The Fight to Save Hawaii’s Coconut Palms

Across Hawaii, what looks like a bad haircut on the landscape is marking the slow death of the coconut palm, that icon of paradise. The culprit: the coconut rhinoceros beetle, a glossy, thumb-size scarab that bores into the crowns of palms to feed on sap. Today, all that stands between the beetle and a palm-poor Hawaii is a small team of scientists, field crews and grub-sniffing dogs.

When the coconut rhinoceros beetle, or CRB, first arrived in Hawaii more than a decade ago, the threat seemed under control. But in recent years the beetle has spread. Palms near Waikiki have been showing signs of the beetle — V-shaped cuts in their fronds, bore holes in their trunks — prompting officials to treat hundreds of Honolulu’s palms with insecticide. This spring, traps set on the Big Island caught 10 beetles.

The beetle can still be eradicated on the Big Island, but on Oahu and Kauai, containment is the only option. The work falls to the Coconut Rhinoceros Beetle Response, an Oahu-based organization focused on creating 1,500-foot “exclusion” zones around high-risk sites — airports, harbors, compost facilities, plant nurseries and the like — to intercept beetles before they proliferate. The team sets traps, treats palms and tests ways to kill the beetle. And to find the larvae, they deploy two trained dogs, Bravo and Penny. All told, the dead-beetle tally is at least 144,503.

One morning in May, Keith Weiser, deputy incident commander for CRB Response, drove to a military housing neighborhood near Pearl Harbor to observe a field crew. A dead beetle in a bottle rattled in the cup holder. The smell, akin to that of spoiled shrimp, filled the cab. “Usually bugs dry out so quickly,” Dr. Weiser said. “But these guys are so big they actually rot.”

Outside a house with a single coconut palm in the yard, two crew members unloaded what amounted to an arboreal first-aid kit: an air-powered, piston-driven syringe, some insecticide and a drill. One of them sanitized a drill bit, bored a hole in the palm’s trunk and inserted the syringe to deliver imidacloprid, the insecticide, to the tree’s circulation system. (The team avoids flowering trees to reduce risks to pollinators.) It takes about a month for the insecticide to reach the crown of the tree, at which point it kills any beetles unfortunate enough to make it that far.