Review Category : Invasive Species

Devil Weed: Another Plant from Hell in Hawaii

By Franny Kinslow Brewer, Communications Director for the Big Island Invasive Species Committee (BIISC) Siam weed, bitter bush, jack in the bush, masigig, huluhagonoi, and triffid weed…no matter what common name you call it, Chromolaena odorata is named as one of the world’s worst 100 invasive species on the planet. So, when it popped up on O‘ahu in 2011 this plant from hell was referred to as devil weed here in Hawai‘i. Native Devil weed is native to South and Central America, the American Tropics, and the United States (Florida and Texas only ). It was first detected on O‘ahu by the Army Natural Resources Program during routine plant surveys at the Kahuku Training Area (KTA) in 2011. Following this initial detection, the Hawai‘i Pacific Weed Risk Assessment evaluated this plant species and calculated a score of 28 suggesting the potential to become highly invasive in Hawai‘i. This really isn’t a big surprise though. Devil weed has been rapidly invading lands from SE Asia, West Africa and South Africa, Australia... ...

Read More →

Are There Ants in Your Plants?

October is Stop the Ant Month! (Photo: Little Fire Ants (LFA) infestation under a nursery weed mat. Credit: Matt Sandrich/Hawaii Ant Lab) Native to South America, Little Fire Ants (LFA; Wasmannia auropunctata) were first detected in the Puna District of Hawai‘i Island in 1999. Since then, these tiny ants have been moved around hidden in plants, produce, and even things like vehicles and equipment from infested areas.  They continue to be intercepted in interisland cargo by agriculture inspectors, and crews continue to find and work to eradicate any new infestations on Kaua‘i, O‘ahu, and in Maui County. On Hawai‘i Island, LFA are established in many urban and non-urban areas, so communities are learning how to prevent, detect, and control the ant populations on their property and in their neighborhoods. Little fire ant queens remain in nests that are protected and fed by workers. These nests can be on the ground, in leaf litter, in plants, and even up in trees and in our homes. LFA may be tiny, but their stings are painful... ...

Read More →

IDENTIFYING AND RESTRICTING THE NEXT MICONIA

by Chelsea Arnott, CGAPS Planner   What if we knew about Miconia’s invasive impacts elsewhere and had been able to restrict it from importation and sale in Hawai`i? Today, we have the knowledge and tools to assess a plant’s potential to be invasive before it arrives, but we lack a regulatory mechanism to keep them out. Stemming in part from past LICH President Boyd Ready’s request to have a single list for prevention, the Coordinating Group on Alien Plant Species (CGAPS) has been working to develop a proposed State Restricted Plant List and set of rules that would reduce the risk of some future invasive plant introductions for Hawai`i. Historically, Hawaii’s geographic isolation limited the number of plants that were able to arrive and establish.  Since Western contact 240 years ago, more than 8,000 species of plants have been introduced to the islands. The majority of these have been either beneficial or at least benign. However, of those plants that became invasive to Hawaii’s natural areas, the majority (>80%) were intentionally introduced.... ...

Read More →

A New Menace for Containerized Plants

A New Menace for Containerized Plants by Molly Murphy A new naturalization record promises to add even more burden to the potted plant and landscape industry in Hawaii. Fatoua villosa commonly called hairy crabweed, was found naturalizing near recently planted pikake plants this past fall in Hilo. The potting mix contained copious amounts of viable seeds as well as numerous offspring. New recruits were detected in the vicinity and pulled out on subsequent trips to the Hilo garden. The herbarium at Bishop Museum documented reports of local naturalization in Oahu. Both Foster Botanical Garden and Lyon Arboretum were plagued with this nursery contaminant. It is unclear at this time if eradication was successful on Hawaii Island.  Hairy crabweed is a small, annual forb that is easy to overlook. In fact, it has a history of growing unnoticed only to be discovered after it is thoroughly established. The winter of 1962/1963 was particularly harsh in Louisiana, many plants died when temperatures dropped to 15 degrees F. Suddenly conspicuous against the barren landscape, the exotic species F. villosa was noticed... ...

Read More →

A Call to Arms / LFA Hui on Big Island

Hawai’i already suffers from more invasive species than any other state in the nation and remains constantly vulnerable to them due to its heavy reliance on imports.  Almost 90% of our food and a large number of plants come from the outside and provide avenues for their entry.  Once invasive species reach the Islands their impacts are often swift and severe due to our unique, fragile ecosystem.   Governor Ige recently summed up our vulnerability and the importance of immediate action in a single sentence: “Invasive species pose the single greatest threat to Hawaii’s economy and natural environment, and the health and lifestyle of Hawaii’s people.”   Despite these imminent dangers only 4% of the state budget is dedicated to addressing this paramount threat. Similarly, only a very small portion of the public is currently aware of these imminent dangers.   If the introduction of invasive species is left unchecked the consequences will be devastating, particularly in the case of the little fire ant (LFA).  Entomologists who have studied this... ...

Read More →

Report Card: Invasive Species Initiative

It’s been seven years since the industry was first introduced to the University of Hawaii Weed Risk Assessment, a tool for predicting the potential invasiveness of plants. In the beginning, the green industry struggled with the weed risk assessment, but a lot has changed since 2004. In 2006, the landscape industry started an initiative to determine which potentially invasive plants have greater risk than benefit. The initiative included broad outreach with numerous meetings on all islands including the Hawaii Island Landscape Association, Kauai Landscape Industry Council, Maui Association of Landscape Professionals, Oahu Nursery Growers Association, The Outdoor Circle, Hawaii Society of Urban Forestry, Aloha Arborist Association, Hawaii Landscape & Irrigation Contractors and the American Society of Landscape Architects. After three years of meetings and lengthy discussion, the industry came together and agreed that of the 168 plants listed as potentially invasive, that 80% would not be utilized. The Landscape Industry Council of Hawaii Invasive Species Guidelines and Invasive Plant List became on effective May 1, 2009. The list and the... ...

Read More →

Pest Roundup

Preventing new pests from entering our islands protects our environment, economy, and health, and it is a building block to a sustainable Hawaiʻi. Here are some prevention initiatives. New Pest Poster Available The landscape industry provides our state with more than 11,000 on-the-ground eyes and ears that can help protect Hawaiʻi from new pests.  To help identify some of the most unwanted landscape and nursery pests in the United States, the University of Hawaiʻi College of Tropical Agriculture and Human Resources (CTAHR) has produced a new poster.  The poster contains photos and descriptions of sixteen insect pests, their host plants, and known distribution.  Some of the featured pests include palm-killers like the red palm weevil (Rhynchophorus ferrugineus) and coconut rhinoceros beetle (Oryctes rhinoceros), and the lobate lac scale (Paratachardina pseudolobata), which officials in Florida consider one of the most devastating pests of trees and shrubs ever introduced.  New detections of these or other pests should be reported to the Hawaiʻi Department of Agriculture Pest Hotline at 643-PEST (643-7378).  For a... ...

Read More →

Featured Pest: The Spiraling Whitefly (Aleurodicus dispersus)

 Hosts: Recorded on 38 genera of plants from 27 plant families and over 100 different species. Common on vegetables, ornamental, fruit and shade tree crops in Hawaii, including avocado, banana, bird-or-paradise, breadfruit, citrus, coconut, eggplant, kamani, Indian banyan, macadamia, mango, palm, paperbark, papaya, pepper, pikake, plumeria, poinsettia, rose, sea grape, ti, and tropical almond. Distribution: Native to Central American and the Caribbean region.  First reported in Hawaii in 1978 and now present on all of the major islands. Damage:  a) Direct – damage caused by piercing and sucking of sap from foliage.  Majority of feeding done during the first three nymphal stages.  Usually insufficient to kill plants. b) Indirect – damage due to accumulated honeydew and white, waxy flocculent material.  The honeydew serves as a substrate for sooty mold, which blackens the leaf and decreases photosynthesis and plant vigor, and can cause disfigurement.  The flocculent material is spread by the wind and can create an unsightly nuisance. c) Virus transmission – damage from virus transmission can be considerable.  These viruses cause over 40... ...

Read More →