Erythrina Gall Wasp Research D.T. Fleming Arboretum

Preservation Efforts | Alani Seed Recipients - Research Reports
Wiliwili Preservation | Mapping Project & Arboretum Inventory | Seed Conservation Notes

Research - Wiliwili Preservation

October 2009
Wiliwili seedlings from the Lyon Arboretum are repotted and sprouting leaves.

They will grow in pots until 2010 and then be planted in the Arboretum expansion project when the whole 17 acres of Pu'u Mahoe will be deer fenced with a USDA grant.
Merit Granules has worked successfully on potted and young out-planted Wiliwili.
They will be cared for gall wasp free. There will be a few extra seedlings to distribute if you would like to suggest other recipients. I imagine Wiliwili seedlings will be in demand once biological control is effective.
We are honored to receive seedlings from the Lyon Arboretum seed storage experiments of Maui's rare dry land plants, as a Dry land Plant Recovery Reserve for Maui.

March 2009
The Lyon Arboretum Donates Wiliwili seedlings for Arboretum Expansion

(click to enlarge)

Tim Kroessig, & Kalani Matsumura of the Lyon Arboretum on Oahu delivered 24 Wiliwili seedlings from their Seed Storage Lab storage and germination experiments. Seed were originally collected by David Quisenberry at Kanaio, close to the Fleming Arboretum.

Mahalo to Arnold Hara and Christopher M. Jackson for sharing research results on control of the Erythrina Gall Wasp, assisting in the preservation of the Wiliwili.

Click one of these 2 Links: Final Report | PowerPoint Slideshow

November 29, 2008

Maui News
A tiny insect that attacks the Erythrina gall wasp that has devastated Hawaii's wiliwili trees is being released in the islands by the state Department of Agriculture in an effort to prevent further decimation of the native wiliwili.

CLICK HERE to read complete article

November 2008

SUMMARY REPORT - WILIWILI PRESERVATION
By Martha Vockrodt-Moran

1. The Importance of Regular Treatment: Merit Injection is recommended every 6 months to control the Erythrina Gall Wasp. Since the discovery of the wasp January 2006 at the Fleming Arboretum , Arboretum Wiliwili have been injected every 5 months as a preventative. Fleming Arboretum trees show evidence of the wasp but appear healthy. I suspect the lack of success commonly reported on Merit Injection against the Gall Wasp is due to lapse in regular application or possibly the need for early application as a preventative before damage.

2. Thorough Cambium Injections: Injection of insecticide into the tree's cambium layer is advised every 6 inches into the trunk at the base of a tree. From our trees' only partial positive response to our first treatment in January 2006 and logic, we have revised insecticide injection practice at the Arboretum.

On large trees, the trunk branches into large branches.Treating only at the base of the trunk leaves untreated cambium on the inside of these branches. Arboretum trees have since been injected every 6 inches around the trunk base as well as the cambium on the inside of the large branches branching from the trunk.Tho this treatment may be beneficial for all branches over 6 inches, Arboretum trees have been treated from the ground (without the use of ladders) up to approximately 4 feet.

Merit-injected Wiliwili tree, May 2007

WILIWILI PRESERVATION: The Battle Against the Erythrina Gall Wasp
By Martha Vockrodt-Moran

The Fleming Arboretum has two large Wiliwili - one planted in 1952, the oher in 1976. The following are notes on an every-5-month-treatment of these Wiliwili using the Merti Systemic Insecticide.

Jan 1, 2006: First sighting of Gal Wasp stings.

Jan 12, 2006: Merit injections made into large trunks bases every 6 inches.

Feb 2006: Older, larger WiliWili shows less response.

May 25, 2006: Merit injections - 6 inch intervals on all branches up to 5 feet.

June, 2006: Trees show galling but doing okay.

Nov 28, 2006: Trees dormant - Merit injection.

Dec, 2006 - Mar, 2007: Trees still dormanat - question of dormancy or Gall Wasp effects.

Apr, 2007: New growth

May 15, 07: Merit injections

End of May, 07: Trees go into dormancy

End of August, 07: New healthy leaves

September, 07: Merit inject early… concerned that chemical would not have thoroughly traveled throughout tree during dormancy.

October, 07: All new leaves attached by galls. This may be evidence that the Merit injection in May at beginning of dormancy did not travel thru tree so new leaves in October were vulnerable.

October 24, 07: Chemical has taken effect in 6 ½ weeks. New leaves are not attached.

November thru January 08: Trees look good

February 28, 08: Merit inject

March to April, 08: Dormant

May 15, 08: Out of dormancy. New growth no damage

September 11, 08: Merit injection done late-6weeks and 11 days. We previously were averaging injections every 5 weeks tho recommended every 6 weeks on label.

October 23, 08: Gall damage

November 1, 08: Galls dead, which means it took 7 weeks for chemical injections to take effect.

Field Test Notes:

Chemical into the cambium during dormancy does not travel throughout the tree.

Wiliwil dormancy is approximately 3 months.

It takes 6 weeks for merit to travel throughout the Fleming Arboretum’s 20-25 foot tall Wiliwili trees.

5 month preventative Merit injection most successful, not 6 months as instructed on label.

Wiliwili Protection Against Erythrina Gall Wasp


Anna Palomino injects Wiliwili every 5 months with Merit systemic insecticide as a preventative against the Eurythrina Gall Wasp.	Merit injection kit


Step 1: Bark removal for plug.	Removed bark at tip of tool.


Plug and plug inserter tool.	Step 2: Inserting plu into hole in bark.


Step 3: Inserting Merit chemical into tree's cambium layer.	Step 4: Injection every 6 inches around the trunk, inluding all branches 6 inches in diameter or more.

FREE Images of Wiliwili in Bloom
By Michelle Steuermann

These Images can be Printed and/or Used for Your Desktop Background

Right click this image to download

Instructions for Printing an Image - Windows XP
(For other Operating Systems, see "Help" in top menus)

Right-click one of the images above
From the drop-down list, select (left-click) Save Picture As ...
When the "Save As" window opens revealing the "My Pictures" folder, click Save
Navigate to where you saved the image (probably "My Documents" or "My Pictures" folder)
Double-click the image to open the "Windows Picture and Fax Viewer" window
Click the Printer Icon at the bottom of the viewer to display the "Photo Printing Wizard" window
Click the Next button, select the image to be printed, and click the Next button again
Select the printer you want to use if it is not displayed, the click the Next button
In the "Layout Selection" window, click Full page photo print cropped and rotated to fit
Make sure your printer is turned on. Click the Next button, then the Finish button

Instructions for Making an Image Your Desktop Background - Windows XP
(For other Operating Systems, see "Help" in top menus)

Right-click one of the images above
From the drop-down list, select (left-click) Save Picture As ...
When the "Save As" window opens revealing the "My Pictures" folder, click Save
Click the Windows Start button at lower left of your screen, then Control Panel, then Display
In the "Display Properties" window, click the Desktop tab at top
Click the Browse button, then navigate to My Documents > My Pictures
Click the filename you downloaded (either ww-1.jpg or ww-2.jpg)
Under "Position:" click Stretch, then click the OK button

Preservation Efforts | Alani Seed Recipients - Research Reports
Wiliwili Preservation | Mapping Project & Arboretum Inventory | Seed Conservation Notes