Maui Invasive Species Committee (MISC)

Blessed Milk Thistle

(Silybum marianum)

Family: Asteraceae

Blessed milk thistle, or Silybum marianum, isn't so holy when it forms prickly, invasive thickets.

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:

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.

Banana Bunchy Top Virus

The plant on the left is infested with BBTV. Note how the new growth is bunched together, a symptom that gives the disease its name. Photo courtesy of Scott Nelson, UH-College of Tropical Agriculture and Human Resources

The plant on the left is infested with BBTV. Note how the new growth is bunched together, a symptom that gives the disease its name. Photo courtesy of Scott Nelson, UH-College of Tropical Agriculture and Human Resources

 (BBTV)

Banana bunchy top virus  is a devastating pathogen that affects banana plants. BBTV stunts the growth of banana plants and fruit. There is no cure for this virus and banana plants will stop producing fruit and die. BBTV is spread between plants by the banana aphid (Pentalonia nigronervosa), and people introduce the disease by moving infected plant material into the area.

 Watch a video:

 Description:

  • shrunken malformed leaves “bunching” at the top
  • “Morse code” dark green streaking on the leaf stem
  • mottled and streaked flowers
  • dark green streaks with “J” shape on midrib
  • presence of the banana aphid (Pentalonia nigronervosa)

Harm:

  • BBTV stunts the growth of banana plants and fruit.
  • There is no cure for this virus and banana plants will stop producing fruit and die.
  • BBTV is spread between plants by the banana aphid (Pentalonia nigronervosa).
  • People introduce the disease by moving infected plant material into the area.
  • All plants with BBTV should be quarantined and destroyed.

In Hawaii:

  • Statewide – Banana bunchy top virus was first introduced to Hawai‘i in 1989. It was first seen on O‘ahu, then the disease made its way to the Big Island followed by Kauai.
  • Maui – first detected in Pukalani in 2002. Since then, it has been found in Pukalani, Makawao, Kula, Kahului, Lahaina and Kīhei. As of 2014, BBTV is limited in West Maui, scattered in Haiku, and not known from the Keanae/Hana/Kipahulu area.

Don’t confuse with:

  • Cucumber Mosaic Virus (CMV) is also spread by the banana aphid, but does not cause significant damage to banana fruit. Symptoms are mottling and streaking flowers. CMV does not cause the “Morse code” leaf streaking pattern of BBTV infected plants.
  • Severe deficiencies of nutrients like calcium and boron cause yellowing and deformed growth of leaves.

For more information, see:

  • BBTV information from CTAHR
  • BBTV article from the MISC Kia’i Moku Column

Little Fire Ant

Find aerial treatment schedule for Nahiku here: Nahiku LFA Aerial Treatment

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:

For more information, see:

Miconia

(Miconia calvescens)

Family: Melastomataceae

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:

  • Large tree grows up to 50 feet tall
  • Large oval-shaped leaves, green on top, purple underneath, with three main midribs running from stem to leaf-tip
  • Native to South and Central America, introduced to Hawaii as a garden plant in 1961 and spread around by plant enthusiasts

Harm:

  • Forms thick stands, shades out native plants and completely takes over moist and wet forests
  • Forms an “umbrella” over the watershed, potentially reducing the amount of rainwater that seeps into the watershed.
  • Shallow root systems promote erosion
  • Can grow from seed to mature seeding tree in four years. A mature tree can produce about 3 million seeds several times per year. Seeds can remain viable for 10 or more years before sprouting
  • Sand-grained sized seeds easily spread by birds and other animals when they eat the fruit. Seeds also spread by people when contaminated dirt or mud sticks to shoes, clothing, equipment, or vehicles
  • Introduced to Tahiti in 1937 and has since overwhelmed two-thirds of Tahiti’s forests, and is directly responsible for threatening 25% of their native forest species with extinction

In Hawaii:

  • Kauai – One population known, in the Wailua State Park and Homesteads area. KISC works with partners to survey for and control all known miconia on Kauai. Land owners and tenants can allow KISC to survey their property and eradicate miconia.
  • Oahu – Originally introduced and traded amongst botanical gardens in the early 1960’s, miconia has since spread into several locations in the Koolau range. The potential population boundary extends to 9,500 acres (including areas considered “seed banks”). If left uncontrolled, miconia could infest up to 121,300 acres on Oahu. OISC is working to survey all population boundaries to completely eradicate it from Oahu.
  • Maui – Introduced to Maui in the early 1970s at a private nursery and botanical gardens near Hana. Infestations now occur in the forests near Hana, Nahiku, Keanae and Huelo. Today, approximately 37,000 acres throughout East Maui, could potentially contain miconia. Eradication is unlikely and resource managers hope to keep the species contained until an effective natural enemy can be found. Miconia is not known from West Maui.
  • Molokai – Miconia is not known to be present at this time. Seeds could arrive in soil on hiker’s or hunter’s shoes or gear, or on native tree fern logs imported from the Big Island. MoMISC educates community members to aid in early detection.
  • Lanai – None known.
  • Kahoolawe – None known.

For more information, see:

Coqui Frog

(Eleutherodactylus coqui)

Order: Anura

coqui1

Click on the image to hear the sound of a male Coqui frog

All frogs in the order Anura are Hawaii State Injurious Species. It is prohibited to release Injurious Species into the wild; transport them to islands or locations within the State where they are not already established; or export outside the State.

Description:

  • Small, nocturnal (night-active) frog about the size of a quarter, up to two inches in length
  • Usually brown or gray-brown, may have a lighter stripe down its back
  • Male’s mating call is a two-note, high-pitched “co-qui” (pronounced ko-kee)
  • Native to Puerto Rico, accidentally introduced to Hawaii hidden in plants around or before 1988

Harm:

  • No natural predators to keep populations in check (and no natural competitors), populations have reached 55,000 frogs per hectare in some Hawaii populations (24,000 frogs per hectare in Puerto Rico)
  • Eat huge quantities of insects, removing insects from forest floor to treetops.
  • Loss of insect services such as pollination
  • Disrupt the balance of vulnerable native ecosystems
  • Potential food source for snakes if they were to arrive
  • Loud, incessant and annoying call from dusk until dawn
  • Adverse economic impacts on tourism
  • Decreased export plant sales
  • Disclosure requirement for real estate transactions, has resulted in decreased property values in some locations

In Hawaii:

  • Kauai – A breeding population of coqui covering about 10 acres was discovered in Lawai in 2001. After extensive efforts by KISC and partner agencies to eradicate coqui from Kauai, the island was declared officially coqui-free in June, 2012.
  • Oahu – The only wild land population, located in Wahiawa, had over 100 calling frogs. Due to the efforts of HDOA, OISC, Oahu Army Natural Resources Program and DLNR, this population has been eradicated. Frogs are still found at nurseries and the owners are cooperating with the Oahu Coqui Frog Working Group.
    On Oahu and think you hear coqui?
    Call 643-PEST or click here for more information.
  • Maui – Thirteen populations in/around nurseries and hotels, residential areas and several large natural area populations. MISC has a full-time crew that spends a majority of their time clearing habitat and controlling coqui frogs within Maui’s populations.
    On Maui and think you hear coqui?
  • Molokai – There are currently no populations of coqui on Molokai. MoMISC works to educate community members to aid in early detection, which succeeded in 2002 when a lone calling coqui was reported and subsequently captured by MoMISC.

For more information, see:

Tips for Maui Residents:

 

Research:

PCSU logo

Contact Us

Maui Invasive Species Committee (MISC)
Office: (808) 573-6472
Press and Media Inquiries: (808) 344-2756
Mailing Address:
PO Box 983, Makawao, HI 96768

Acting Manager / Public Relations: Lissa Strohecker
E-mail: miscpr@hawaii.edu

Special Projects: Teya Penniman
E-mail: miscmgr@hawaii.edu

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