How do you get rid of a heavy cockroach infestation?
Significant allergen reductions occur in response to dramatic reductions in cockroach infestations. Recent studies have shown that bait-based integrated pest management approaches are highly effective, even without resident education or professional cleaning.
Initial population knock-down:
- Place "crawling insect sticky trap monitors" in every room in the home. The purpose of this is not to kill the cockroaches, but to determine where they are located throughout the home. Focus heavy cleaning efforts near where traps catch nymphs.
- Vacuum thoroughly where monitors caught cockroaches. Work as a team: flush cockroaches out of voids and from behind appliances with hot air from a hair dryer and suck them up as they run out. If possible, use a vacuum with a HEPA filter.
- Clean up food sources in the open area: counters, floors, drawers, cupboards, walls, stove top, stove vent, around the stove, and around the refrigerator. Don’t use strong, smelly cleaners. Instead, consider these green cleaners.
- After the monitors have been out for at least two nights, have a PMP use pesticides according to label directions. Bait formulations are the most effective and least risk. The PMP will apply insecticide bait in all rooms where the monitors caught cockroaches. Replace the monitors with new ones when the area is treated.
- Use an insecticidal dust in wall voids and other protected areas. If dry, the dust application will remain effective for a long time. Note: if you can see the dust, there's probably too much. Always follow the label!
- Apply an insect growth regulator (available in many formulations) in areas where pregnant females are hiding.
Continued monitoring and baiting:
- Check the bait—if the cockroaches eat it all, put out more. If they are not eating the bait, try another bait product—cockroach populations do develop bait aversion.
- Vacuum thoroughly, sucking up all dead cockroaches and their eggs. Even the dead ones can aggravate asthma and allergies. Use a vacuum with a HEPA filter if possible.
- Check the monitors, replacing them as needed. Once you can go two weeks without catching or seeing any cockroaches, consider the problem solved! The unit can return to a regular inspection schedule.
Prevent future infestation
- Clean thoroughly.
- Paint walls, make repairs, caulk cracks and crevices, and replace any fixtures or appliances. For more specific recommendations, see the Pest Prevention by Design Guidelines.
- Keep monitors out to catch infestations early and let residents know how to report pests.
Read about an entomologist's experience with German Cockroaches in this popular blog post.
Note: Do not rent out a vacant unit until the monitors can be left out for at least two nights without catching an insect.