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Cockroaches

Quick facts

  • Cockroaches hide during the day and become active at night.
  • Cockroaches carry diseases that can cause food poisoning or diarrhea.
  • Their saliva, feces and cast skins can irritate allergies and asthma in people, especially children.
  • Cleanliness is very important to reduce cockroach infestations.
  • It is best to hire a pest management service to treat them.

Cockroaches can be major pests in restaurants, hospitals, warehouses, offices and buildings with food-handling areas. They secrete a substance which can stain surfaces and produce bad odors. They can also destroy fabric and paper products.

How to identify cockroaches

Four kinds of cockroaches can infest homes in Minnesota:

  • German cockroach
  • Brown-banded cockroach
  • American cockroach
  • Oriental cockroach

Submit a sample to an insect specialist or a pest management expert if you have trouble identifying the type of cockroach you have.

Only a small percentage of the actual number of cockroaches in a house, are seen. Correct identification of cockroaches is important as there are many insects that look similar (e.g. long-horned beetles, crickets, leaf-footed bugs and ground beetles).

Egg cases of different species are of different sizes and colors
Cockroach egg cases
  • A cockroach has a flattened, oval body and long antennae (about the length of their body).
  • When looking at a cockroach from above, its head is hidden from view.
  • It has six strong legs covered with spines.
  • Many adult cockroaches have fully developed wings, but only few fly.
  • Young, immature cockroaches resemble adults but are smaller and do not have wings.

Life cycle of cockroaches

  • A cockroach has three stages during its life cycle: egg, nymph and adult.

  • Adults lay eggs contained within dark-colored egg cases (size and shape of a dry kidney bean).

  • Depending on the species, an egg case contains between 16 - 50 eggs.

  • Eggs hatch into young cockroaches called nymphs, that are more numerous than adults.

How to keep cockroaches out of your house

Take precautions while moving

  • When moving, use boxes and packing material from a place free of cockroaches.
  • When packing, watch for cockroaches and their egg capsules.
  • Remove and destroy any that you find.
  • Take all boxes out of the home at night and store in a place without cockroaches.
  • If storing boxes overnight in infested buildings, keep them off the floor and away from walls by placing them on chairs or tables.
  • During winter, you can store boxes in unheated locations such as garages.
  • In your new home, watch for egg cases and cockroaches that may have survived.

Remove boxes, newspapers and paper bags 

Corrugated cardboard boxes are a good source of cockroach infestations. Examine bags, boxes and luggage brought into your home for the presence of cockroaches or their egg capsules.

 To confirm you have cockroaches:

  • Place sticky traps so that they are tight against edges, where walls meet floors.
  • Place traps in areas where cockroaches are likely to occur, such as in cupboards and around refrigerators, stoves, and sinks.

You can reduce the number of cockroaches by getting rid of places they like.

  • Remove corrugated cardboard boxes, newspapers, bags and other unnecessary clutter.
  • When storing items, leave space between packages.
  • Use caulk to seal spaces and cracks where cockroaches hide. Concentrate on areas where cockroach numbers are the highest.
  • Seal spaces where plumbing or electrical wiring goes through walls with steel wool or other rough material.
  • Put covers (escutcheon plates) on points where plumbing enters the wall, to restrict movement of cockroaches.

Keep your home clean 

If you limit access to food and water, cockroaches cannot survive and reproduce.

  • Keep all food stored in a refrigerator or in insect-proof containers made of plastic, metal or glass with tight-fitting covers.
  • Do not leave pet food and water out overnight.
  • Wash your dishes, pans and utensils as soon as you are done using them.
  • Remove all food or spilled drinks from counter tops, and clean counters, sinks and tables with soapy water.
  • Vacuum floors and all cracks and crevices to remove debris and food.
  • Take garbage out daily in closed plastic containers. Keep waste containers clean.
  • Repair any leaky water pipes or faucets.
  • Recycle cans and bottles on a regular basis. 
  • Wash and clean recycling bins.
  • Air out and dry out damp places.

How to protect your home from cockroaches

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Types of cockroaches

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Jeffrey Hahn, Extension entomologist and Mark Ascerno, former Extension entomologist

Reviewed in 2018

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