Pest of the Month: Tropical Nut Borer
The threat of Tropical Nut Borer in Hawai‘i creates a significant threshold on macadamia nut production and proceeds.
By Damon Adamson.

The Tropical Nut Borer (TNB), Hypothenemus obscurus (Coleoptera: Scolytidae), was first identified in Hawai‘i—North Kona specifically—in 1988, with consequential studies conducted in the early 1990s. Initial studies determined TNB only affected Western Hawai‘i Island and with no other reports from Maui, O‘ahu, or Kaua‘i.
But within just a few years, TNB was found on all islands throughout the state, creating a significant threshold on macadamia nut production and proceeds. University of Hawai‘i studies conducted in the 1990s suggest a larger impact on orchards within dryer climates versus consistently wetter areas.