Oahu Invasive Species Committee (OISC)

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NEW VOLUNTEER PROGRAMS COMING IN 2021!!


NEW & COMING IN JANUARY 2021!!! 

DEVIL WEED EARLY DETECTION TRAIL SURVEYS

Planning a hike? Want to help stop invasive species? We need your help to find out whether or not devil weed is present on Oʻahu’s trails. We simply don’t have the resources to survey all Oʻahu hiking trails for this invasive plant…so we are asking you to look for it on your next hike.

This is a community led effort to help OISC determine the spread of devil weed on Oʻahu. ANYONE can participate anytime!!

  1. Simply pick a trail from our list.
  2. Look for devil weed on the trail.
  3. Report whether or not you find it using a free smart phone app.

The list of trails and more details coming in late January 2021!!


NEW & COMING IN FEBRUARY 2021!!

JOIN THE DEVIL WEED CREW

We’re so excited to launch this new community volunteer program! Being part of the crew will mean you will really get to know (and love getting rid of) this invasive plant.

We are looking for people to commit to surveying specific areas and priority trails at least twice a year. There are also known areas on the island where Devil Weed is prevalent and large patches will need to be removed.

If you or your group is interested in participating, OISC will conduct virtual trainings every month on plant identification, how to manually remove large patches and mature plants, and how to report the data using a free smartphone app.

Are you interested in being part of the DEVIL WEED CREW?  Email us to get on the list for the first virtual training happening in February.

Contact Erin Bishop, OISC Outreach Coordinator. E: oisc@hawaii.edu, C: 808-286-4616

Filed Under: Home Slider, News & updates Tagged With: #devilweed, #volunteer

Benefits of Devil Weed (AKA Siam Weed) Removal in Australia

“The removal of Siam weed… appears to have resulted in health benefits, with locals reporting a reduced incidence of asthma caused by Siam weed,” Dr Atkins, of the Western Australia Department of Agriculture and Food. Read the article HERE.

Siam weed, more commonly known as devil weed in Hawaii, is one of OISC top priority target species! If you see this plant growing along the road, in your backyard or on your favorite hiking trail, report it to OISC immediately at oisc@hawaii.edu or call 266-7994.

Filed Under: Blog, News & updates Tagged With: #devilweed

Devil Weed

Do NOT pull or cut down the plant.  OISC will properly remove and dispose of the plant to prevent spreading seeds and re-sprouting. 

Please report devil weed to OISC. Send photo and location to oisc@hawaii.edu or text 808-286-4616. You can also call our office at 266-7994.

 

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Devil weed (Chromolaena odorata)

Family: Asteraceae

Devil weed (A.K.A Siam weed, bitter bush) is a well-documented pest and is considered one of the world’s worst 100 invasive species.   It is highly invasive and is on the Hawai’i State Noxious Weed List.   Devil weed received an extremely high score on the Hawai’i Weed Risk Assessment (HWRA), suggesting it has the potential to be exceedingly invasive in Hawai’i.

Description:

  • Herb or shrub with long rambling branches
  • Leaves are triangular shaped, opposite, with a toothed leaf edge.  Leaves are also limp with velvety hair and have a distinct turpentine smell when crushed.
  • The leaves have three thick veins shaped like a pitch fork, hence the common name “devil weed.”
  • Flowers are held in small clusters.  Pale purple to off-white, usually with distinct long stamens.
  • Fruits are tiny and have soft white hairs, which allow it to be spread on the wind or water. The hairs also act like Velcro, attaching themselves to anything passing by.
  • Native to tropical America.

Harm:

  • An aggressive colonizer of clearings and wet disturbed forests, creating dense thickets that impede growth and regeneration of native species.
  • Forms dense thickets 4-6 feet high.
  • Forms thick canopy that shades out other plants.
  • Releases toxins into the surrounding soil, reducing growth of other plants.
  • Toxic to livestock.
  • Forms monocultures, reducing biodiversity.
  • Consumes large amounts of water and negatively affect soil nutrient levels.
  • Can host pests and pathogens of kava/awa (Piper methysticum).
  • Each plant can produce 800,000 seeds each year, which are readily wind dispersed.
  • Sand-grained sized seeds are also easily spread by birds and other animals when they eat the fruit, and by people when dirt or mud containing the seeds stick to shoes, clothing, equipment, or vehicles.

On O’ahu

  • First detected in 2011 at the Kahuku Training Area, devil weed is now found in Kahana Valley, Pūpūkea and most recently in ’Aiea (2015). Kahuku Training Area is also the weekend home of the Kahuku Motocross Track, popular with motocross and dirt bike enthusiasts and hunters. Decontamination of bikes and hunting gear after use is necessary to prevent it from spreading across O’ahu, as well as to other islands.
  • OISC’s management goal for devil weed is island-wide detection and eradication.
  • Early detection and reporting are essential. Please call OISC at 286-4616 or email oisc@hawaii.edu to report devil weed.

Pest Alerts and Publications:

  • Devil Weed Rack Card
  • Devil Weed Pest Alert 
  • Chromolaena odorata Newsletter: Devil Weed in Hawaii

For more information, see:

  • Hawai’i State-listed Noxious Weeds
  • Global Invasive Species Database; Chromolaena odorata

KKC sizing up the CHRODO

Filed Under: OISC Priority Pests Tagged With: #devilweed

News & Updates

HISAM 2021 – Save the Date!

NEW VOLUNTEER PROGRAMS COMING IN 2021!!

October Is Stop The Ant Month in Hawai‘i

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Oahu Invasive Species Committee (OISC)
Office: (808) 266-7994
Fax: (808) 266-7995

OISC Manager: Nate Dube
E-mail: oiscmgr@hawaii.edu
OISC Outreach Coordinator: Erin Bishop
E-mail: oisc@hawaii.edu

Pest Hotline: 808-643-PEST (7378)
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