Solutions — Maui Invasive Species Committee (MISC)

MISC Coqui Catching and Spraying Tips

Posted on September 16, 2024 by MISC

Even when our coqui crew is fully staffed, success depends on collective kuleana: communities working in their yards so MISC can focus on outliers and containment.

Things you will need:

Garden, backpack sprayer, or spray bottle Request a Backpack Sprayer
Citric acid powder Request Citric from MISC.
Water
Gloves
Long sleeves/Pants
Closed-toe shoes

1. Locate Frogs

Spraying is most effective at night time as you can get a quick confirmation if they are not calling post-spray. They are often in-between leaves of bananas, ti plants, palms, and/or bromeliads. They cannot hang upside down. If it is in an area where you can hand-capture it, put it in a plastic bag once captured and dispose of it accordingly. Learn from the pros. Watch our short coqui catching video.

2. Mix and prep

Many sprayers work for coquis, below are recommendations on which one you might want to use depending on population size.

1-5 Coquis: Zep size cleaning spray bottle, 1-2 gallon sprayer pump

5-20 Coquis: 1-2 gallon sprayer pump, backpack sprayer

20+ Coquis: Backpack sprayer, 55-gallon sprayer and 100-gallon truck bed sprayer Request a Truckbed Sprayer

Mix powdered citric with water at the ratios that we provide when you get the citric. Mixing in a 5 gallon bucket before putting the solution in the sprayer can work well for larger quantities. Only 2 milliliters of solution need to touch the frog for successful control.

3. Spray

Spray directly where you are hearing the frog. If you cannot see it, use a 10ft buffer to help your chances. They are sensitive to light and movement. Keep your flashlight off until you know you are close and staying quiet can help keep the frog calling. If it does stop calling, you can whistle their “Ko-Kee” tune to encourage them.

If you can’t whistle, this link of a coqui recording works well to get them calling when they fall silent. Some nights the coquis will not be chirping for reasons unknown even though they are still there as surveys the night before proved, and whistling or playing the video can help with that. Spraying every six weeks works best to disrupt the breeding cycle.

4. Cleanup:

No matter what type of sprayer you use, it is best to empty the citric out and store in another container, rinse out the sprayer with water, and spray out that water through the nozzle. The citric can become corrosive over time and ruin the sprayer lines and nozzles.

Detection of Coconut Rhinoceros Beetle on Maui Highlights Importance of Community Involvement in Pest Prevention

Posted on September 21, 2023 by Lissa Strohecker

*An abbreviated list of best management practices for Maui.*

The Coordinating Group on Alien Pest Species (CGAPS), program staff from the Hawaiʻi Invasive Species Council (HISC), and the five Invasive Species Committees (ISCs) in Hawaiʻi are urging vigilance by contractors and landowners to prevent the accidental spread of invasive species.

To support these efforts, CGAPS, HISC support staff, and the ISCs have compiled a list of best management practices (BMPs) for coconut rhinoceros beetle (CRB), little fire ants, and other species.

This appeal comes at a time when the urgent need to address impacts from the Maui fires may increase the introduction of infested materials from off-island, and CRB has been detected on both Maui and Kauaʻi.

The proposed reissuance of an emergency quarantine measure, Plant Quarantine Interim Rule 22-1, which restricts the movement of mulch and other potential CRB host materials from Oʻahu, is an important step, but by itself will not be adequate to the spread of this harmful pest. Contractors and individuals need to be sure that pests are not unwittingly moved in palm trees, green waste, mulch, loose or bagged compost, bagged soils, and similar items.

Throughout the state, the continued spread of pests poses significant risks:

Kauaʻi: The recent arrival of the coconut rhinoceros beetle pest to Kaua’i (detected May 31, 2023) highlights the threat posed by the movement of infested material. A decade of research on controlling the pest could lead to eradication on Kaua’i, but limiting the human-vectored spread is critical to achieving this goal.
O’ahu: Continued human-vectored spread will exacerbate the challenges in addressing this pest.
Maui County: with the increased volume of material moved to and around Maui to help with fire recovery efforts (including mulch and imported coconut coir, mulch, or greenwaste for use in erosion control sock filler), mulch and compost for restoring burn scars, and plants for restoration, there’s an increased risk of introducing invasive species.
Hawai’i Island: To date, CRB have not been detected on Hawai’i Island. Should they arrive, they would likely spread quickly, given the low population density and plentiful habitat that could lead to challenges in detecting and eradicating the pest.

The BMPs highlight practices to prevent the spread of coconut rhinoceros beetles, but also provide general guidelines for little fire ants, coqui frogs, two-lined spittle bug, and other invasive species.

For restoration projects, the BMPs provide guidance on fire risk assessments and non-invasive characteristics for selecting plants.

For more information:

List of Best Management Practices: https://dlnr.hawaii.gov/hisc/files/2023/09/BMPs-for-Invasive-Species-Prevention-091223.pdf
Christy Martin, Coordinating Group on Alien Pest Species, christym@rocketmail.com
Coconut Rhinoceros Beetle Response: (808) 679-5244, info@crbhawaii.org
Island-based Invasive Species Committees: https://www.hawaiiinvasivespecies.org/
Pacific Fire Exchange: Melissa Chimera, melissa@hawaiiwildfire.org

Natural enemies could tame invasive Himalayan ginger

Posted on June 5, 2018 by Lissa Strohecker

Though not invasive in India where it is native, Himalayan ginger can completely transform a Hawaiian rainforest like it has in this section at 4,000-foot elevation above Haiku. Inset: Ginger fruits are spread long distance by birds and rats. FOREST and KIM STARR photo

The subtropical rainforests in the foothills of the Himalayan Mountains are amazingly diverse. In sections of India and Nepal, the forests are similar to Hawaiian rainforests in both temperature and rainfall-but the flora and fauna are radically different: this is the land of elephants and red pandas; 600 species of butterflies live here and over 400 species of orchids. But amongst the exotic plants there is one

The fruit of Himalayan ginger is a tasty treat for non-native birds, but this means the seeds are spread throughout the forest. Photo courtesy of Forest and Kim Starr.

that might be familiar to residents of Hawai’i-a yellow-flowered ginger that covers vast sections of Hawaiian rainforests.

Himalayan ginger, Hedychium gardnerianum, is native to the Himalayan foothills. There, it evolved over millennia supporting a diversity of species: the sweet nectar is a food for the long-tongued butterflies of the region and the plant lives in harmony with the species that surround it. Yellow flower stalks dot the landscape amongst hundreds of other orchids, gingers, ferns, and trees.

But in Hawai’i, Himalayan ginger dominates the landscape-growing fast and paving its way into the forest in an unrelenting march.

“Himalayan ginger displaces critical native vegetation layers, limits canopy tree recruitment, and hogs water resources in their massive rhizomes (roots). As it takes over and forms monotypic stands, it negatively impacts native flora and fauna, including Hawai’i’s unique arthropod complex and the Hawaiian honeycreepers,” says Alison Cohan, director of the Maui Nui Forest Program with The Nature Conservancy (TNC).

Introduced as an ornamental, Himalayan ginger escaped backyards and began invading rainforests of East Maui in the mid 1950’s. With seeds dispersed far and wide by birds and rats, the weedy plant spreads by leaps and bounds into the forest. Today, much of the mid-elevation rainforest of East Maui is a patchwork of native forest and alien ginger. But there is a lot left to protect: many ginger-free areas remain, including most of West Maui.

Ginger is a formidable foe and removing the plant is no simple task. Roots pave the forest floor like asphalt and every part of the rhizome must be removed. Bagged rhizomes take years to decay and if there is the slightest hole in the bag, hardy shoots emerge. If using herbicide, every portion of the root has to be treated. Plants on steep slopes and cliffs are inaccessible and impossible to remove until the weight of the water-logged roots causes entire sections to collapse in a landslide.

Why would ginger be a pest in one place but not another?

Djami Djeddour, weed biocontrol scientist with the Centre for Agriculture and Bioscience International, inspects a lone Himalayan ginger plant in India while searching for insects and fungi that live on the plant where it is native. These insects may be responsible for keeping the plant in check. DJAMI DJEDDOUR photo

The answer to that question is on the minds of resource managers in Hawai’i as well as New Zealand, Australia, and South Africa where the plant is invasive. With funding from organizations like TNC and the Hawai’i Invasive Species Council, research scientists traveled to India and collected insects and fungi that live on Himalayan ginger hoping to discover what keeps the fast-growing herb in balance there. An effective natural enemy could be a game changer for Hawai’i.

An effective natural enemy wouldn’t eliminate the plant, just bring it into harmony with the surrounding environment, much like it is in India and Nepal.

One of the most promising insects is a Cloropid fly that lives only on Himalayan ginger. The larvae live inside the stem stunting the growth and reducing flower production. Ginger natural enemies may be ready for release in New Zealand soon, promising progress for Hawai’i.

“The Nature Conservancy had been doing ginger work in Waikamoi for over 30 years, systematically conducting ginger control—containing the core population at the western edge of Waikamoi and eradicating outliers in native forest,” explains Cohan. Crews with Haleakala National Park work on the flowering pest in Kīpahulu Valley but the plant is widespread and thrives unchecked in wet places throughout the state.

There are ways you can help. Consider what you call the plant: though known for years as kāhili ginger, a pest destroying the rainforest does not deserve a moniker reminiscent of Hawaiian royalty much less one that might suggest that it belongs here. Perhaps call it toilet-brush ginger, as suggested by Pat Bily of TNC after years of removing it. Do not plant Himalayan ginger in your yard and remove it from your property before it spreads. Finally, participate in The Nature Conservancy’s quarterly volunteer trips removing ginger from Waikamoi Preserve. Contact hike_waikamoi@tnc.org if interested.

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 April 8th, 2018 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

What if there were no mosquitoes in Hawaiʻi?

Posted on March 18, 2016 by Lissa Strohecker

The Aedes aegypti mosquito is the primary vector of dengue worldwide. This species is not widespread in Hawaii. Photo by James Gathany,CDC.

The news is abuzz with mosquitoes these days; outbreaks of dengue fever on Hawaiʻi Island have us all a little more nervous when the high-pitched whine of a tiny pest reaches our ear. Mosquito-vectored viruses like Zika and chikungunya are on the horizon. Health officials in both South America and Hawaiʻi Island are scrambling to find ways to reduce mosquito populations and protect human health. Scientists are busy making nearly daily advances in the lab as well. All of the energy focused on removing these pests raises the question: how would the total removal of mosquitoes alter ecosystems?

There are over 3,500 species of mosquitoes in the world, of which only a few hundred bite. Mosquitoes and their larvae are food for fish, bats, birds, and dragonflies. Male mosquitoes don’t suck blood, they daintily sip nectar. In return, they help to pollinate some aquatic plants. But despite their service as prey and pollinator, many scientists think ecosystems would recover just fine if mosquitoes were gone–other insects could fill that niche, and we’d have one less vector for disease. Good news globally, but it only gets better for Hawaiʻi.

The Culex mosquito, larvae shown here, is the mosquito responsible for spreading avian malaria between introduced and native birds. Photo by James Gathany, CDC.

In Hawaiʻi, mosquitoes are food for native bats (ʻōpeʻapeʻa) and dragonflies (pinao). Would these species go hungry without this imported food source? Not in the least, explains Dennis Lapointe, an ecologist with the US Geological Survey who researches the ecological role of mosquitoes and birds in Hawaiʻi. “[Mosquitoes] are all non-native and everything that is native and endemic got along fine without them.” Some species of native damselfly larvae eat mosquito larvae, but they have other food sources.

The greatest ecological benefit would be to our native birds. Disease-spreading mosquitoes are a significant factor keeping iʻiwi,ʻ apapane, and other Hawaiian honeycreepers from flitting through the trees in your yard.

Aedes albopictus is widespread in Hawai’i and is a vector of Zika among other human diseases. Photo by James Gathany, CDC.

Mosquitoes first arrived in Hawaiʻi when sailors dumped a barrel of water containing larvae of the Culex mosquito into the wetlands that once surrounded Lahaina. The Culex mosquito became the vector that spread avian pox and malaria from non-native birds to Hawaiian forest birds, precipitating their decline. The native passerines lacked any resistance against these foreign diseases.

Today, our few remaining native forest birds are relegated to high-elevation refuges, protected by temperatures cool enough to keep mosquitos at bay. But protection could be short lived; current estimates of climate change indicate these refugia could disappear within 80-100 years.

If mosquitoes disappeared, so would the threat of avian malaria.

Currently, the fate of native birds is not foremost in our minds as human-health threats loom: the Aedes mosquitoes, which are also found in Hawaiʻi, are in the news now. A. albopictus, widespread throughout the Islands, is the primary carrier the Zika virus. A. aegypti, a mosquito found only in a few areas on Hawaiʻi Island, is the optimum carrier of dengue. Both Aedes species carry chikungunya. Both of these mosquitoes cause harm, with negligible environmental benefit.

Meanwhile, scientists are working on a tool to reduce mosquito populations without pesticides. Using genetic technology, a self-limiting gene is inserted into the DNA of male mosquitos. Reared in labs, the mosquitos are released to seek out and mate with females, but the self –limiting genes is passed along and their offspring die as

Mosquitoes breed in standing water, and removing breeding sites is one way to help reduce the density of mosquitoes. Photo by Mary Hollinger, NOAA.

larvae. The existing adults die off and are not replaced. Though years from being ready for release into the wild, scientists predict that these altered mosquitoes could be up to 99 percent effective in reducing mosquito populations, with no risk of developing resistance to pesticides. Each species of mosquito has to be targeted specifically, but Hawaiʻi has only a handful of invasive mosquitoes, all of which are non-native.

It’s something to think about: Hawaiʻi without mosquitoes, without the threat of dengue, Zika, or chikungunya. And, as an added benefit, Hawaiian forests with a few more native birds.

Until then, continue with mosquito-control efforts: dump standing water, treat bromeliads and other plants that hold water and mosquito larvae, and regularly apply repellent. These actions can help keep these blood-suckers at bay in your backyard.

Eliminate mosquito breeding sites: https://health.hawaii.gov/docd/files/2017/01/Eliminate-Mosquito-Breeding-Sites.pdf
Ecological role of mosquitoes: www.nature.com/news/2010/100721/full/466432a.html
Avian diseases in Hawaiʻi: https://mauiforestbirds.org/avian-disease/

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.

Written by Lissa Strohecker. Originally published in the Maui News on February 14th, 2016 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Make your yard less frog-friendly

Posted on June 23, 2015 by Lissa Strohecker

Coqui spend their days foraging in leaf litter for ants and other insects. They do not have a tadpole stage, and therefore do not need standing water to reproduce. Coqui lay eggs inside a rolled or folded up leaf, leaf litter, damp moss, or other shelter sites. By limiting the areas they can forage and nest, you will make your yard less appealing to coqui frogs and control efforts will be more effective

How to make your landscaping less coqui-friendly:

Limit and/or remove rubbish and green waste piles (chip it up), coqui like to hide in green waste. If you have coqui in your green waste pile, spray well with citric before moving
Don’t plant bromeliads or consider replacing them.
If you have cane grass, mow it.
Remove dead leaves on banana, ti, and other plants with large leaves
Thin out understory vegetation.

Find more tips for eliminating frog-friendly habitat here: http://www.ctahr.hawaii.edu/coqui/eliminate.asp

How to Mix Citric Acid for Coqui Control

Posted on June 23, 2015 by MISC

Follow all label directions. You can find a generic label for citric acid here: Citric Acid 25b label

Making your own citric solution:

MISC recommends mixing citric at a 16% solution or 1.28lb of anhydrous citric acid per gallon of water. The best method is to mix the solution by weight it but if you mix by volume use approximately 2 1/2 cups per gallon.
Citric dissolves in solution, but needs to be thoroughly agitated when mixing so that citric chunks will not clog your sprayer.
MISC can supply citric to community members. Call Rebecca Creighton, Coqui Field Coordinator at 808-633-6646 to acquire citric.

Storage:

To keep your gear (pumps, sprayers, etc.) in good shape, it is best to thoroughly rinse it with water. Metal pieces that have been touched by citric will start to corrode if not properly washed after each use.
It is best to store unmixed citric in a dry and shady area.

Common-sense caution:

Some plants are sensitive to citric acid, and can be burned if sprayed. You can reduce the damage to sensitive plants by rinsing off the spray within 15 minutes. Plants sensitive to citric acid solution
It is important to wear Personal Protective Equipment (PPE) when applying citric acid, as citric acid can irritate your eyes and skin. PPE includes shoes, long-sleeves, long pants, eye protection, and ear protection (if applicable).

Follow all label directions. You can find a generic label for citric acid here: Citric Acid 25b label

What’s that new black caterpillar?

Posted on July 22, 2014 by Lissa Strohecker

Secusio caterpillar eat fireweed and other invasive plants like Cape ivy, The Hawaii Department of Agriculture estimates it will take 8 caterpillars to kill one fireweed plant. Photo courtesy of HDOA.

A new fuzzy black caterpillar is starting to show up across Maui—a promising omen for cattlemen and conservationists alike. The caterpillar is the larva of the Secusio extensa moth, a biological control for firerweed released by the Hawai‘i Department of Agriculture (HDOA) to control fireweed in March of 2013.

Diana Crow, a horticulturalist with ‘Ulupalakua Ranch, has been helping to raise and release Secusio moths on Maui. “For a while I wasn’t seeing them at all. Then things changed when the rains came. I started seeing them around lights. That was the first indication they were reproducing in the wild.”

Impacts on fireweed aren’t likely to come immediately. Established in the islands since at least the 1980s, fireweed now infests an estimated 850,000 acres statewide. According to Rob Curtiss, an entomologist with HDOA, it takes an average of eight caterpillars to kill one fireweed plant. “What will probably happen is that the population [of Secusio] will continue to grow and reach epidemic proportions, then we will see them start to defoliate fireweed.”

Fireweed, Senecio madagascarensis, is a highly invasive weed, toxic to many animals that blankets pastures on Maui and Big Island. Photo courtesy of Forest and Kim Starr.

Secusio may be getting some help from another unwelcome pasture pest; the caterpillars are capable of living off Cape ivy, a noxious weed related to fireweed, and containing the same toxic properties. “It’s inedible for livestock,” says Crow of the ivy. “We don’t want it. Plus it’s a threat to higher elevation native forest.”

The moth’s broad appetite isn’t a surprise to state agriculture officials. Before Secusio was released, entomologists reared the caterpillars in captivity to test what plants they would eat. Confined in cages with 88 different kinds of plants (71 of which were related to fireweed), they found it only ate 6 different species, including Cape ivy, and all were closely related to fireweed. Any plant it caused significant damage on is considered a weed in Hawai‘i.

Also known as German ivy, Cape ivy is extremely invasive. Introduced at the turn of the century to Kona, Cape ivy escaped cultivation and now threatens watersheds and native forests on the Big Island and Maui. It spreads quickly and once established can be extremely tenacious. Pat Bily of The Nature Conservancy has found several small populations in the Waikamoi preserve. Using herbicide to control a smothering vine would damage native vegetation so Bily removes plants by hand. Every leaf, stem, and root have to be removed or the plant resprouts; eradicating a handful of small populations is taking Bily years.

“Any feeding on Cape ivy, even if it was low, is a benefit,” explains Rob Curtiss. “Cape ivy certainly can be an alternate host. If populations of fireweed go down and there are populations of Cape ivy in the area, they will sustain a larger population of Secusio and we’ll get a better impact on fireweed.”

How do you know if you have them? The larval stage of Secusio is a fuzzy black caterpillar

The Secusio moth is about the size of an almond with mottling on the wings. The moth is nocturnal; turning off lights in the evening will encourage the moth to return to fireweed plants to lay eggs. Photo courtesy of HDOA

with an orange head and sometimes orange feet. It ranges in size from 1/8^th inch when young to just over 1 inch before pupating into a moth. The moth is beige with brown mottling on the wings and about the size of an almond.

Are other plants on the menu for the Secusio moth? Seeing the caterpillar on other plants doesn’t mean the caterpillar is feeding on them. According to Curtiss, most feeding happens at night. The caterpillars often leave the host plants during the day to avoid potential predation.

People may also see them when the caterpillars are looking for a place to pupate, preferring a dark place like a garage or shed. “If you see them, leave them alone or take them outside,” advises Curtiss. The moths are nocturnal and attracted to light so leaving outside lights on all night may keep them close to houses rather than seeking out fireweed in adjacent pastures.

For more information about the Secusio moth, visit the HDOA website: http://hdoa.hawaii.gov/blog/news-releases/2013-news-releases/biocontrol-moths-released-on-maui-to-fight-invasive-fireweed/

By Lissa Fox Strohecker. Originally published in the Maui News, July 13th, 2014 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

Flower grower who detected little fire ant in December 2013 receives award

Posted on June 25, 2014 by Lissa Strohecker

Masako Cordray, 2014 Malama i ka Aina Award Winner

Farmer and flower grower Masako Cordray was the 2014 recipient of the Malama i ka Aina Award, presented Saturday June 14th in a ceremony at the Maui Association of Landscape Professionals’ Lawn and Garden Fair held at the Maui Mall.

The person nominating her said “Masako’s passion for land stewardship extends beyond the boundaries of the land she farms to the entire island.

On December 23, 2013, Cordray tested plant material she had recently purchased for little fire ants. After finding small orange ants on peanut-butter coated sticks she contacted MISC. Confirmation of the detection by the Hawaii Department of Agriculture set off a chain of events that resulted in the discovery of little fire ants at other garden shops and nurseries on Maui and Oahu and has sparked a statewide response “The 45 minutes she took to sample plant material has had immeasurable consequences. This is truly an example of the contributions one person can make” said MISC manager Teya Penniman.

Cordray has influenced invasive species prevention efforts for many years. She was part of grass roots efforts to incorporate an improved biosecurity facility when the Kahului airport was being expanded–actions that led to the completion of the Hawaii Department of Agriculture’s state of the art inspection facility completed in 2007. In addition to being a farmer, Cordray is an award-winning photographer and videographer and donated much of her time to helping educate the public about invasive species. She worked to create a film about miconia in 2006 and when little fire ants were discovered on Maui n 2009, she approached MISC about creating a film about this devastating species. A true artist, her attention to detail and uncompromising standards are evident in the quality of her work, both

(L-R) Allison Wright, MALP; Masako Cordray; Teya Penniman, MISC; Rob Parsons, County of Maui. MISC file photo

in her photographs and floral arrangements.

The Malama i ka Aina Award is presented annually to recognize an individual or business working within the landscape or agricultural community to keep invasive species out of Maui County. The award is sponsored by the Maui Association of Landscape Professionals (MALP), the County of Maui, and the Maui Invasive Species Committee (MISC).
This year’s award featured a glass sculpture of an endemic Hawaiian damselfly, or pinao, by local artist Jupiter Nielsen. Award presenters were MALP Vice-President Allison Wright, Maui County Environmental Coordinator Rob Parsons, and Penniman.

Press Release – 2014 MIKA awardee Masako Cordray_final

Roomba on the Reef–Native collector urchins on the prowl for invasive algae

Posted on January 21, 2014 by Lissa Strohecker Leave a Comment

A diver holds native collector urchin in his hand. Monitoring has shown these tiny urchins are successfully controlling invasive algae. Photo courtesy of Hawaii Department of Land and Natural Resources-Division of Aquatic Resources

Let’s say you are trying to remove tiny piece of invasive plant material from an area 8 miles long and almost 3 miles wide. If you miss any, it will take over again. And you are working under water.

This is the situation the Department of Land and Natural Resources-Division of Aquatic Resources (DAR) faces at Kāne‘ohe Bay on O‘ahu. An invasive algae, Kappaphycus spp., also known as smothering seaweed has overrun the reef causing a cascade of impacts. “They’re so aggressive they outcompete native limu [seaweed]; they grow so dense they kill coral and dominate habitat for tako [octopus] and small fish,” explains Jono Blodgett, aquatic species project leader with DAR.

First DAR tackled the alien algae with the Super Sucker, a giant vacuum mounted on a boat. Divers worked their way across the reef, sucking up the algae. Technicians would sort through it, tossing native limu back to colonize the reef, and bagging the invasive algae to give to local farmers to be used for compost. Unfortunately, gains were temporary–fragments of invasive algae left behind would regrow. DAR next called in native Hawaiian sea urchins with an appetite for invasive algae.

If the Super Sucker was a giant vacuum, native collector urchins (Tripneustes gratilla) are more like a Roomba, that small robotic vacuum that automatically cleans house floors. Once released, these spiny herbivores move across the reef munching algae as they find it. They would eat native limus as well, if the invasive algae hadn’t taken over all the natives.

Volunteers help rehome tank-raised native collector urchins to the reef in Kāne‘ohe Bay on O‘ahu. Photo courtesy of Hawaii Department of Land and Natural Resources-Division of Aquatic Resources

The first urchins were released by DAR in January of 2011 and they’ve proven their worth. Although this urchin is native to Hawai‘i, it wasn’t abundant enough on the reef to control the algae in Kāne‘ohe Bay. Their numbers used to be much greater in the Bay, but unknown reasons have caused their populations to decline. By elevating the urchin populations, resource managers are getting ahead of the invasive algae.

The urchins used are a native species, selected because they stay on the reef and munch algae day and night. Adult urchins are collected from the wild and bred in captivity. After juvenile urchins reach 15mm, typically within 5-6 months, they are sent to work: released in Kāne‘ohe Bay to settle out over the reef and eat to their hearts’ content. Currently 5000 urchins are released each month in Kāne‘oheBay.

Density numbers are still being analyzed, but initially, urchins are released at a density of two per square meter and once the algae are under control, one urchin per square meter keeps the reef maintained. With some patch reefs as large as 30,000 square meters, it will take a lot of urchins. “We’re hoping to double production by next year,” says Blodgett.

Native collector urchins dine happily on invasive alage in Kāne‘ohe Bay. Photo courtesy of Photo courtesy of Hawaii Department of Land and Natural Resources-Division of Aquatic Resources

Monitoring in Kāne‘ohe has shown that the collector urchins are effectively controlling invasive algae. Based on the success of the cleanup in Kāne‘oheBay, collector urchins could become invasive algae cleanup crews across the state. DAR has done trials to see if the urchins will control another alien alga: the gorilla ogo (Gracilaria salicornia) that plagues Waikīkī and much of Moloka‘i.

In the meantime, Blodgett advises leaving urchins and other herbivores alone and making sure dive and snorkel gear is free of any pieces of algae when you leave a site. Invasive algae spread through fragmentation, explains Blodgett, “Rinse gear before leaving a site.”

By Lissa Fox Strohecker. Originally published in the Maui News, December 8th, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.

The public health threat of invasive species-mosquitoes and dengue

Posted on August 23, 2013 by Lissa Strohecker Leave a Comment

Aedes aegypti is famous the world over for spreading dengue. This species is not established statewide, but it has shown up at the Honolulu International Airport five times since January of 2012. Photo by Muhammad Mahdi Karim

Back in 2001, several East Maui residents started reporting fever, body aches, and rashes. One of the people sickened had just traveled in French Polynesia during a dengue fever outbreak. The Department of Health eventually confirmed 20 cases of dengue fever in East Maui and a crew hired with funds allocated for environmental emergencies went to work removing mosquito habitat. What made this outbreak interesting was that it was spread by the tiger mosquito, Aedes albopictus, common in Hawai‘i.

“We may be the only place in the world to confirm [that] dengue could be spread by the albopictus mosquito. It’s not an efficient carrier of the disease,” explains Gary Gill, Deputy Director of the Environmental Health Administration with the Hawai‘i Department of Health. “In places where dengue is endemic [regularly occurring], it is the aegypti mosquito that is the carrier.”

The invasive mosquito, Aedes aegypti, is famous for spreading dengue. Neither the mosquito nor dengue is widespread in Hawai‘i. Both periodically appear, but luckily not at the same time. Though conditions are prime as Hawai‘i is a global hub for tourism and commerce..

Dengue outbreaks in Hawai‘i are rare and typically occur when someone travels to an infested area, returns to Hawai‘i and is bitten by a mosquito, as happened in 2001. According to Gill, immediate family members and neighbors are at risk, but the common tiger mosquitoes rarely eat from more than one source. The female mosquito finds a person (or animal), and, given the chance, feeds until her belly is about to burst.

In contrast, Aedes aegypti flit from person to person, taking a blood meal from multiple people and spreading any disease carried by the bloodsuckers. Aedes aegypti is not normally found on O‘ahu. “We have not, up until last year, identified any aegypti since the 1940s,” says Gill.

In January of 2012, a Department of Health entomologist collected a trap containing what was later identified as Aedes aegypti at the Honolulu International Airport. “We’ve found aegypti five times in the last year. Every indication is that this mosquito is either living and breeding at the airport, or it is regularly being reintroduced,” Gill says. Mosquitoes can survive in the cabin, cargo hold, or underbelly of an airplane coming from an infested area. Aedes aegypti are originally from Africa but have spread to tropical and sub-tropical regions of the world including Mexico, Asia, and Australia.

Dengue fever is a widespread subtropical disease that is continuously present in areas with established population of Aedes aegypti. This map shows the distribution of Aedes aegypti (blue) and Aedes aegypti and dengue fever (red). Image from Centers for Disease Control

From a public health standpoint having a thriving population of dengue-spreading mosquitoes at the airport is a worst case scenario according to Gill. “A person carrying the virus walks through the airport, and then it spreads to any number of people at the airport who will then take it to wherever they are going. A single population of aegypti could easily spread dengue throughout the state. A dengue-carrier mosquito would be a concern for people who come here as much as for people who live here.” If Aedes aegypti became established throughout Hawai‘i, it would set the stage for a consistent presence of dengue, like does in parts of Central and South America, India, Southeast Asia, and Africa.

Ongoing surveys for mosquitoes are the best way to ensure early detection of this species. The Department of Health continues to monitor mosquitoes at Honolulu International Airport, but surveys are limited to that airport and don’t include surrounding areas. Funding cuts in 2009 gutted the Department of Health. At one point 40 people worked on O‘ahu on environmental health but now only seven positions remain. Staff cuts throughout the state have left no capacity for mosquito monitoring elsewhere. “What’s at Kahului? We have no idea,” worries Gill.

The Department of Health is working with Hawai‘i’s Departments of Agriculture Transportation to explore options for mosquito surveys at airports and harbors statewide. They are working to reduce mosquito habitat at the airport, removing bromeliads and dark undergrowth and replacing it with less mosquito-friendly landscaping. Gill encourages homeowners to do the same, along with removing or changing water in outside open containers every week. For now it’s our best hope. Unless and until capacity is restored at the Department of Health, early detection of this devastating mosquito is up to the public.

By Lissa Fox Strohecker. Originally published in the Maui News, August 11, 2013 as part of the Kia‘i Moku Column from the Maui Invasive Species Committee.