Hawaiian Ecosystems at Risk project (HEAR) Wiliwili on Maui: threatened by the Erythrina gall wasp

The health--and perhaps even the existence--of the wiliwili tree (Erythrina sandwicensis) on Maui is threatened by the Erythrina gall wasp (Quadrastichus erythrinae). Information about the status of EGW by island in Hawaii is also available online.

For further information, contact Lloyd_Loope@usgs.gov.

wiliwili trees (Erythrina sandwicensis) native/endemic to Hawaii

Wiliwili trees (Erythrina sandwicensis) are important native dryland forest trees in Hawaii.
wiliwili flowers (orange) (Erythrina sandwicensis) native/endemic to Hawaii

Wiliwili flowers are beautiful, and may provide critical food resources for native Hawaiian birds and insects.
wiliwili trees (Erythrina sandwicensis) native/endemic to Hawaii

Native Hawaiian wiliwili trees are endemic to Hawaii, meaning that they occur nowhere else in the world.
wiliwili flowers (white) (Erythrina sandwicensis) native/endemic to Hawaii

Light-colored wiliwili flowers provide a unique visual treat to those lucky enough to chance upon them.
wiliwili tree (Erythrina sandwichensis) native/endemid to Hawaii

Native wiliwili trees are a keystone species in Hawaii's lowland dry forest, one of the most endangered ecosystems in the world.
wiliwili seeds (Erythrina sandwicensis) native/endemic to Hawaii

The brilliantly-colored, hard, shiny seeds of the wiliwili have traditionally been used as lei-making material.
Erythrina gall wasp (Quadrastichus erythrinae) damage on Erythrina leaves

Unfortunately, the Erythrina gall wasp (EGW), a recently-introduced insect, seriously affects the leaves of the native wiliwili trees.
Erythrina gall wasp (Quadrastichus erythrinae) damage on Erythrina leaves

In Hawaii, several species of non-native ornamental Erythrina trees have been affected, as well as the native Erythrina sandwicensis.
Erythrina gall wasp (Quadrastichus erythrinae) damage on Erythrina leaves

For more information about EGW, consult the Hawaii Department of Agriculture's EGW Pest Alert Flyer View info about Adobe Acrobat PDF format or the Hawaiian Ecosystem at Risk (HEAR) project's EGW species page.
Erythrina used as landscaping trees in Queen Kaahumanu Center (Maui) parking lot

Aside from the possible irreversible loss of our native wiliwili trees, many other popular landscaping trees will be affected by the EGW.
Erythrina used as landscaping trees in Mokulele Highway windbreak (Maui)

Various Erythrina varieties are widely grown around the Hawaiian islands as specimen trees or to form windbreaks. To see examples of affected (and as-yet-unaffected) trees, see HEAR's Maui EGW monitoring page.
rainbow over wiliwili habitat

With proactive management--including initial population suppression, and--later--possibly biocontrol, it is hoped that the future of Hawaii's wiliwili can be bright and long.
In any event, this recent invasion is yet another "heads-up" that Hawaii desperately needs much-improved quarantine protection to forestall additional--under present circumstances inevitable--successful pest incursions.

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Comments?  Questions?  Send e-mail to: webmaster@hear.org

This page was created on 06 August 2005 by PT, and was last updated on 24 August 2005 by PT. Text on this page was formulated by Philip Thomas (inspired by Lloyd Loope). Images are from the collections of Forest & Kim Starr and Philip Thomas. Valid HTML 4.01!