Termites in Honolulu: Oahu's Formosans, Asian Termites and Drywoods

Honolulu is where Hawaii's termite story starts. The Formosan termite was first officially recorded here, the Asian subterranean termite was first found here, and University of Hawaii researchers in Manoa have spent decades tracking all of them. Here's what that research tells an Oahu homeowner.

By John Updated 4 min read Termite pressure: Very heavy
Sketch map of the Hawaiian Islands with a pin on Honolulu on the island of Oahu

The short version

Oahu has Formosan subterranean termites almost everywhere, Asian subterranean termites established around Ewa and Kalaeloa, and West Indian drywood termites in buildings. A UH study found Formosan swarmers on Oahu from April into July or August, peaking in May, with Asian subterranean termites flying about a month later. Honolulu covers all of Oahu.

Honolulu at a glance

Termite pressure
Very heavy
Termites to know
Formosan subterranean, West Indian drywood
Why termites like it here
Warm and humid year-round, with Formosan termites widespread across Oahu, Asian subterranean termites established on the Ewa plain and drywood termites in buildings islandwide.
Inspection report for home sales
Termite Inspection Report (PC-9)
On this page
  1. Where Oahu's termites came from
  2. When Oahu's termites fly
  3. When termites swarm in Honolulu
  4. Light, wind and rain
  5. Honolulu's two termite problems
  6. Research down the road
  7. For Honolulu homeowners
  8. Questions

Where Oahu's termites came from

Honolulu is the first place in Hawaii with an official Formosan termite record, from 1913. University of Hawaii Extension says the termite is now widespread on Oahu.

Oahu has collected more termite species than the other islands. A 2017 UH survey of termite distribution and flight periods on Oahu, led by Reina Tong and J. Kenneth Grace, lays out the island's main pests:

  • Formosan subterranean termite, the most costly termite in Hawaii and widespread across the island.
  • Asian subterranean termite, first found in Hawaii in 1963 in Kaimuki and now established in the Ewa and Kalaeloa areas, where it causes severe damage.
  • West Indian drywood termite, the second most costly termite in Hawaii. The study notes that Oahu's Nanakuli area has the only known natural infestation of this species outside its native range.
  • Western drywood and Indo-Malaysian drywood termites, each found at only a few Oahu sites so far.

When Oahu's termites fly

From light-trap catches across Oahu in 2011 and 2012, reported by Tong and colleagues at UH Manoa.

Termite flight periods on Oahu
Termite Months with swarmers caught Notes
Formosan subterranean April to July in 2011; April to August in 2012 Peak in May; fewer on windy nights, more after rain
Asian subterranean April, June and July 2011; June 2012 About a month after the Formosan peak
West Indian drywood April to June in 2011; April to July in 2012 Light traps may help track it
Western drywood Not caught in light traps Flies by day and may not be drawn to lights

The traps were mostly at low-elevation, coastal sites. The researchers recommended adding sites on Oahu's north and west sides.

When termites swarm in Honolulu

The chart shows the Formosan and West Indian drywood termites. Expect the Asian subterranean termite's flights to run about a month behind the Formosan peak.

Typical swarm months for Oahu's two biggest termite pests
Termite J F M A M J J A S O N D
Formosan subterranean Dusk, in big clouds around lights some swarms peak peak some swarms
West Indian drywood Night, toward lights common peak common

Light, wind and rain

The Oahu study found patterns a homeowner can use. Wind cut down Formosan flights: nights with higher average wind speeds had fewer swarmers. Rain did the opposite: more rain went with more swarmers. And swarmers came to lights in large numbers, which is how the study counted them.

The researchers also enlisted citizen scientists, students and a household, to run light traps, and suggested that light trapping could help track the West Indian drywood termite and might even reduce the number of swarmers dispersing. For a homeowner, the practical version is simpler: on still, humid May evenings after rain, keep outdoor lights off and close the screens. Statewide swarm basics are on the Hawaii termite page.

Honolulu's two termite problems

Oahu houses usually face two different termite jobs, and they're handled differently.

Subterranean termites, Formosan and Asian, come from the soil and need moisture, and Formosans fill hollow spaces with carton nests. Protection is at the ground: soil treatment, physical barriers like the Basaltic Termite Barrier developed at UH Manoa, bait systems and sealed slab penetrations. See Formosan termite treatment.

Drywood termites live entirely inside dry wood and leave pellets. UH's Ken Grace notes the West Indian drywood termite is largely controlled by tent fumigation, and that injecting insecticide into wood works for small infestations but is difficult. See termite tenting and drywood termite treatment.

A house can have both. Ask an inspector which one they found, and get the PC-9 report that shows where.

Research down the road

Honolulu homeowners have an unusual neighbor: the UH Termite Project at the College of Tropical Agriculture and Human Resources in Manoa, funded by the USDA Agricultural Research Service under the slogan "Educate to Eradicate." Its work on Oahu's species, flight seasons and controls is where most of the facts on this page come from.

For Honolulu homeowners

Do

  • Keep outdoor lights off on still May and June evenings
  • Ask whether a finding is subterranean or drywood
  • Check furniture, frames and attics for pellets
  • Get the PC-9 report with a diagram

Don't

  • Assume swarms are over after May; Asian termites fly later
  • Move recycled lumber or pallets without checking them
  • Let soil or plants touch wood siding
  • Treat drywood termites with a soil treatment

Questions people ask

When do termites swarm in Honolulu?

Formosan termites swarm on Oahu from about April into July or August, peaking in May. Asian subterranean termites fly about a month after the Formosan peak, and West Indian drywood termites from April into June or July.

Are there Asian subterranean termites in Honolulu?

Yes. The species was first found in Hawaii in Kaimuki in 1963 and is now established in the Ewa and Kalaeloa areas of Oahu, according to UH researchers.

Do drywood termites live on Oahu?

Yes. The West Indian drywood termite is the second most costly termite in Hawaii and is mainly controlled by tent fumigation. Other drywood species have been found at a few Oahu sites.

Who licenses termite companies in Honolulu?

The state Pest Control Board, part of the Department of Commerce and Consumer Affairs. You can check a license on its public license search.

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