Scotorythra paludicola Scotorythra paludicola Scotorythra paludicola, the koa looper moth, is a moth of the family Geometridae. It was first described by Arthur Gardiner Butler in 1879. It is endemic to the Hawaiian islands of Kauai, Oahu, Maui and Hawaii. The larvae mainly feed on "Acacia koa", but have also been recorded from "Falcataria moluccana", "Grevillea" and "Tristania" species. On occasion, this species develops enormous populations and defoliates entire areas with koa trees. During a recent outbreak of "S. paludicola" in 2013 on Hawaii Island, larvae were found to feed on isolated populations of the invasive tree "Falcataria moluccana" near Akaka Falls
Acacia koa there are few koa remaining which are both large and straight enough to do so today. In areas where cattle are present, koa regeneration is almost completely suppressed. However, if the cattle are removed, koa are among the few native Hawaiian plants able to germinate in grassland, and can be instrumental in restoring native forest. It is often possible to begin reforestation in a pasture by disk harrowing the soil, as this scarifies seeds in the soil and encourages large numbers of koa to germinate. Experiments at the Hakalau Forest National Wildlife Refuge have shown that ōhia lehua ("Metrosideros polymorpha")