HONOLULU – McKinley High School will begin work on Friday, July 7, 2017, to remove six Banyan trees on its front lawn that have been significantly damaged by an island-wide infestation of gall wasps. Four damaged Banyans were removed previously in early April as a safety precaution, along with seven more since 2006. All removed Banyan trees will be replaced with Golden Trumpet (Tabebuia Chrysantha) trees. Tree removal and planting of the first ten Golden Trumpet replacements are expected to be complete by early August. Further replacement trees will be installed in future phases.
"After several unsuccessful attempts to eradicate the gall wasp infestation over the past decade, we've concluded this is our best option," said Assistant Superintendent for school facilities, Dann Carlson. "We have worked closely with our partners at the state Department of Agriculture and determined that the damaged trees need to be removed before they become a safety hazard to our students."
Gall wasps were first identified on the campus in 2005 at the same time as a wider infestation of Banyan and Wiliwili trees around Oahu. The wasps burrow into branches and lay eggs into young leaf and stem tissue. Upon hatching, wasp larvae prevent new leaves from growing and cut exit holes upon departing. Impacted trees quickly suffer a loss of growth and defoliation before dying.
Past attempts to save the impacted Banyans used a different variety of wasp, Eurytoma Erythrinae, a natural predator of gall wasps, and several chemical insecticide treatments. Neither solution was successful enough to save the impacted trees. Lobate lac scale insects were also found attacking the same Banyans, creating further damage. The upcoming tree removals will have impacted 17 of the 34 campus Banyans since 2006.
"The Banyans will be replaced with Golden Trumpet trees, which are naturally resistant to gall wasps and lobate insects," said Principal Ron Okamura. "These trees will provide similar-sized canopies, shade and a wonderful display of gold blooms every spring on our front lawn, which match McKinley's school colors."
During tree removal and replacement work, access to the surrounding areas of the campus will be restricted. The upcoming removal of the six damaged Banyans will cost approximately $19,000 and the planting of the first ten Golden Trumpet trees will cost approximately $8,500.