OISC Warns of Invasive Naio Thrips on O‘ahu

PC: DLNR

When DLNR Chair Suzanne Case was alerted by the O‘ahu Invasive Species Committee (OISC) of their desire to do a miconia survey of her property, she readily agreed. There was no miconia, an invasive, noxious weed, but OISC did find naio thrips had infested an 18-year-old naio shrub.

Naio thrips are a relatively new pest insect in Hawai‘I, first detected in 2008. They cause scarring and ultimately kill the trees they infect. The thrips are tiny, only 1/20th of an inch long. The first symptom of infection anyone is likely to see is the curling of leafs.

“OISC and everyone working on invasive species control is worried about this tiny bug escaping from backyard plants into wild populations,” Chair Case said. “So I give props to the O‘ahu Invasive Species Committee because they are so methodical in doing their surveys, introduced by a letter, an e-mail and a phone call.”

Case encourages anyone who receives notification from OISC or any of the other island invasive species committees to respond for the protection of their own plants and property, as well as for native plants growing on public lands.

For Case, the next step was to arrange a time for an OISC field team to come out and take the bush down. A rapid response plan developed by state and federal partners—Hawai‘i Department of Land and Natural Resources, the Department of Agriculture, US Fish and Wildlife Service, US Army and the Navy—allows for the immediate removal of plants less than two meters high. Prior to being chopped down, these shrubs are sprayed with an insecticidal soap or oil, then branches are carefully clipped off and put into sealed bags for disposal.

If a wide area is infested or a landowner doesn’t grant permission for removal, the rapid response could include chemical control followed by weekly checks for the continued presence of thrips.

“OISC does an excellent job and they’re very professional about it,” Case said based on her experience. “Very knowledgeable and polite. They interact very well with the residents and explain the process very clearly.”

While the naio is now gone, Case notes happily there’s a healthy alaheʻe behind it and an ʻōhiʻa off to the side. She expects these two native plants will eventually grow in to fill the gap.

You can report invasive species sightings to the 808-643-PEST telephone hotline, the 643pest.org website, or through the 643-PEST mobile app.