Maui Invasive Species Committee (MISC)

  • A A A
  • Home
  • Careers at MISC
  • Report a Pest
    • Statewide Pest Hotline
    • Little Fire Ants
    • Coqui Frogs
    • MISC Target Pests
  • About Us
    • Who We Are
    • Partners
    • Committee Meetings and Minutes
    • Strategic Plan
    • Contact Us
  • Our Work
    • Where We Work
    • Invasive Species Articles
    • Newsletters
    • Technical and Scientific Publications
    • Pest Flyers
  • Pest Species
    • MISC Target Pests
      • Rapid ʻŌhiʻa Death
      • Little Fire Ant
      • Coqui Frog
      • Miconia
      • Pampas Grass
      • Ivy Gourd
      • Blessed Milk Thistle
      • Fountain Grass
    • Common Pests
      • Banana Bunchy Top Virus
  • Get Involved!
    • Community Coqui Control Program
      • Make Your Yard Un-Friendly to Coqui Frogs
      • Community Coqui Control Code of Conduct
      • Effects of citric acid on the environment
      • Where are the coqui frogs?
    • Donate
    • Be Our Eyes and Ears
    • Survey for Little Fire Ants
    • Classroom Visits
    • Presentations & Workshops

ʻŌhiʻa’s genetic diversity may contribute to disease resistance

Posted on November 23, 2020 by Lissa Strohecker

The natural genetic variation in ʻōhiʻa may translate to some resistance to Rapid ʻŌhiʻa Death. To both preserve the genetic diversity present in ʻōhiʻa and test for disease resistance, there are seed banks established throughout Hawaiʻi. — Masako Cordray photo

ʻŌhiʻa is both a pioneer – the first to grow on new lava– and a protector—hosting and sustaining birds, insects, and plants throughout Hawaiʻi. ʻŌhiʻa is at home in nearly every terrestrial ecosystem in the islands, from the wettest rainforests to the leeward slopes of dryland forests. Its flowers range from cool yellow to fiery red. Leaves can be small, curled and fuzzy, and snuggled together along the stem, or stretched, shiny and drooping. The tree may crawl, bonsai-like on mountain tops, or assume a stately, spreading pose above the rainforest. The plant’s scientific name, Metrosideros polymorpha, only begins to reflect the “many morphs” of ʻōhiʻa. ʻŌhiʻa exhibits so much variation that taxonomists have classified the tree into different species and varieties, seven of which occur on Maui.

While ʻōhiʻa is amazingly adaptable, the reliance of so much native biota on its existence exposes a vulnerability. Without ʻōhiʻa, our forests – dryland to mesic to the rainforest – and the species within them are in peril. Rapid ʻŌhiʻa Death, the fungal disease that has killed ʻōhiʻa across 135,000 acres of Hawaiʻi Island, and counting, makes this abundantly clear. The discovery of this pathogen on Kauaʻi in 2018 further underscores the risk, even though it is not yet known from the other islands.  

“The goal is to preserve the genetic diversity of ʻōhiʻa naturally present in the landscape,” says Dr. Marian Chau.

Ripe ʻōhiʻa seeds being grown on the Hawaiian Islands for the preservation of the native species. —

One source of hope is that ʻōhiʻa’s high degree of genetic diversity could contain the key to disease resistance. Across the state, foresters and conservation groups are partnering on a project to collect and store seeds in ʻōhiʻa seed banks. “The goal is to preserve the genetic diversity of ʻōhiʻa naturally present in the landscape,” says Dr. Marian Chau, seed lab manager at Lyon Arboretum on Oʻahu. “The seeds can be used for current research on potential genetic resistance to Rapid ʻŌhiʻa Death, and for future restoration.” ʻŌhiʻa produces plentiful seed that can be stored for up to 18 years. To preserve and represent this variation, the seed collection campaign has a lofty goal of obtaining seeds from 10,000 different trees of fourteen different species.

Each island is divided into seed zones and collectors record the zone where they harvest seeds. If there is no representation from a particular zone, Chau and her colleagues reach out to those working in the area. The Laukahi Hawaiʻi Plant Conservation Network, a voluntary alliance focused on protecting Hawaiʻi’s rare plant species, created the seed zones and manages the data.

Throughout Hawaiʻi, partnerships have been made to collect wild-grown ohia seeds. There are currently more than four million seeds in the collection — Laukahi Network photo

With support from the Hawaiʻi Tourism Authority, Chau has traveled across the state offering free training on how to properly collect ʻōhiʻa seeds. Her workshops cover identifying the variety; determining if seeds are ripe; cleaning and packaging ʻōhiʻa for storage; and recording and submitting collection data. The trainings are empowering community participants to help stop the devastation of Rapid ʻŌhiʻa Death. The workshops are open to the public, but only naturally-occurring ʻōhiʻa are candidates for seed banking, not landscape-planted trees. To collect seeds from ʻōhiʻa in the wild, landowner permission and necessary permits for state or federal land are required.

To guard against inadvertent destruction (e.g., from a tropical storm), the seedbanks are scattered throughout the state, with redundant banks in different locations. Hawaiʻi Island seeds are stored on that island due to concerns about the accidental spread of the disease.

You can find more information about seed banking efforts online at http://laukahi.org/ohia/ including ʻōhiʻa identification information, seed collection guidelines, data collection, and needs. Learn more about Lyon Arboretum’s Seed Conservation Laboratory at http://manoa.hawaii.edu/lyonarboretum/seed-lab/. Stay up to date on Rapid ʻŌhiʻa Death at rapdiohiadeath.org and through the Rapid ʻŌhiʻa Death Facebook Page.

Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy, and quality of life.

This article was originally published in the Maui News on June 9th, 2019 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Read more Kiaʻi Moku articles

Filed Under: Home Slider, Kia'i Moku Column Tagged With: 2019, biodiversity, rapid ohia death

Coqui frogs negatively affect the environment in more ways than one

Posted on June 18, 2020 by Lissa Strohecker

Coqui have the perfect environment in Hawaiʻi, one that lacks the predators – lizards, tarantulas, and snakes- found in their native Puerto Rico. They reach densities two to three times greater in Hawaiʻi than in Puerto Rico, the densest population of land-living amphibian known anywhere. — Maui Invasive Species Committee photo.

In the dark, Darrel Aquino turns off the pump engine – the silence is a stark contrast to the noise of the gasoline motor, and before that, the piercing calls of the coqui frogs that met Aquino and his crew from the Maui Invasive Species Committee when they arrived hours earlier. They work together to pack up, rolling up fire hose by the light of headlamps before heading back to the baseyard. They’ll be back out tomorrow, and the night after, but in a different area of Haʻikū, as they work to stop the spread of the coqui frog.

From dusk to dawn males call for mates, “Co-qui, co-qui.” The first note, “Co,” lets their competition (other male frogs) know they are there, and the “qui” is for the girls. As loud as a lawnmower or leaf blower, the calls drown out the sounds of a night in Hawaiʻi: crickets, the night breeze rustling leaves, waves breaking along the coast. 

But while the ear-splitting call of this tiny tree frog is what they are famous for, problems with the coqui frog goes beyond noise. Like us, these invasive frogs from Puerto Rico also find our island habitat and climate to be paradise. Coqui in Hawaiʻi reach population densities greater than any terrestrial amphibian species elsewhere in the world. At over 20,000 frogs per acre in an environment that evolved without frogs, there is bound to be an impact.   

“Coqui in Hawaiʻi reach population densities greater than any terrestrial amphibian species elsewhere in the world. At over 20,000 frogs per acre in an environment that evolved without frogs, there is bound to be an impact.”

Dr. Karen Beard, a professor at Utah State University, and her students have studied coqui frogs in the Islands for more than a decade. The interactions between invasive species from different parts of the world coming together in a new environment can be hard to predict, but her research is finding that the presence of coqui in Hawaiʻi tends to benefit other introduced species – from invasive plants to non-native birds to mongoose.

Coqui frogs alter the way nutrients cycle in the ecosystem. The frogs feed on insects, mainly ants, roly-polies, cockroaches, and earthworms, but not mosquitos. What goes in must come out and hundreds of thousands of invasive frogs contribute additional nitrogen and phosphorus to the soil. Though these additions help plants grow, the increase really only benefits introduced plants. The flora native to the Hawaiian Islands is adapted for nutrient-poor volcanic soils, so by increasing soil nutrients, the coqui frogs modify conditions to favor invasive plants such as strawberry guava (native to Brazil).

Coqui frogs also bolster populations of non-native birds. Beard found that populations of some introduced songbirds, including common myna, Chinese hwamei, and red-billed leiothrix (all from Asia), are higher where coqui frogs are present. This is likely due to changes in the insect community when coqui are present (more excrement and frog bodies means more flies) as well as birds consuming the eggs in addition to juvenile and adult coqui.

Mongoose (from India) may also benefit from coqui. Beard’s graduate student Shane Hill looked at rat and mongoose densities where coqui are present compared to where they are absent and found greater mongoose abundance with coqui present. Mongoose are the main scavengers of coqui frogs, which may provide a novel food source. Hill also concluded that increased numbers of non-native birds or coqui-induced habitat changes could favor mongoose.

An invasive mongoose thriving off the abundance of the coqui frog population while increasing the likelihood of predation to other native Hawaiian species. — photo courtesy of Karen Beard

Hill’s study also showed fewer rats where coqui are present, more so for Pacific rats, which den underground as opposed to the more arboreal black rats. Hill and Beard suggest lower rat abundance could result from competition with coqui for insects or increased predation by mongoose. While the relationships are complex, one thing is clear: more mongoose is not good for ground-nesting birds, such as the ʻuaʻu kani (wedge-tailed shearwater) or endangered ʻuaʻu (Hawaiian petrel), and coqui could indirectly contribute to a decline in these birds.

Humans may adapt to the noise of coqui but the environment may be forever changed by their presence; interactions among these invasive frogs and other introduced pests tend to compound the impacts.  It’s critical to do what is possible to keep these invasive pests out of the native-dominated areas of Hawaiʻi and sensitive bird habitat.

You can help stop the spread of coqui on Maui. If you have coqui, volunteer in your neighborhood to reduce coqui and remove frog-friendly habitat. If you don’t have coqui in your area, stay alert to any nighttime “Co-qui” calls and report it to MISC at 573-6472.

Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy, and quality of life.

This article was originally published in the Maui News on February 10th, 2019 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Read more Kiaʻi Moku articles.

Filed Under: Home Slider, In the field, Invasive Animals, Kia'i Moku Column, MISC Target Species, Report a Pest Tagged With: 2019, coqui, coqui impacts on environment

Measuring the impacts of invasive plants in Hawai’i’s watersheds

Posted on June 5, 2020 by Lissa Strohecker

University of Hawai’i professor and researcher Tom Giambelluca is looking to better understand how invasive plants, like strawberry guava on the right, disrupt the water collection function of a native rain forest like that on the left.

In Hawaiʻi, the supply of fresh plentiful water depends on the forest capturing moisture from fog drip and rain, and then move it to streams and aquifers. Scientists and resource managers know that invasive plants disrupt the capacity of a native ecosystem to collect water. In Hawaiʻi, invasive species are the greatest threat to the function of native ecosystems.

But there are many unanswered questions about how and to what degree invasive plants affect the water capture in Hawaiʻi. Water capture, depends on both rainfall and cloud or fog drip, water then moves through the forest and soil to streams and underground reservoirs (aquifers). Some water is lost through evaporation and transpiration – the movement of water from roots through the leaves and into the atmosphere.

Like straws, plants pull water out of the ground and release it into the air. Differences in both the physical structure and growth characteristics contribute to different rates of transpiration between native and invasive species. Tom Giambelluca is looking closely at those differences. Giambelluca is the director of the Water Resources Research Center and a Professor in the Department of Geography and Environment at the University of Hawaiʻi at Mānoa. He has spent much of his career looking at the impacts of invasive species on water resources in Hawaiʻi. His latest research attempts to tease out and quantify how invasive species increase the loss of water back into the atmosphere.

 “One of the reasons invasive plants take over might be that they grow faster,” he says. “Faster growing plants tend to use more water” and over the long run, as invasive plants take over the native dominated forest, these differences in transpiration rates could have significant impacts on the cycle of water through the environment and the availability of water for human use.

To quantify these impacts, Giambelluca has relied on an experimental model of setting up monitoring equipment in paired sites where forest dominated by native species is growing immediately adjacent to stands of invasive plants. This site selection eliminates differences that may be caused by soil types and weather patterns in geographically separate locations. Weather can vary dramatically within small distance in Hawaiʻi. He then looks at the differences in transpiration by setting up tall towers filled with monitoring equipment and using measurements of water flow moving up the stems of sample trees.

But suitable study sites are hard to find – and funding additionally limits the number of sites he can potentially set up. With only a limited number of sites, he can’t accurately predict the impacts of invasive species may have on transpiration rates across the landscape.

So, Giambelluca is developing an experimental model wherein he can evaluate sites based on data that can be collected in a single day, therefore enabling his team to gain a better understanding of how individual differences in plant transpiration rates can impact water capture throughout Hawaiʻi. And he’s focusing primarily on leaves.

“Leaves are where the action is,” explains Giambelluca. “It’s where the plants control the uptake of carbon dioxide and release of water vapor.”


He takes a handful of measurements including the leaf area index (the surface area of all leaves over a given area), and leaf gas exchange rates of different plant species. The more leaves in an area, the higher the transpiration rates. Invasive – dominated forest tends to have a higher leaf area index (i.e,. more leaves). Plant species transpire at different rates.  After he has enough data to be statistically significant, he can then combine that with distribution maps of plant species across Hawaiʻi, and better assess the impacts invasive species have on the amount of water lost through transpiration.

While still in the proposal stage with results a few years in the future, the potential outcomes from this research could help inform the decisions resource managers and funders face in setting priorities both for which species should be controlled as well as which areas are more sensitive to the impacts of invasion. In the meantime, enjoy a fresh glass of water brought to you by a native forest nearby.

For more information on Giambelluca’s research, check out his lab page at https://sites.google.com/a/hawaii.edu/ecohydrology_lab/

Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy and quality of life.

Originally published in the Maui News on November 9th, 2019.

Filed Under: Home Slider, Kia'i Moku Column, Watershed impacts Tagged With: 2019, invasive plants impact watersheds, Strawberry guava, transpiration rates of invasive plants

Just the act of observing can help us and our island home

Posted on April 9, 2020 by Lissa Strohecker

The Hawaiian language reflects a close tie to the land. Connecting to nature can benefit both the health of the environment and the quality of life. — BRYAN BERKOWITZ / Maui Invasive Species Committee photo.

I ka nānā no ka ‘ike.
By observing, one learns.

‘Ōlelo No’eau #1186- Mary Kawena Pukui

The Hawaiian language includes over 200 words for rain with a subset of names specific to a place. Hawaiian rain names recognize that what falls from the sky can be delicate (lilinoe, kili, uaoa); windblown (lelehuna); showery (ua nuālu); cold (kili hau or ua ‘awa); or rainbow-hued (uakoko). The reddish ulalena rain falls on Haʻikū. Uakea mists Hāna. Winds can also be place-specific: the ʻakipohe wind nips Waiheʻe; the ʻimihau wind brings storms to Lahaina.

The language of Hawaiʻi reflects the deep relationship between people and nature. The original naturalists and resource stewards of Hawaiʻi – Hawaiians–have a keen understanding of their surroundings, from the terrain and weather to local plants and animals. This understanding is also reflected in place names. Hāiʻimaile translates to the blanket of the maile vine. Kanaio recalls the shrubby naio trees that once dominated the forests of the area.

Understanding of place was essential to the survival of the first island residents. And yet today, with the distractions of modern life, it’s easy to forget that a relationship to nature is still essential: both for our well-being and the health of the environment.

Recent research on the Japanese practice of shirin-yoku or “forest bathing” has demonstrated the health benefits of intentional time in nature. Observing the natural world elevates immune response and lowers blood pressure and stress levels.  Forest bathing began in Japan in the mid-1980s and is now an integral preventative health activity there. Interest has spread to the United States, with forest bathing clubs forming in urban areas. Forest bathing is not hiking, nor does it have to take place in a forest. Practitioners go out into nature to experience, with all senses, their surroundings –the range of colors, the scents and sounds in the air, the feeling of sun or breeze on their skin.

Essentially, tuning into nature as a naturalist would.

Forest and Kim Starr, early detection specialists with the University of Hawaiʻi, are self-taught botanists, entomologists, and ornithologists. They often conduct inventories of a defined area, identifying the species of plants, birds, animals, spiders, snails, and insects present.

The view from Hana’ula looking towards ʻIao Valley. Pu’u Lio is the summit between Kapilau and Kalapaokailio ridge.

“When we are out there, we’re using all our senses,” says Kim. Cued in to bird calls while simultaneously scanning for the next plant species to add to the list, the Starrs are intently focusing on their surroundings. They often return to the same place repeatedly, documenting changes. Their efforts help resource managers find invasive species before they are widespread and causing harm in the environment.

What the Starrs do – tune into the world around them and note the changes – can be done by anyone. Like forest bathing and Hawaiian practice it simply requires paying attention to our surroundings and being curious. Training is not necessary, but repetition enhances the experience, both in better understanding what belongs and does not belong in the area and achieving the health-related benefits.

Spend time outside, it’s good for your health and Hawaiʻi.

Learn more about the names of the winds and rains near your home. This list of weather names from The Ka’imi loa o ka hihi Project is a good place to start. Discover a forest bathing practice of your own—find resources and information at www.natureandforesttherapy.org. As you deepen your connection with the natural world, you can help protect Hawaiʻi from newly arrived pests; report changes in your surrounding from potentially invasive species to www.643PEST.org.

Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy, and quality of life.

This article was originally published in the Maui News on January 13th, 2019 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Read more Kiaʻi Moku articles.

Filed Under: Kia'i Moku Column Tagged With: 2019, early detection, Hawaii naturalist, Hawaiian place names, sense of place

Perils of pampas on West Maui Mountains

Posted on November 18, 2019 by Lissa Strohecker

Steve Perlman examining invasive pampas grass in Kauaʻula Valley. — MISC file photo

With plumes that bring to mind ostrich feathers, pampas grass first became popular in the Victorian era. Fluffy seed heads decorated the most fashionable hats, homes, even carriages. Interest surged again in the mid-1960s and the plant became a fixture in some yards and golf courses on Maui.

Today, pampas is taking over Instagram feeds: the plumes are used to add a Bohemian/Southwestern flavor to wedding bouquets, centerpieces, and home décor. But here on Maui, this ornamental grass is associated with a different trend: loss of habitat for threatened and endangered species and destruction of the watershed.

“But here on Maui, this ornamental grass is associated with a different trend: loss of habitat for threatened and endangered species and destruction of the watershed.”

Pampas can grow on nearly vertical slopes, displacing native plants that support populations of threatened and endangered animals and disrupting watershed function. With seeds that can travel 20 miles in the wind, ornamental plantings can infest far away forests. — MISC file photo

Pampas is a clumping bunchgrass native to South America. The leaves are razor-sharp, dying back each year but leaving dry foliage that accumulates and can fuel wildfires. The decorative plume is the seed-head and a single plant can spread millions of tiny seeds on the wind – in some cases, as far as 20 miles. Seeds germinate readily on bare soil, but with enough moisture, the invader finds footholds in patches of moss or tree bark. The plant competes with native vegetation and could replace habitat and food resources used by native birds and in doing so disrupting the layered structure of the rainforest so important for aquifer recharge.  

This grass knows no limits – it has been found growing from sea-level to the rim of Haleakalā Crater at 9000 feet. Water, or lack thereof, doesn’t seem to be a key determinant for where pampas lives. It will (and does) grow in the wettest rainforests and on the driest hillsides, often emerging in rain-drenched bogs and wind-scoured cinder slopes.

Pampas grass has been a target for eradication on Maui since the mid-1990s when staff from Haleakalā National Park started finding feathery plumes in the crater. MISC has been working to stop pampas since the inception of the program. Through continued control efforts, the East Maui population has been in steady decline but without consistent support and control efforts, progress could stall.

MISC employee scoping out pampas. Invasive plants don’t always grow in easily accessible areas. The slopes of West Maui are so steep that efforts to remove plants like pampas grass necessitate the use of helicopters. — MISC file photo

The West Maui pampas population has always presented challenges. Much of the difficulty lies in the rugged terrain and weather, limiting access for much of the year. On East Maui, crews can access much of the known pampas infestation by timing helicopter flights early in the day and camping and hiking to access plants from the ground, but the slopes of the West Maui Mountains are more vertical than anywhere else in Maui, affording few camping sites and making ground access difficult or impossible. Pampas, on the other hand, thrives on the bare soil of the erosion-prone slopes. When that happens, our crews depend on helicopters to seek out and remove the invader.

Thanks to funding from the National Fish and Wildlife Foundation, MISC crews have been scouring the cliff faces of West Maui over the last year. They are looking for pampas plumes and the tell-tale growth pattern of the plant before it goes into flower. If they find the plant, they record the location by on a GPS and then return by helicopter but this time loaded down with an external tank and 80’ long line and weighted sprayer attached. This allows the pilot and crew to hold hover over the plant and remotely trigger a tiny spray of herbicide directly to the grass below.

Despite nearly constant rescheduling of flights due to weather or a need for the helicopters to go fight a brush fire, crews have flown over 15,000 acres on West Maui from 2017 to the summer of 2019. This coverage has led to the detection and removal of nearly 1,900 pampas plants from the mountain slopes– a huge leap forward in the effort to stop this invader from taking over prime habitat for native birds, plants, and invertebrates.

You can help. First, become familiar with what pampas grass looks like (mauiinvasive.org/pampas/). Second, never plant pampas grass or import it for décor or floral arrangements. The Division of Forestry and Wildlife has designated pampas as one of Hawaiʻis most invasive horticultural plants. Finally, report any pampas grass you find. You can report it to MISC: 573-6472, miscpr@hawaii.edu, or online at 643PEST.org

Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy, and quality of life.

This article was originally published in the Maui News on September 14th, 2019 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Read more Kiaʻi Moku articles.

Filed Under: Kia'i Moku Column Tagged With: 2019, invasive ornamental grasses, pampas grass

Invasive longhorned beetle bores into fruit trees, threatening crops

Posted on August 28, 2019 by Lissa Strohecker

Large beetles have begun to spread across Puna but have not yet been detected on other islands. They pose a threat to fruit growers on the island and throughout Hawaii. Native to Queensland, the Acalolepta aesthetica, longhorned beetles are dimpled and fuzzy on their abdomens. — Photo courtesy of Big Island Invasive Species Committee.

In 2009, a resident of Orchidland subdivision in Puna on Hawaiʻi Island found a strange beetle with extremely long antennae on the screen door. This report marked the first detection of a new species of longhorned beetle, Acalolepta aesthetica, in Hawaiʻi and the United States. Lacking an official common name, the beetle is called the Queensland longhorn beetle, reflecting its native home in Australia.

Despite survey efforts by the Hawaiʻi Department of Agriculture, the beetle wasn’t detected again for years, but that first incursion wasn’t a one-off and its population continued to grow. Four years later it was seen again. Sightings increased as the beetles spread across Puna. Over the last 3 months, the Big Island Invasive Species Committee has received over a dozen reports.  

The arrival of this new insect has officials with the Hawaiʻi Department of Agriculture (HDOA) concerned. According to HDOA entomologist Darcy Oishi, the Queensland longhorned beetle could significantly damage citrus and other trees.  The larvae tunnel through living wood creating big galleries, similar to termites, but on a much bigger scale. Oishi says, “They make these giant weeping wounds in branches or the trunk of a tree. The damage can cause dieback in a limb or the death of a tree.”

“They make these giant weeping wounds in branches or the trunk of a tree. The damage can cause dieback in a limb or the death of a tree,” says Oishi.

Not much known about this beetle, perhaps because it’s not a pest elsewhere. Its arrival in Hawaiʻi marks the first time this beetle has acted invasively with potential impacts only now being realized. The list of trees damaged by beetle larvae continues to grow. It’s been found tunneling through lemons, limes and other citrus; Polynesian-introduced trees such as ulu (breadfruit) and kukui; favorite food crops like cacao (chocolate) and possibly avocado; and introduced species such as gunpowder trees and sago palm. As the current world expert on the beetle, the Hawaiʻi Department of Agriculture has not identified any natural enemies in Hawaiʻi nor any effective controls methods.

Complicating research on control options is the presence of native longhorned beetles in our state. Important both as wood decomposers and food for native birds, our Cerambycid beetles are one of the many native insects that show amazing rates of adaptive radiation. From what entomologist estimate was three distinct arrivals, over 120 species evolved. One of the largest native insects in Hawaiʻi is a Cerambycid beetle; measuring 2 inches from ­tip to tail with sweeping antennae as long as its body, Megopis reflexa is closest in appearance to the invasive Acalolepta aesthetica.

The new wood-boring pest is not yet known from Maui or any of the other Hawaiian Islands, but farmers and residents can take steps to prevent its arrival. The best way to keep it from moving interisland is to not bring green woody material between islands, particularly if the vegetation shows signs of damage, such as weeping wounds where a beetle may have laid its eggs and larvae entered the tree.

The larvae of Acalolepta aesthetica, a longhorned beetle from Australia, leaves large weeping holes in tree trunks of food crops like citrus and cacao. — Photo courtesy of Hawaii Department of Agriculture.

Be alert to sightings of the beetle, often attracted to house lights at night. The adult measures from 2-4.5cm (3/4-1 ¾ inches) in length. The antennae on the male are twice as long as the body – giving rise the moniker “longhorned.”  Antennae on the female are shorter. On either side of the thorax (the body part behind the head) are two thorn-like spines. The abdomen is dimpled and looks as though covered in peach fuzz. In contrast, the native Megopis beetle has ridges running down the abdomen, giving it a striped appearance.

There is a native longhorned beetle – Megopis reflexa – that is nearly the same size as the invasive Queensland longhorned beetle. Look for stripes running the length of the body. –Photo courtesy of Ross Kamimoto

Oishi also suggests looking for wounding on trees.  The beetle larvae can be even larger than the adults and as they leave the tree to mature, they leave behind large holes, up to 1.25 cm (1/2 inch) in diameter, as big around as a pinky.  Other indications are sawdust-like frass being pushed out of holes on the trunk, girdling on trunk, sap oozing from where the adult laid eggs, and branch dieback and drop. Find more details and the official pest advisory on the HDOA website: http://hdoa.hawaii.gov/pi/ppc/new-pest-advisories/.

On Maui, report any suspected sightings. Collect the beetle and contain it in a secure container. Take clear digital photos of the beetle and record the location, type of plant or tree, date, and how you found it. If you see damage on a tree, take photos. Use an object (coin or ruler) for reference.  Email the photos and the information to HDOA.PPC@HAWAII.GOV or report it online through 643PEST.org.

 Lissa Strohecker is the public relations and education specialist for the Maui Invasive Species Committee. She holds a biological sciences degree from Montana State University. Kia’i Moku, “Guarding the Island,” is prepared by the Maui Invasive Species Committee to provide information on protecting the island from invasive plants and animals that can threaten the island’s environment, economy, and quality of life.

This article was originally published on August 10th, 2018 as part of the Kiaʻi Moku Column for the Maui News.

Read more Kiaʻi Moku articles.

Filed Under: Kia'i Moku Column Tagged With: 2019, Queensland longhorn beetle

Stay Informed

Enter your email address to subscribe to this blog and receive new posts by email.

Like us on Facebook

Get Involved

  • Donate
  • Classroom Visits
  • Meetings Minutes
  • Pest Flyers

Sign up for MISC Updates

* = required field

Contact Us

Maui Invasive Species Committee (MISC)
Office: (808) 573-6472
Mailing Address:
PO Box 983, Makawao, HI 96768

Manager: Adam Radford
E-mail:miscmgr@hawaii.edu

PR/Outreach: Serena Fukushima

E-mail:miscpr@hawaii.edu

Pest Hotline: 808-643-PEST
Report a Pest Online

© 2021 Maui Invasive Species Committee (MISC) • Sitemap • Log in