When Daniel Kapalikuokalani-Maile posted on Facebook last November that something was killing native naio trees in the Kapalama/Kalihi area, it prompted a rapid response from state and federal agencies and organizations.
Entomologists from the Hawaii Dept. of Agriculture (HDOA) confirmed that the tiny insect is the Myoporum thrips, an invasive species which has devastated naio forests on Hawaii island. This was the first detection ever on Oahu. Naio is an important part of Oahu’s coastal ecosystems and are popular as ornamentals in landscaping.
A quick response was mounted, thanks in great part to an Early Detection and Rapid Response Plan. In 2014 the Hawaii Invasive Species Council (HISC) provided funding to DLNR’s Division of Forestry and Wildlife (DOFAW) to draft the plan in cooperation with HDOA and Oahu Invasive Species Committee (OISC). Meetings to address the infestation included representatives from Joint Base Pearl Harbor-Hickam, O‘ahu Army Natural Resources Program, Bishop Museum, Honolulu City & County Botanical Gardens, the Honolulu Zoo, Kamehameha Schools, U.S. Fish and Wildlife Service, Oahu Invasive Species Committee (OISC) and several private citizens. They each surveyed naio on lands under their control and OISC surveyed other properties.
Of the 619 plants surveyed, only 42 showed signs of Myoporum thrips at ten different locations around O‘ahu. Seven locations have been treated which includes cutting down infested trees, spraying them with insect killing soap, tarping them, and then disposing them away from the property. Yesterday, DOFAW and OISC crews with the help from a couple of university interns finished removing 10 trees from the Honolulu Forest Reserve in the Moanalua area.
This rapid response coupled with help from people who grow naio will hopefully prevent further spread. The Oahu Invasive Species Committee is asking for anyone who knows about naio growing anywhere on the island to report it. GPS points and photographs are very helpful. Additionally, they’re looking for people willing to adopt trees and check them periodically for the presence of thrips. The insects are narrow, dark brown to black and approximately 2-2.5 mm in size. Damage on the plant is likely to be more visible than the thrips themselves.