stored in roach-proof containers.
- Limit areas where food can be eaten and make sure to clean those areas after holiday, birthday, or other kinds of parties.
- Remove and clean pet dishes after pets have eaten. Do not leave pet food out over night.
- Fix all leaking faucets and pipes.
- Drain and/or ventilate moist areas.
- Keep food preparation areas dry when not in use, especially over night.
To limit availability of shelter/harborage
- As much as possible, eliminate clutter:
- Break down corrugated cardboard boxes and store them away from vending machines and food storage and preparation areas, preferably in a cool or cold spot.
- Remove stacks of newspaper and paper bags, especially in food storage and preparation areas or near vending machines.
- Keep storage closets and other storage areas well-organized and clean.
- Remove excessive stored goods and others items that result in clutter.
- Caulk or otherwise seal cracks and crevices, first in areas where cockroach populations are highest. As time and money allow, work on other areas that provide good cockroach harborage.
- If gaps cannot be sealed, they can sometimes be widened to make them unattractive to cockroaches. For instance, the space between free-standing shelves and adjacent walls can be widened by moving the shelves one inch away from the walls.
Physical controls employ physical means to remove cockroaches or prevent their movement within a structure.
- Sticky insect monitors are very effective in capturing cockroaches, but they usually cannot solve a cockroach problem by themselves.
- Vacuuming has an immediate impact on the cockroach population and reduces the level of allergens.
- Sealing gaps in walls around plumbing and electrical conduit is very important to keep cockroaches from moving along these “roach highways” from one room to another.
- Foam insulator sheets inserted behind electrical face plates will seal off cockroach access and reduce infiltration of hot or cold air.
- Screening and weather-stripping windows and doors can prevent German cockroaches from walking out of a window or door and moving up or down the outside of a building to get to another floor.
- Chemical controls are used to directly suppress a cockroach population.
- Dusting Agents (Note that these can remain effective for very long periods of time as long as they don‘t get wet.)
- Boric acid dust can be used in wall voids, in cracks and crevices, and under appliances. Cockroaches are not repelled by this dust.
- Nic 325 is a combination of limestone and corn gluten meal and acts mainly as a repellent. It can be used in wall voids, in cracks and crevices, and under appliances.
- Diatomaceous earth works by absorbing the outer waxy coating on an insect’s body, which allows water to leaks out of the insect and causes death by dehydration. Diatomaceous earth can be used in wall voids, in cracks and crevices, and under appliances.
- Insect Growth Regulators (IGRs)
- IGRs do not kill cockroaches directly. They cause immature cockroaches to become sterile adults that die without reproducing. Affected cockroaches often have twisted wings.
- Cockroach Baits
Baits work best where sanitation is good so that the bait is not competing with freely available cockroach food. Using baits reduces the amount of pesticide in the environment because small amounts of bait, containing minute amounts of pesticide, are placed only in areas where cockroaches are likely to feed.
The IPM Partnership
The PCO-Customer Partnership is Very Important
IPM works best when the customer and Pestec form a partnership to tackle the pest problem. The German cockroach cannot be managed satisfactorily without the cooperation of the customer, especially in the area of sanitation. Pestec will discuss the findings of the initial inspection and any subsequent monitoring sessions with the customer to determine which issues and tasks will be the responsibility of Pestec and which will be the responsibility of the customer.
Information is a powerful tool in IPM. Information can help change people’s behavior, particularly in how they store food and dispose of waste. Changing these behaviors is a necessary part of managing cockroaches. Occupants of buildings and homeowners can also help in the early detection of pests so that Pestec can be alerted before the problem is severe.
Pestec’s highly trained and knowledgeable staff can provide pest management education or training sessions for facilities managers, risk managers, building occupants, homeowner associations, and others.