WHEELER ARMY AIRFIELD, Hawaii -- On a recent day of monitoring, Stephanie Joe, invertebrate and forest pest invasive species biologist with U.S. Army Garrison Hawaii's Army Natural Resources Program, was surprised when she reached into an insect trap at the Wheeler Saddle Club and found three coconut rhinoceros beetles.
Have you seen these large black traps with buckets hanging from trees? They are traps designed to catch invasive coconut rhinoceros beetles.
Coconut rhinoceros beetles are thought to have arrived on O’ahu through an accidental introduction from Guam in late 2013. They are a pest of palm trees, especially coconut palms.
For the past 8 years, natural resources staff has checked traps on Schofield Barracks and Wheeler Army Airfield every month and has not come across any coconut rhinoceros beetles.
Matthew “Bo” Boheler realized there was something in one of the coconut rhinoceros beetle traps on Wheeler, even before the natural resources staff showed up to check on it. Boheler was at the Wheeler Saddle Club taking care of his horses.
Boheler was able to see the beetles after natural resource staff removed them from the trap, two of which were still alive.
The adults cause the real damage. They fly to a palm tree and bore a hole through it to get at the sweet phloem. Phloem is the vascular tissue in plants that conducts sugars and other metabolic products downward from the leaves.
Often, this single attack is enough to kill the tree.
The larvae are fat grubs that live in soil and mulch, and can be spread around easily when mulch is moved.
Since the adults are chunky and not known to be good fliers, staff searched for attractive breeding sites nearby. There was a nice deep and moist pile of mulch pile about 60 feet from the Wheeler Saddle Club’s coconut rhinoceros beetle trap.
As staff thought about ways to eliminate the mulch pile to prevent it from spawning more beetles, Boheler got out his tractor. He proceeded to spread the mulch until it was a thin layer (less than an inch high), so it could no longer support coconut rhinoceros beetles.
Community members are reminded to be aware of coconut rhinoceros beetles and the damage they can cause. Anyone who finds evidence of coconut rhinoceros beetles should file a report at https://www.crbhawaii.org/report.
For more information, including look alike species, visit https://www.crbhawaii.org/.