MISC Target Species — Maui Invasive Species Committee (MISC)

Why All the Talk About Eradication?

Posted on August 17, 2017 by MISC

Test any material coming from an area infested with little fire ants. Preventing the spread of pests to new areas and finding infestations early is critical to achieving eradication. Photo by Masako Cordray

Life in paradise inevitably means dealing with invasive species in some form. From termites to rats, centipedes to garden weeds, there is an unending onslaught of pests we all deal with. Efforts to control them usually buy a temporary respite; we known and expect these pests will return.

Eradication, removing every last reproducing individual (or seed, in the case of plants) is the gold standard of invasive species management. In theory, eradication is achievable for any pest species, given enough time and money. In reality, time and money are in short supply. Deciding to eradicate a species is a significant undertaking, typically only possible when the target population level is low and accessible.

It took 80 years to eradicate feral goats from the island of Kahoʻolawe but today the island is recovering.

Goats once ran rampant on Kahoʻolawe. Introduced to the island in 1793, a gift to Chief Kahekili of Maui from Captain Vancouver, these hearty hooved beasts quickly took over, limited only by food availability. They devoured the vegetation on the island, threatening native species and exacerbating erosion. Starting in 1910, a host of assorted land managers, including ranchers, the military, and the state government battled goats on Kahoʻolawe. Over a period of 80 years goats were hunted aggressively—but always a few remained, too difficult to find. When control would cease, goat populations would explode again.

The last goat was finally removed in 1993 that goats were truly eradicated from the island. Those last few goats were the hardest to find, yet tracking down the holdouts was critical to the island’s vegetation recovery. As was the case on Kahoʻolawe, persistence is often a key ingredient of successful eradication efforts.

“It’s easy to kill 99% …. It’s the last 1% that makes it tricky,”

Not just large invaders can be eradicated—little fire ants, for example, are eradicable. These miniscule ants have something in common with the goats that once riddled Kahoʻolawe: removing the last few is the most challenging yet most important part of the job.

Until Hawaii Ant Lab arrived, attempts at eradicating the tiny ground and tree-dwelling little fire ant had failed. Getting a bait to the queen is part of the challenge, one met by their research and expertise. Photo by Masako Cordray

“It’s easy to kill 99% of the ants. It’s the last 1% that makes it tricky,” says Cas Vanderwoude, manager of the Hawaiʻi Ant Lab. His organization provides the expertise behind the efforts to eradicate little fire ants from Maui. And, as with any attempt to truly eradicate an invasive species, most of the work lies in finding the last few. “Surveys are essential to understanding where the ants are, how effective the treatment is, and if the population is eradicated.” Currently, MISC and the Hawaiʻi Ant Lab anticipate that infested properties will be monitored indefinitely to ensure the little fire ant has been eradicated.

The fact that these tiny invaders also live in trees adds to the challenge. Historically, treatment of the little fire ant relied on granule pesticides developed for fire ants in general. These granules could only be scattered on the ground and did nothing to control the colonies of ants living in trees. In Hawaiʻi, worker ants find enough food in trees, relying on sap sucking insects and other food sources, never needing to forage on the ground. Without workers carrying bait back to the queen in the nest, the colony will survive, reproduce, and reinvade, as the goats of Kahoʻolawe did time and time again. Fortunately, the Hawaiʻi Ant Lab has developed techniques for controlling little fire ant on the ground and in the trees.

Little fire ants seen on a taro leaf for scale. These tiny terrors have huge impacts. Photo by Masako Cordray

On Maui there are only a handful of little fire ant populations: Nāhiku, Kapalua, Huelo, and Waiheʻe. Though eradicating these infestations will be a challenge, complete removal of the little fire ant from Maui is the goal thanks to the expertise of the Hawaiʻi Ant Lab.

Eradication is time-consuming and expensive, though the price is negligible when compared to the never-ending cost of suppressing these pests so we can continue to enjoy life in Hawaiʻi as we know it. Economists estimate that the cost of damage from little fire ants on Hawaiʻi Island will exceed $140 million if current trends continue.

Eradication is costly, but it is an investment in the future. You can help to keep little fire ants at bay by ensuring you do not have any present on your property. Survey your yard for the little fire ant. Quarantine and test potted plants, mulch, and soil before distributing it on your property. Find testing information online at stoptheant.org or littlefireants.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.

Originally published in the Maui News on January 6th, 2017 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Why All the Talk About Eradication?

Life in paradise inevitably means dealing with invasive species in some form. From termites to rats, centipedes to garden weeds, ...
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Fire! Little Fire Ants in Hawaii

Little fire ants are spreading throughout the state. First introduced to Puna in 1999, and shortly thereafter to Kaua’i, these ...
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Invasive species can sting aloha

Aunty Penny Martin is a lei-maker on Molokaʻi. She was talking story one day with a friend visiting from Hawaiʻi ...
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LFA – Insidious invaders that you can stop

Ginger Johnson bought a hapu‘u fern late in 2013 to plant alongside others in her yard. But when she heard ...
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The little fire ant-bad news for food crops

The little fire ant, Wasmannia auropunctata, is a pest with a deservedly nasty reputation. Alone, this wee ant is neither ...
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Moving? Leave the pests behind

Ask anyone who has moved lately - it’s a daunting task. Every move, whether across town, across the state, or ...
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An entire colony of the little fire ant can fit inside a macadamia nut shell. Photo by Hawaii Department of Agriculture

Residents urged to report unusual stinging fire ants

An infestation of the much-dreaded little fire ant (LFA), Wasmannia auropunctata, was discovered on a farm in Waihee, Maui, in ...
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Fire! Little Fire Ants in Hawaii

Posted on February 17, 2016 by MISC

Little fire ants are spreading throughout the state.

First introduced to Puna in 1999, and shortly thereafter to Kaua’i, these ants are one of the worst invasive species imaginable in Hawai’i. They invade houses, gardens, and forests. The ants are also arboreal; they swarm up plants and trees. When disturbed, they drop off, falling onto people and animals. Unsuspecting victims are left with painful stings.

Until recently, little fire ants were limited primarily to Hawai’i Island but as infestations have grown there, so has inevitability of their spread.

In January of 2014 little fire ants were detected on Oʻahu, leading to a multi-agency response resulting in containment and eradication. These tiny pests have hitchhiked to Maui and Lānaʻi as well. Meanwhile, Hawaiʻi Island residents are faced with creating sanctuaries amidst a sea of stinging ants.

This 30 minute documentary examines the spread of the little fire ant and the people who work to address one of the most significant invasive species problems confronting the Islands.

Funding support for this video was provided in part by the Maui Invasive Species Committee and the Hawaiʻi Invasive Species Council.

A Haʻiku gulch full of suprises

Posted on July 24, 2015 by MISC

The prickly seed ponds on this climbing vine led to a concernd Ha'iku resident reporting it to MISC as a potential invader. Turns out it is a native plant, Mucuna sloanei. Photo by Hank Oppenheimer

The prickly seed pods on this climbing vine led to a concerned Ha’iku resident reporting it to MISC as a potential invader. Turns out it is a native plant, Mucuna sloanei. Photo by Hank Oppenheimer

“Anything that bristly has got to be invasive,” said the Haʻiku resident who reported a vine that she found in the gulch on her family property. She called the Maui Invasive Species Committee (MISC) when neither she nor her relatives could identify the strange climber with seedpods covered in fiberglass-like hairs. No one in the family had noticed it before and they had worked or played in the gulch since small-kid times. She collected a specimen, prickly seedpods and all, and brought it into the MISC office.

Though bristly, it turned out not to be an invasive species after all. The unusual creeper was a native plant once widespread in low elevations on Maui and other Hawaiian Islands. Commonly known as seabean, botanists call it Mucuna sloanei.

Mucuna comes in two varieties: sloanei, indigenous to Hawaiʻi; and persericea, endemic to windward East Maui and found nowhere else in the world. There are only a few of the persericea plants left. Because of the rarity of the persericea variety, and the damage caused by pigs and cattle to its habitat, the vine was recently listed as endangered by the U.S Fish & Wildlife Service. The possibility that it could be thriving in a Haʻiku gulch, only a stone’s throw from the Haʻiku Marketplace, was therefore pretty exciting. But it takes an expert to know the difference between the two varieties and Hank Oppenheimer fits the bill.

Oppenheimer is the Maui Nui Coordinator for the Plant Extinction Prevention Program (PEPP), a Pacific Cooperative Studies Unit project that works to protect the most rare and threatened plants in Hawaiʻi. Throughout the state, a handful of people like Oppenheimer and technician Keahi Bustamente hike deep into remote forests, scaling cliffs and doing whatever they can to prevent the rarest species’ extinction. This includes collecting seeds from rare Hawaiian plants, propagating them in greenhouses, and then outplanting the precious plants in protected habitat.

For plants, garnering listing as a PEPP species of interest is a mixed blessing; it means there are less than 50 individuals left in the wild. Oppenheimer is investigating the distribution of persericea to determine if it should be included with the other 236 PEPP targets.

Finding the native Mucuna sloanei was a pleasant surprise. Photo by Hank Oppenheimer

Oppenheimer and Bustamente headed to the Ha’iku gulch. The vine turned out to be the more common sloanei, but Oppenheimer was still excited. “It was really interesting to see Mucuna in a place like that,” he said. Most of the habitat for Mucuna has been turned into pasture, farmland, or long ago taken over by invasive plants.

But as the team was leaving the gulch, they made a troubling discovery. Bustamente noticed an unusual plant with massive 2-3 foot long leaves, purple on the underside. He knew it instantly as miconia. This notorious pest and MISC target was certainly out of place; miconia is primarily between Keʻanae and Hāna. The discovery marks the westernmost naturally occurring plant in recent history.

So when the Haʻiku resident reported what she thought was an invasive vine, she actually helped uncover a relatively rare native species as well as one of the most invasive plants in Hawaiʻi. A great example of the more you look, the more you find.

Can you spot the miconia plant? The characteristic large leaves with purple undersides cued botanists into this plant’s presence in a Ha’iku Gulch. MISC file photo

To learn more about the Plant Extinction Prevention Program, visit the website www.pepphi.org. And if you think you may have Mucuna on your property, contact Hank Oppenheimer at henryo@hawaii.edu. If you would like help identifying an unusual plant, native or not, you can find a number of resources available online, including the Flikr site “Hawaii Plant ID,” curated by some of the state’s best botanists, or you can call MISC at 573-6472, particularly if you think you’ve found miconia.

Originally published in the Maui News, April 12th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Invasive species can sting aloha

Posted on April 15, 2015 by MISC

Photo courtesy of Forest and Kim Starr.

Aunty Penny Martin is a lei-maker on Molokaʻi. She was talking story one day with a friend visiting from Hawaiʻi Island, and the conversation turned as it often does, to lei-making. The friend had a lime-green hydrangea growing in her yard and offered to bring her some. “As a lei maker, the hydrangea are the best for making lei po‘o (lei for the head),” said Aunty Penny. “I was really excited to see.”

At their next meeting, her friend had brought the beautiful flowers from Hawaiʻi Island. “I was overcome by the hydrangea,” she said. “I was ooh-in and ahh-ing,” Then she noticed her friend must have picked them on the go, bagging them before leaving to go to the airport so they would be fresh. While the lei-maker was touched by the gesture, the sight of the freshly bagged hydrangea triggered a thought. “It was like an epiphany—I’m thinking fire ants, coqui. I really wanted it….my hands were just itching to make that lei.”

The lime-green hydrangea ended up double bagged to contain any pests and buried at the Molokaʻi landfill. “It would have been easy to stop thinking responsibly,” said Aunty Penny.

As every malahini (newcomer) soon learns, the expansive aloha spirit also celebrates the bounty

The aloha spirit celebrates the bounty of the land, but invasive species threaten to change the practice of bringing gifts from our homes.

of the land. Sharing in that bounty goes beyond good manners–it’s culture. Bringing gifts from your home, be they avocados or citrus, flowers or orchids, even cream puffs or manapua from a local bakery, is part of our way of life.

But as devastating pests like little fire ants become established on some islands and not others, our culture may change. “That kind of sharing and exchanging—pretty soon not going to be the norm, ‘cause you’re going to be worried about things,” says Aunty Penny.

Concerns about invasive species affect even the most traditional of cultural practices. Last summer, a group of students on Big Island helped place lei on every known burial site at Kalaupapa on Molokaʻi to remember those who lived and died there. The lei brought from the Big Island were made of ti leaves, chosen in part because they could withstand freezing to kill any little fire ants.

Invasive species have affected cultural practices in other ways: apple snails munch taro throughout much of the state, scale insects on hala can ruin the leaves for weavers in East Maui, and mites threaten the coconut groves planted for King Kamehameha V on Molokaʻi.

Lei-makers often share material between islands. Increasing concerns about transporting pests is beginning to hamper that practice. Photo courtesy of Maui Nui Botanical Garden.

“I grew up with the tradition of bringing lei from island to island,” says Aunty Penny. “It just crushes me that now I have to think about fire ants and coqui.” Hawaiʻi residents don’t have to stop sharing plants and flowers with friends, but taking a few minutes to check that the gifts are free of unintentional hitchhikers will help keep the natural environment and native culture intact. “I loved that hydrangea,” says Aunty Penny, “but I love Molokaʻi more.”

Originally published in the Maui News, March 8th, 2015 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

LFA – Insidious invaders that you can stop

Posted on August 7, 2014 by MISC

Ginger Johnson bought a hapu‘u fern late in 2013 to plant alongside others in her yard.

MISC employee Molly Wirth surveys for LFA in response to a Maui residents concern about little fire ant moving in hapuu. No LFA were found. MISC file photo

But when she heard the news in early January that inspectors found a new species of fire ant hitchhiking from the Big Island to Maui in hapu‘u , she thought of the hapu‘u she had just brought home. What if the ants had infested her yard? “I was very concerned. I went and looked at it and didn’t see anything.” Johnson left the hapu‘u in the shade of a tree, uncertain about what to do.

“I called a friend of mine who happened to be a biologist. He advised that I do the peanut butter and chopstick test.” The simple test, placing a peanut-butter smeared chopstick near material that may carry little fire ant, will attract many ants, including Wasmannia auropunctata, the little fire ant (LFA). Johnson tested but did not find any ants that resembled LFA, which are tiny (as long as a penny is thick) and uniformly light red in color. She was still concerned and called the Maui Invasive Species Committee (MISC) for further assistance.

Crews from MISC arrived, bagged the hapu‘u to contain any ants, and took it to the Hawai‘i Department of Agriculture (HDOA) where entomologists examined it for LFA. No suspect ants were found. But because the hapu‘u had been at Johnson’s house for a little while, MISC workers surveyed her property. They’ll return several times to ensure LFA weren’t introduced. This new pest is so damaging, it’s worth the extra effort to prevent it from becoming established on Maui.

Little fire ants can be hard to find when first introduced. Workers may not be foraging far from the queen, and even if several colonies are present, these miniscule insects are very hard to detect. Bait (like the peanut-butter-smeared chopstick) must be placed every two feet or closer. By the time the ants are stinging people or blinding pets, the population may have been present for months or years.

Little fire ants on the large end of a chopstick. Photo courtesy of the Hawaii Department of Agriculture.

These opportunistic ants don’t build mounds; rather they find shelter in leaf litter, under rocks, or in loose tree bark. Little fire ants are insidious invaders. They don’t announce their presence by swarming feet and legs; instead, they sting when they are trapped against skin or in clothing. Establishing nests in trees and amongst ground cover, LFA can reach densities of 20,000 workers per meter, or a whopping 155 ants in a square inch. At that level, painful encounters become unavoidable.

So: if it’s small, call. MISC will survey your property, using peanut butter to attract ants. Alternatively you can submit a sample to MISC. Expert taxonomists review all ants collected. If they suspect little fire ants, they’ll take the sample to HODA for confirmation.

Little fire ants are not known to be established on Maui, Lāna‘i or Moloka‘i; though small infestations have been detected and controlled on Maui and Lāna‘i. Resources exist to stop this pest in its tracks. An interagency team made up of the Hawai‘i Department of Agriculture, Hawai‘i Ant Lab, and Maui Invasive Species Committee will respond to any new infestation in Maui County.

Inspectors at the Kahului airport destroy any little-fire-ant-infested shipments they find, but some might slip through. No organization has the resources to survey all of the places or pathways LFA could travel. If you have brought any soil, potted plants, or vehicles from off-island in the last year, take time to test for LFA. Waiting until you are stung is too late.

“I’m tremendously careful now,” says Johnson. “Someone just told me the other day they got a magnolia tree from the Big Island. My first thought was: how well did you test it?”

To learn more about the little fire ant, including detailed instructions for how to survey, visit the Hawai‘i Ant Lab’s website at littlefireants.com. The HDOA site at hdoa.hawaii.gov/pi/main/lfainfo/ has updated information on spread. If you suspect you may have LFA, please don’t try to treat them yourself– contact MISC at 573-6472 or the Maui branch of HDOA at 872-2848. “The issue is so frightening,” says Johnson. “I’m born and raised here, so I’ve seen many things change. The only time to deal with something like this is before it’s a disaster.”

By Lissa Fox Strohecker. Originally published in the Maui News, May 11th, 2014 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

The little fire ant-bad news for food crops

Posted on June 30, 2014 by MISC

Liitle fire ant colony inside a macadamia nut

Little fire ants have many queens in the colony, and by moving a queen the population spreads to new areas. If you live in an area infested with little fire ant, don’t bring the pest to your new home. Photo courtesy of Hawaii Department of Agriculture.

The little fire ant, Wasmannia auropunctata, is a pest with a deservedly nasty reputation. Alone, this wee ant is neither aggressive nor impressive, but with her sisters, living in a network of colonies stretching from tree-top to ground, she has a dramatic impact. Once established, little fire ants are more than a pest, they will put the kibosh on agriculture. Little fire ants have already shut down fruit orchards in the Hilo area and their establishment threatens agriculture throughout the state.

Little fire ants do not compete between colonies; rather, they cooperate, blanketing the ground and trees and outcompeting other ant species for food and resources. Other insects and animals may also be pushed out and end up abandoning highly-infested areas to the little fire ant.

As little fire ants find homes in bananas, citrus, rambutan, and coffee trees, farmers faced with new difficulties in harvesting their crops. Because the ants don’t hold on well to branches, scads of tree-dwelling ants rain down on workers become trapped in their clothing, and sting in self-defense.

fungus on coffee infested with little fire ants

Stinging ants raining down upon harvesters is enough of an obstacle for coffee infested with little fire ant, but additionally, yields are reduced because little fire ants protect aphids that support plant disease, like this fungus. Photo by Cas Vanderwoude

In the Galapagos, little fire ants have made harvesting coffee one of the most difficult ways to earn a living; coffee harvesters now command a higher wage than other agricultural workers to compensate them for the aggravation. Increased costs affect farm profitability; in several areas of the Galapagos, coffee plantations lay abandoned because of the little fire ant. In Kona, the famed coffee-growing area, and elsewhere in the state, most coffee is harvested by hand. The spread of LFA into coffee plantations will be a huge blow to an industry already struggling to address the coffee borer beetle, another invasive pest that threatens the coffee industry as it reduces yields.

Little fire ants threaten more than just coffee. In Brazil and Cameroon, little fire ants infest cacao farms. In Puerto Rico, Florida and New Caledonia, little fire ants have overrun citrus

Cacao and other tree crops are particularly susceptible to little fire ant infestations. Photo used by permission from Cas Vanderwoude.

groves and in some areas practically blanket the ground.

The ants are causing havoc with other types of agriculture as well. Little fire ants cause blindness in animals and livestock, poultry, and pets in infested areas have a much higher incidence of blindness than do animals without LFA.

Controlling these ants is extremely difficult, especially for tree crops, as few pesticides are registered for use in trees and the bait must stick to branches long enough for the ants to find it. Existing control techniques rely on traditional pesticides; an effective organic method has yet to be developed.

As with any invasive species, preventing spread and establishment are the most cost-effective approaches. Eradication is possible only if the population is small. Once established, these ants may be forever. Little fire ants are widespread on the eastern side of Hawaii Island and beyond eradication in that area, but further spread throughout the state can be prevented. Help protect agriculture on Maui, as well as your own quality of life. Support efforts to prevent their movement between islands and quarantine and check any plants or soil you bring on to your property for little fire ants. Learn more at www.lfa-hawaii.org and www.littlefireants.com.

By Lissa Fox Strohecker. Originally published in the Maui News, May 13th, 2012 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Moving? Leave the pests behind

Posted on June 25, 2014 by MISC

Moving interisland, or even within the island, comes with the risk of bringing invasive species along MISC file photo

Ask anyone who has moved lately – it’s a daunting task. Every move, whether across town, across the state, or across the world involves choices: what to take and what to leave behind. Depending on where you are moving to and from, some of the “take it or toss it” decisions can have a major impact on the environment. Yes, you want to take your prized orchids, but what if they are carrying a pest you don’t want at your new home? Whether you are moving to the mainland or merely interisland, you should take steps not to bring trouble with you.

Hawai‘i is particularly susceptible to introductions of foreign species and each Hawaiian island is battling its own unique set of pests—plants, insects, or animals that are not found on the other islands. For example, fireweed is ubiquitous on the slopes of Haleakalā on Maui, but it’s on target for eradication on Moloka‘i and Kaua‘i. Red-vented bulbuls, a notorious agricultural pest common on O‘ahu, haven’t yet invaded Maui. How could one of these noisy birds find its way into your luggage? You’d be surprised.

Red-vented bulbuls are cavity nesters. While they most often nest in tree trunks, these opportunists have been known to squeeze into the ends of curtain rods or the tops of ceiling fans. These pestiferous birds are suspected of making it to the Marshall Islands as stowaways in a cargo container.

Less conspicuous than bulbuls are coqui frogs. These tiny hoppers can easily travel with potted plants. Gardening and yard

A notorious hitchiker, the coqui frog, hides in plants and cars. This frog goes through the tadpole stage inside the egg, meaning it's even easier to spread the frog. MISC file photo

A notorious hitchhiker, the coqui frog, hides in plants and cars. This frog goes through the tadpole stage inside the egg, meaning it’s even easier to spread the frog. MISC file photo

supplies like hoses, weed mats, and empty pots are perfect habitat for this noisy amphibian, so check twice before packing these things if coqui are already your neighborhood. If you do choose to bring plants or gardening gear, make sure they are clean and frog-free. Contact your local Invasive Species Committee for treatment information.

One of the tiniest yet most damaging interisland hitchhikers is the stinging little fire ant, now widespread in parts of the Big Island. An infested property can have millions of ants; one square foot can have over 1,800 worker ants with three to seven queens. It only takes one queen and fewer than a dozen workers to start a new colony. The ants can set up shop anywhere – a bed, macadamia nut shells, a computer or golf bag, so it’s easy to accidentally transfer a satellite colony to a new location. If you are moving from a little-fire-ant zone be sure you’re not packing a pest. Your family, pets, and new neighbors will appreciate it!

Shipping your car? Automobiles have been the source of new coqui populations. The small frogs find car bumpers and undercarriages the perfect place to amplify their calls. On a windy day, little fire ants rain down from trees into the beds of pickups and crevices of cars, coming along for the ride to find new habitat to invade. If you live in an infested area, check your car and consult the experts for how to rid these species from your belongings. That way you can move without compromising quiet nights and peaceful time outdoors.

Are your pets moving with you? If you have a cat or dog, just check with the airline, but if your pet is on the “exotic” range of the spectrum—birds, chinchillas, rats, rabbits, guinea pigs, and even lizards—it should be cleared with the Hawai‘i Department of Agriculture. The Jackson’s chameleon, often kept as a pet on Maui, is not established on Lānaāi, Moloka‘i, or Kaua‘i. It’s an invasive species that can harm endangered Hawaiian snails and other native invertebrates if it becomes established in wild areas.

When you are researching a big move, take a few minutes to investigate how to avoid spreading unwanted species to your new home. If you are moving interisland, the island-based Invasive Species Committees are good sources of information. Call the local office or find out online what they are working to control. Any plant material should be inspected by the Department of Agriculture before going interisland. Find the contact for your local Plant Quarantine Office here: http://hdoa.hawaii.gov/pi/plant-quarantine-contacts/. Bring the memories – but leave the pests behind.

By Lissa Fox Strohecker. Originally published in the Maui News, March 9th, 2014 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee

Blessed Milk Thistle

(Silybum marianum)

Family: Asteraceae

Blessed milk thistle, or Silybum marianum, isn’t so holy when it forms prickly, invasive thickets. Conservationists quick to eradicate it from Maui pastures. Photo courtesy of Maui Invasive Species Committee

This thistle is native to the Mediterranean regions of Europe and North Africa. Milk thistle thrives in high fertility soils and moist areas such as riverbeds and pastures. It’s a common weed in the Western U.S. and is a noxious weed in Washington and Oregon.

Description:

Robust, fast growing thistle that can grow to 2-6 feet tall
It has purple flowers (1.5″ to 2″ long) that are surrounded by long spines.
Its shiny green leaves have distinctive white veins, which give them a mottled appearance
The wavy leaf margin is covered in spiny edges

Harm:

Milk thistle produces copious amounts of seeds (6,000 per plant) and has large leaves which will shade out other plants.
It also contains high levels of nitrate which are poisonous to ruminant animals such as cattle and sheep. Seeds remain viable in the soil for up to 9 years and the plant thrives in disturbance, making eradication difficult.
Thistle seeds have tiny tufts of hair (like dandelion seeds) which aid in wind dispersal. It can be spread accidentally in cattle feed, water, mud, vehicles, machinery, erosion and by animals.

In Hawaii:

Maui – Only known from a naturalized population in the Makawao area of Maui. MISC is working to eradicate the populations. Rarely cultivated as an ornamental, blessed milk thistle is more commonly grown for its medicinal properties. If you see this plant anywhere on Maui, please report it.

Don’t confuse with:

Mexican poppy, also known as prickly poppy, (Argemone mexicana), is a widespread weed on Maui with similar green and white mottled leaves. It can be differentiated by its yellow poppy-like flowers (2.5” wide), and skinnier leaves. It produces a bright yellow sap when the leaves or stems are broken.
Bull thistle, (Cirsium vulgare), is a widespread weed on Maui that also has a purple flower and similar growth form. However, bull thistle has uniformly green leaves covered with small bumps.

For more information, see:

Blessed Milk Thistle article for MISC Kia’i Moku column

Mullein

(Verbascum thapsus)

Family: Scrophulariaceae

Considered very invasive and is on the Hawaii State Noxious Weed List.
The Division of Forestry and Wildlife of the Hawaii Department of Land and Natural Resources has designated this species as one of Hawaii’s Most Invasive Horticultural Plants.

Description:

Herbaceous biennial that reaches up to 10′ tall by its second year.
Large oval-shaped leaves range in size from 3-20″ long and 1-5.5″ wide. Covered in dense woolly hairs.
Sends up a flower stalk in the second year reaching 10′ tall, clusters of small yellow flowers grow in a random fashion along the stalk.
Native to Europe, mullein is naturalized in temperate ares of the world and has been intentionally cultivated for its medical properties.

Harm:

Quickly colonizes disturbed areas and out-competes native vegetation.
Produces numerous seeds that may remain dormant for over 100 years.
Drought-tolerant and able to withstand cold, mullein could invade native alpine ecosystem in Hawaii in places like Haleakala

In Hawaii:

Hawaii Island – Common on leeward uplands 3,940-9,840 ft of Mauna Loa, Mauna Kea, and Hualalai. It occurs also occasionally occurs in areas outside these zones, including windward Mauna Loa and some coastal and arid western sites.
Maui – First discovered in 1986 at over 9,000′ on Haleakala. It has since been found culitvated at several locations in Kula, all known locations are under active control and surveillance.
Not known from Kauai, Oahu, Molokai, Lanai, and Kahooolawe.

Little Fire Ant

Little Fire Ant (Wasmannia auropunctata)

Family: Formicidae

Since the discovery of Wasmannia auropunctata on the Hawaiʻi Island in 1999, the Hawai’i Department of Agriculture (HDOA) worked closely with the local invasive species committees (including MISC), as well as the United States Fish and Wildlife Service to prevent the further spread of this ant species. The Hawaiʻi Ant Lab, a project of the Pacific Cooperative Studies Unit, is also working diligently to mitigate the threats and prevent the inter-island and intra-island spread of existing invasive ant species, including the little fire ant.

Description:

This ant is orange-red to light brown in color, all workers are 1.5 mm in length (half the size of a sesame seed, or as long as a penny is thick, about 1/16 “)
Slow-moving, easily dislodged from leaves, plants, and trees
Prefers moist conditions, forming colonies on the ground AND in trees
Native to Central and South America, LFA were accidentally introduced as hitchhikers on imported plants

Harm:

Delivers a painful sting when disturbed. Welts can last for weeks
Infests agricultural fields and farms, where they damage crops and sting workers
Promotes plant pests such as aphids, white flies and scale insects, which secrete plant sap that the ants eat. In turn, the ants protect these insects from natural predators and parasites.
Easily blown out of trees, stinging when they get are caught in hair or clothing.
Infests homes, beds, furniture and food
Has been linked to corneal clouding and blindness in pets
In the Galapagos, LFA attack tortoise hatchlings and sting the eyes of adult tortoises
Infest bee hives, preying on the larvae and eventually destroy the hive.
Large infestations are difficult and expensive to control

On Maui:

First detected on Maui in October of 2009 in Waiheʻe. Thanks in part to the early detection of the infestation, an extremely cooperative landowner, and the recently formed Hawaiʻi Ant Lab, the 1/3 acre infestation was eradicated.
December 2013: a Maui resident discovers LFA in hapuʻu logs purchased from a local garden shop. Trace-back efforts by HDOA uncover infested material shipped several places in the state.
June 2014: a MISC employee surveying for LFA discovers an extremely small population of LFA in a South Maui hotel.
September 2014: MISC field crews working to control miconia find a 20+ acre infestation in a densely vegetated area near Nahiku.
January 2015: a Maui resident reports stinging ants to MISC. Delimitation surveys reveal a 5-acre infestation in Huelo and ants moved to a single location in Haʻikū.
Early detection and prevention are essential and the public is urged to report unusual ants on Maui to MISC at 573-6472 or HDOA at 643-PEST.
All known infestations have been or are currently being controlled. MISC partners with HDOA and Hawaiʻi Ant Lab in detection and control efforts, as well as public outreach activities to raise awareness about LFA.
MISC’s management goal for little fire ant is island-wide detection and eradication.

Pest Alerts and Publications:

LFA Brochure
“Invasion: Little Fire Ants in Hawai’i,” A documentary by Maui Invasive Species Committee
Little fire ant updates from Hawaii Invasive Species Council

Why All the Talk About Eradication?

“It’s easy to kill 99% …. It’s the last 1% that makes it tricky,”

Why All the Talk About Eradication?

Fire! Little Fire Ants in Hawaii

Invasive species can sting aloha

LFA – Insidious invaders that you can stop

The little fire ant-bad news for food crops

Moving? Leave the pests behind

Residents urged to report unusual stinging fire ants

Fire! Little Fire Ants in Hawaii

A Haʻiku gulch full of suprises

Invasive species can sting aloha

LFA – Insidious invaders that you can stop

The little fire ant-bad news for food crops

Moving? Leave the pests behind

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Harm:

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Mullein

(Verbascum thapsus)

Description:

Harm:

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Little Fire Ant

Little Fire Ant (Wasmannia auropunctata)

Description:

Harm:

On Maui:

Pest Alerts and Publications:

For more information, see:

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