David Y Ige | DLNR Press Release – New video shows how Biocontrol saved native Wiliwili trees

DLNR Press Release – New video shows how Biocontrol saved native Wiliwili trees

Posted on November 16, 2022 in Current Department News, Newsroom

(HONOLULU) – A new animated video reveals the success story of how biocontrol, a process that uses a carefully selected living organism to control an invasive species, helped save the native Wiliwili tree. The video, produced by DLNR’s Department of Forestry and Wildlife (DOFAW) in collaboration with the Alien Pest Coordination Group, also shows how biological control can continue to be an important tool in the management of invasive species in Hawaii.

In 2005, a new pest, the Erythrina gall wasp, made its way to Hawaii and quickly spread throughout the state, killing or severely damaging nearly all wild Wiliwili populations. “The sudden arrival of the Erythrina gall wasp caught us all by surprise,” says Chipper Wichman, president of the National Tropical Botanical Garden. “Wiliwili is a key species in our dry forests and almost every part of this particular tree is used by cultural workers. The loss of this species would have had a profound impact.”

But in 2008, after extensive reconnaissance in Africa for predators of the gall wasp and testing to ensure those predators weren’t affecting other species, scientists were able to safely unleash a biocontrol agent: an even smaller parasitic wasp preying on the gall wasp. The biocontrol agent successfully reduced the number of wasps to a level that did not kill the wiliwili trees and saved them from extinction.

“Invasive species cost the state millions by reducing watershed benefits, degrading agricultural land, threatening human infrastructure and being a major cause of loss of biodiversity and native ecosystems in our state,” said DOFAW Conservation Forester Rob Hauff . “Biocontrol has proven to be a safe, inexpensive and indispensable tool. The success of the Wiliwili gall wasp biocontrol is an example of what we can expect as we continue to support this type of work.”

Before releasing a biocontrol agent, researchers conduct years of exploration and analysis to ensure it does not affect species other than the invasive target species. Proposed organic controls are also subject to careful scrutiny by specialists and regulators, as well as by the public. Since the focus on safety was introduced in Hawaii in the 1970’s, the biocontrol program has had an excellent track record, with no untargeted harms released from biocontrols in the past 50 years.

Given the ongoing impact of many invasive species currently in Hawaii, new, upgraded facilities are needed to expand biocontrol research capacity. A coalition of state and federal agencies, including DLNR, the Hawaii Department of Agriculture (HDOA), the University of Hawaii, and the United States Forest Service and Agricultural Research Service, are currently discussing options for new facilities that can serve Hawaii and other Pacific island neighbors , often dealing with similar invasive species.

While talks about new facilities are ongoing, there are still new biocontrol agents that could be ready for release in the near future. Two insects including a caterpillar that feed on the weed Miconia (Miconia calvescens) and a beetle perched on the weed tibouchina (Tibouchina herbacea), could be ready for release in Hawaii within the year.

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(All images/videos courtesy: DLNR)

Animated Video – Wiliwili Trees in Hawaii: A Biocontrol Success Story: https://vimeo.com/764310295/75668bbed2

Photos – Wiliwili Trees: https://www.dropbox.com/sh/26iq4inb956i1zc/AACHgND3m0E2RBeeUS0YsNRJa?dl=0

Biocontrol Hawaii website: www.biocontrolhawaii.org

Media contact:

madison rice

communication specialist

Hawai’i Department of Land and Natural Resources

[email protected]



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