Koa moth (Scotorythra paludicola)

Koa moth. Photo: K. Magnacca

A sudden outbreak of the koa looper moth occurred in the Hilo and Hamakua districts of Hawaii Island in 2013. The moth defoliated koa trees (Acacia koa) over tens of thousands of acres of windward, lower elevation forests. Outbreaks of this native insect have occurred regularly on Maui but had not been observed on Hawaii Island for 50 years.  Koa trees in good health survived defoliation but with reduced growth. For more information see the Hawaii DLNR Division of Forestry and Wildlife’s koa moth fact sheet. More photos of the moth, caterpillars, damage to leaves, and defoliated koa stands may be found at the koa moth gallery, Will Haines' (UH CTAHR) gallery, and at Karl Magnacca’s (DLNR – DOFAW) on-line gallery.


Haines, WP, ML Heddle, P Welton, and D Rubinoff. 2009. A recent outbreak of the Hawaiian koa moth, Scotorythra paludicola (Lepidoptera: Geometridae), and a review of outbreaks between 1892 and 2003Pacific Science 63(3) 349-369. doi: 10.2984/049.063.0305

Stein, JD and PG Scowcroft. 1984. Growth and refoliation of koa trees infested by the koa moth, Scotorythra paludicola (Lepidoptera: Geometridae). Pacific Science 34(4): 333-339

Photos courtesy of Karl Magnacca, DLNR-DOFAW

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