Dos & Don’ts: Odorous House Ants


August 20, 2014

  • Do the applied myrmecology.
  • Don’t  let the odorous house ants (OHA), Tapinoma sessile, invade structures and offend inhabitants.
  • Do eliminate them though the environmentally benign process of integrated pest management (IPM). The IPM process can be defined as inspection and investigation, identification, establishing threshold levels, implementing two or more control measures (cultural, physical, mechanical, professional product application), and effective evaluation.
  • Don’t misidentify the species because every subsequent step will be ineffective.
  • Do use “RED” to eliminate OHA:
  1. Restriction refers to the methods used to create unfavorable conditions for pests to take refuge and reproduce.
  2. Exclusion refers to the methods used to prevent entry into buildings.
  3. Destruction refers to the physical and chemical methods used to control the pest ants after infestations have occurred.
  • Don’t allow plantings to become bridges into structures; trim overgrowth.
  • Do eliminate standing water because OHA are attracted to water.
  • Don’t store moisture-gathering and shelter-providing lumber, firewood, rocks or other materials adjacent to structures because it encourages OHA colonization.
  • Do seal penetrating cracks, holes and joints (especially at grade level), using polyurethane foam or elastomeric caulk. Use a properly labeled dust formulation before sealing. Also:
  1. wear nonlatex gloves when caulking;
  2. hold the caulking gun at a 45° angle to the crack, and squeeze the trigger gently;
  3. ensure the caulk fills the crack, adhering to both sides;
  4. release the trigger just before the end of the crack; and
  5. smooth the caulk over the crack with your finger.
  • Do wash aphids from adjacent plantings with an appropriate pressure sprayer to reduce ant activity. Also, use the least-toxic mode of action. There are several highly effective professional products in various formulations available.
  • Don’t underestimate OHA. They are small insects, but big pests. 

[ RELATED LINK: Most Wanted: The 411 on the OHA ]

Dr. Mitchell, D.O., Ph.D., M.P.H., B.C.E., a board-certified physician and entomologist, is principal technical specialist for PestWest Environmental, as well as PMP’s Technical Editor. He can be reached at or 515-333-8923.

About the Author

MITCHELL, D.O., DVM, PsyD, BCE, is technical director of PestWest, and a frequent contributor to PMP.

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