Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

Classical biological control of the erythrina gall wasp, Quadrastichus erythrinae, in Hawaii: conserving an endangered habitat.

Abstract

Erythrina gall wasp, Quadrastichus erythrinae (Hymenoptera: Eulophidae) began a global range expansion around 2005, and is considered a significant adventive pest in Asia, Pacific islands, South- and Central America, and North America, including Hawaii. The Hawaii endemic wiliwili tree, Erythrina sandwicensis (Fabaceae) was severely impacted and threatened with extinction, leading to the release of a classical biological control agent, Eurytoma erythrinae (Hymenoptera: Eurytomidae) from southern and East Africa, in 2008. Establishment was confirmed by retrievals of wasps within 1-4 months at all release locations. throughout Hawaii, and reduced impacts to trees within two years. By 2018, the majority of trees sampled incurred less than 33% gall damage to their foliage. E. erythrinae reduced Q. erythrinae damage by >85% in some locations throughout Hawaii and may have contributed substantially to preventing the extinction of this endemic tree.