Landscape Architect Articles

Tree Trouble in Paradise10-17-06 | News

Tree Trouble in Paradise

The stunning flower of Hawaii?EUR??,,????'???s wiliwili tree. A tiny wasp called Quadrastichus is devastating the tree throughout the Hawaiian Islands.

Andy Graham found signs of wasp infestation in his wiliwili trees during the first week of October.

The native trees are just starting to put out leaves on Nu’u Mauka Ranch on the south slope of Maui?EUR??,,????'???s Haleakala volcano.

But the leaves Graham saw “are looking bumpy and starting to twist,” he said. “It’s terrible.”

Climate and environmental stress is affecting trees all over the world.

?EUR??,,????'??Nearly all types of trees on the East Coast have some type of disease,?EUR??,,????'?? Hawaii biologist Art Medeiros said. ?EUR??,,????'??Now we see that it?EUR??,,????'???s gradually happening to Hawaii. Almost every Hawaiian tree has something riding on its back.?EUR??,,????'??

Adult Quadrastichus wasps have iridescent wings and reddish eyes. The minuscule wasps (1 to 1.5 millimeters in length) originated in Africa, but are believed to have come into Hawaii via Taiwan. Photo: Walter Nagamine, Hawaii Dept. of Agriculture

The wasps attack only trees of the genus Erythrina, which include wiliwili trees, which are found only in Hawaii, and coral trees, species of which are used as ornamental trees and as windbreaks on the edge of fields, said Lloyd Loope, a botanist for the U.S. Geological Survey on Maui. Wiliwil has extremely light wood and is sometimes used to make canoes and surfboards.

The first sign of the wasps was on Oahu in April 2005, Loope said. By July 2005, they were spotted on Maui and now are believed to be on all the major islands.

The main hope for saving Hawaii’s wiliwili and coral trees is research being done now on a predator wasp, also from Africa.

But extensive testing by the state Agriculture Department must prove that the predator wasp will only eat the Erythrina wasp and not other beneficial Hawaii insects, said Steve Montgomery, an entomologist and conservation biology consultant.

Sources: Honolulu Star-Bulletin, Maui News, U.C. Davis IPM