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CUES: Center for Urban Ecology and Sustainability

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Disruption of areas containing or attracting pests must be resolved in order to create a sustainable urban environment. Often insects may be vacuumed up and disposed of in a sealed container. Where it is not feasible to vacuum such as with flying insects or when infestations are not in accessible areas, it may be necessary to chemically control the pest insects.

Prior to any chemical controls, make the surrounding environment less desirable to pests. This involves sealing or repairing any holes, cracks and gaps noted during inspection with appropriate products such as caulk or spray foam. Clean up and remove all available food from infested areas. Clean up all spills, food deposits, decaying organic matter, puddles, and other potential sources of pest nourishment. A structure that is thoroughly cleaned and maintained on a regular basis will not support most pest insects and should be a goal of anyone seeking to maintain a sustainable urban environment. 

Chemical controls often target the nerves of the insects. Below is a link to some explanations as to how insecticides kill insects. This is important to know especially if you will utilize traditional pesticides for treatment.


Product Formulations


Use spray products when you want to quickly knock down a variety of different pests. When choosing a spray to use, be aware of the many biorational or less toxic sprays currently on the market. The product should be chosen by carefully reading labels and Material Safety Data Sheets. Some products may be ordered online, but others may have limited availability in your area. Initially choose a biorational type product unless the pest poses an immediate health risk (e.g., yellow jacket nest on your home). Before purchasing a product, take the following points into consideration.

  • Only use a product if the pest and application site are listed on the label.
  • Be careful applying water based products near electrical lines and oil based products near potential ignition sources (e.g., pilot lights).
  • Most ants are not treated best with sprays; certain types of ants will even split into multiple colonies after getting sprayed, making the problem worse.
  • Note that certain sprays may stain certain surfaces such as wood, carpet, and plastic so apply a small amount to a concealed area and wait prior to treating entire area.
  • Many plant based products also have strong odors. While most smell quite pleasant initially, it may be necessary to circulate air through the area after treatment.
  • Some products only kill by direct contact with the spray; others will remain active as wet droplets; and some remain active for weeks after drying. Choose your product carefully. 

If the biorational products and techniques presented on this website did not eradicate the pest, more toxic approaches may be necessary. Before purchasing a traditional insecticide product, read the labels thoroughly and choose a product that has target pest and site listed on the label along with an acceptable toxicity profile to non-target organisms (i.e., humans, pets, wildlife). An aerosol can of a product containing a pyrethroid (active ingredient ends in "-thrin") will be preferred for most applications. These products will kill effectively for weeks after the spray has dried. Refer to specific pest descriptions for further application guidelines.


Insecticide bait consists of one or more insecticides mixed in a food base to cause insects to ingest the toxins. Because the insecticide enters the insect's body through the digestive system rather than the integument, less insecticide is required for a lethal dose. That is, the toxicant (active ingredient) is applied at a much concentration per unit volume than most sprays. When choosing a bait, determine the relative importance of cost, ease of application, and lasting effectiveness of the various available bait formulations. Below is a table showing the different bait formulation properties.

Form Advantages Disadvantages
Paste Inexpensive, Easy to Make Dries quickly, Some Harder to Apply
Granule Heat Stable, Easy to Disperse or Containerize Non-Sticky (No Vertical Surfaces)
Liquid Inexpensive (mainly for ants) Must be Containerized or Placed as Small Drops
Gel Easy to Apply, Lasts a Long Time More Expensive

Gels are most preferred but usually cost more than pastes or liquids. Granular baits are best used outdoors scattered along the perimeter (away from children and pets) or secured in containers staked in the ground. Inside, baits are most useful against two residential pests found in the north central United States, ants and cockroaches. Ants and cockroaches each require different baiting strategies.  


  • Apply bait along trails in containers or areas inaccessible to pets or children. Do not interrupt the trail; place within a couple inches of the ants.
  • If bait placements are successful, you will see trails of ants harvesting the bait and bringing it back to the nest. Ants need to bring enough bait back to the colony to poison the queen.
  • Your ant in question not like the particular formula or placement of bait so try several baits simultaneously as many small placements in infested areas or collectively in appropriate containers.
  • Ant baits take several weeks to several months in order to eradicate a colony. Do not place ant baits in non-infested areas where ants are not desired as baits can lead ants further into the structure.
  • Deny ant access to potential food sources in order to help ensure baits will work successfully.
  • A simple ant bait container can be made by partially filling a drinking straw with liquid ant bait and placing it on an edge near the trail.
  • Other areas to apply small drops of liquid ant bait include electrical outlets, holes in walls and floors, and sink overflows.
  • Gel baits may also be placed alongside trails at regular intervals taking care not to block the trails themselves.
  • Outdoors, granular ant baits may be placed in containers or along perimeter of the structure. Exterior bait vessels can be made out of small plastic (label "no food") containers with holes cut in it small enough to allow ant access while preventing access by non-target organisms. Ideally the container should be secured in place and covered with a large lid to protect from the weather.


  • For cockroaches, baiting is usually necessary only inside a structure.
  • Place small amounts of gel bait (pea sized or less) along edges, in cracks, crevices, and holes in regular intervals (at least every 2 feet). Ensure that all bait placements are made appropriate to label instructions and are inaccessible to children and pets.
  • Bait placements may be smeared into place with a clean non-porous glove to improve the bait texture as it dries, making dried bait more easily consumed.
  • Pre packaged bait stations may also be utilized in sensitive areas where it is not possible or desired to apply gel baits.
  • Note where all bait is applied as it will need to be removed once the pests are eradicated.
  • Cockroach baits generally take at least several weeks to eliminate a population. It is important that there are no sources of alternate food for the cockroaches or baiting will not be as effective. Also, some cockroaches may not be controlled by baits alone so dusts may be utilized concurrently with baiting.



Dusts are a useful tool to use with baiting to control cockroaches. Boric acid dust is picked up by cockroaches and ingested while the cockroach grooms itself. The exact mode of action is not known, but boric acid has been an effective tool in cockroach control for many years. 

  • First use a dust that contains a high percentage (>90%) of boric acid.
  • Use a bellow or bulb duster to apply dust lightly to cracks, crevices, and voids where cockroaches may inhabit.
  • Proper applications should be visible as no more than a very light layer (not white). 
  • Boric acid remains active indefinitely unless it gets wet so one treatment will generally suffice in enclosed areas.
  • Ensure that boric acid dust is not applied on or near plants as it is relatively toxic to many plants.


The nests of pests such as wasps and yellow jackets may be controlled very effectively with dusts that contain pyrethrins or pyrethroids. Remember to identify the pest prior to treatment as certain species of bees may be protected in your area. If you are allergic to wasps or related species, do not treat these pests as stings are not uncommon during treatment. Use the following application guidelines listed below. 

  • Use a "bee pole" to apply the dust from a distance; wear appropriate personal protective equipment (gloves, goggles, dust mask, boots)
  • Where thick clothing with a hood and long sleeves and pants. You can seal your shirt and pant cuffs with duct tape and tie your hood to further reduce stings.
  • Treat the nest before sunrise (preferred) or after sunset when the wasps are least active.
  • Ensure that all people and pets are out of the area and all windows and doors are tightly shut near the nest.
  • Apply a liberal amount of dust to the nest, with a lot in the exit hole.
  • A spray foam may be used instead if the proper dust is not readily available. 
  • Leave the nest attached for several days to ensure all pests are dead.
  • Properly dispose of nest taking into account the amount of insecticide applied into the nest.

Product Information

Modes of Action


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Last modified on May 08, 2013