By Stephanie Joe, O'ahu Army Natural Resources Program, Directorate of Public Works, U.S. Army Garrison-HawaiiMay 18, 2015
SCHOFIELD BARRACKS, Hawaii -- Within the last year, two new insect pests, the coconut rhinoceros beetle (Oryctes rhinoceros, or CRB) and the little fire ant (Wasmannia auropunctata, or LFA) have arrived and spread on O'ahu.
Both are major pests that can hurt our native ecosystems and agriculture, and affect our households.
Thanks to the cooperation between the Oahu Army Natural Resource Program and Patrick Ching, an agronomist with the Directorate of Public Works, Schofield Barracks remains free of these incipient pests.
With continued vigilance and help from the community, it can stay that way.
-- What are they?
CRB is a chunky black beetle, about 2 inches long that arrived from Guam. In addition to the impacts it has on coconut palms, CRB also threatens other palms like the endangered loulu (Pritchardia kaalae) and crops like banana, kalo, sugarcane and pineapple.
LFA is a miniscule orange ant (just 0.06 inches long!) whose stings can cause blindness in cats and dogs. LFA came to O'ahu on infested potting material from Hawaii Island.
-- Identifying pathways of possible invasion
The first step in preventing introduction at Schofield was to identify pathways whereby CRB and LFA may be accidentally brought onto Schofield.
The CRB infestation originates at Joint Base Pearl Harbor-Hickam (JBPHH), where adult beetles live off the sap of coconut trees and lay their eggs in mulch piles. Thus, CRB can be transported by landscapers moving mulch or dead palm material after tree trimming from one place to another.
While it is possible for adults to disperse without human aid, the insects are bulky and poor fliers, making moving mulch one of the primary risks for accidentally transporting this pest elsewhere.
The Oahu Army Natural Resource Program uses coconut rhinoceros beetle traps, like the one shown above, to trap the beetles and prevent them from spreading out. The community can help curb this pest by learning about the beetle and not tampering with the traps.
After compiling a list of plant suppliers and landscapers servicing Schofield and JBPHH, the team found only one overlap and contacted the company. They warned about the risk of moving CRB onto Schofield. Fortunately, the company explained that it does not move plant material between bases and that its trucks are cleaned and power-sprayed after each job.
The team thoroughly checked the company's vehicles and confirmed this was the case.
In September, a few weeks later, a handful of CRB were found at Fort Shafter. The team suspects that these CRB have flown to Fort Shafter from JBPHH and are not yet breeding on-site. Since then, the team has instructed landscapers working at the installation to remove and treat their mulch piles.
-- Preventing invasion on a smaller scale
Like CRB, LFA hitchhikes on plant material; however, these tiny ants are much more difficult to detect being only about the size of a pinhead.
Sizeable LFA infestations have been found in Mililani and Waim�nalo and are moving around the island on potted plants and planting mix.
To tackle this challenge, the team obtained a list of nurseries supplying the Post Exchange garden shop and surveyed them for LFA. They also surveyed new housing construction on Lyman Road in Schofield where extensive landscaping is taking place. So far, LFA has not been found at any suppliers or on post.
-- Keeping pests away in the long term
To ensure CRB and LFA do not reach Schofield, the team continues surveys. LFA surveys are conducted twice a year in high-risk areas, such as garden shops and new landscaping.
The team monitors for CRB using traps that employ a pheromone and light attractant to draw in any beetles that happen to be within the vicinity of a trap.
With continued vigilance by both professionals and members of the community, we can prevent these incipient pests from becoming a permanent problem.
(Note: Joe is an O'ahu Army Natural Resources Program research specialist.)