Color: light tan to medium brown except for the shield behind the head marked with two dark stripes (separated by a lighter stripe), which run lengthwise on the body.
Size: ½ to 5/8-inch long.
German cockroaches have strict moisture requirements so infestations generally develop in kitchen and bathroom areas. Cockroaches often take up residence in warm cracks and crevices that are within five feet of a water source. German cockroaches are only active during the evening hours.
During the day, the cockroaches aggregate behind refrigerators, behind baseboard molding, in cracks around cabinets, closets or pantries, picture frames, and clocks or in cabinets, drawers, stoves, and dishwashers. German cockroaches spend about 75 percent of their time in these safe harborage areas. If cockroaches are seen aggregating in corners of the ceiling or other locations out in the open, it is a sign that the infestation has reached such a high level and that there are no secluded cockroach harborages available.
German cockroaches usually prefer a moist environment with a relatively high degree of warmth. As with other species, German cockroaches are mostly active at night, when they forage for food, water, and mates. During the day they hide in cracks and crevices and other dark sites that provide a warm and humid environment. Their relatively wide, flat bodies enable them to move in and out of cracks and narrow openings with ease.
Nymph has habits similar to those of adults. They are active mostly at night but hide in dark crevices during the day. If German cockroaches are seen during day, the population is probably so large that the available cracks are already full, or food and moisture are in such short supply that daytime foraging is necessary. Such behavior indicates that the population is under considerable stress. This species usually hides in areas close to moisture and food, which means the cockroaches are generally found in kitchen and other food areas. They prefer to rest on wood rather than on metal or other smooth surfaces. If water is present adult can live about month without food, but young nymph will die of starvation within 10 days.
The German cockroach is a general feeder but is particularly attracted to fermented foods and beverages residues. They eat food of all kinds and may hitchhike into the home on egg cartons, soft drink cartons, sacks of potatoes or onions, used furniture, beer cases etc..
Sanitation, Structural Modification, and Repairs - It is difficult to keep cockroaches from entering homes via boxes, grocery bags, suitcases, and the like, but you can take steps to prevent a serious problem.
A key factor in prevention is sanitation.
Cockroaches thrive where food and water are available to them. Even tiny amounts of crumbs or liquids caught between cracks provide a food source. Important sanitation measures include the following:
- Do not leave dirty dishes overnight. Store items such as cereal, crackers, cookies, flour, sugar, and bread in airtight sealed containers. Empty garbage each evening into a sturdy container with a tightly fitted lid.
- Store food in insect-proof containers such as glass jars or re-sealable plastic containers.
- Keep garbage and trash in containers with tight-fitting lids and use liners. Keep trash cans away from doorways. Remove trash, newspapers, magazines, piles of paper bags, rags, boxes, and other items that provide hiding places and harborage.
- Eliminate plumbing leaks and correct other sources of free moisture. Increase ventilation where condensation is a problem.
- Vacuum cracks and crevices to remove food and debris. Be sure surfaces where food or beverages have been spilled are cleaned up immediately. Vacuuming also removes cockroaches, shed skins, and egg capsules. Removing cockroaches reduces their numbers and slows development. Vacuumed cockroaches and debris should be destroyed. Because bits of cuticle and droppings may cause allergies, it is recommended that the vacuum cleaner have a HEPA (high efficiency particulate absorber) filter or triple filters.
Exclusion and Removal of Hiding Places:
During the day cockroaches hide around water heaters, in cupboard cracks, stoves, crawl spaces, outdoor vegetation, and many other dark locations. They invade kitchens and other areas at night. Limiting hiding areas or avenues of access to living areas is an essential part of an effective management strategy. False-bottom cupboards, hollow walls, and similar areas are common cockroach refuges. Prevent access to the inside of buildings through cracks, conduits, under doors, or through other structural flaws.
Take the following measures if observation or trapping shows roaches are migrating into a building from outdoors or other areas of the building:
- Seal cracks and other openings to the outside.
- Use weather stripping on doors and windows.
- Look for other methods of entry, such as from items being brought into the building, especially appliances, furniture, and items that were recently in storage.
- Inspect food deliveries before putting them in kitchens.
- Look for egg cases (oothecae) glued to undersides of furniture, in refrigerator and other appliance motors, boxes, and other items. Remove and destroy any that you find.
- Locate and seal cracks inside the treatment area where cockroaches can hide.
- Consider keeping a layer of gravel about 6 to 12 inches wide around the perimeter of buildings.