New in October 2015 from the ISC

In October 2015 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here:

Forest & Kim Starr [CC BY 3.0 (], via Wikimedia Commons

1. Mysore raspberry

Rubus niveus (Mysore raspberry)

Rubus niveus is an invasive blackberry which is threatening the endemic wildlife of the Galapagos Islands. More specifically, it is a threat to the unusual daisy tree forests (of the Scalesia genus). R. niveus now covers around 30,000 ha of the islands and can grow up to 3 m tall. CABI scientists are searching for potential biocontrol agents from the Asian native range of the blackberry to introduce here. Find about more about this project.

Christian Fischer [CC BY-SA 3.0 (], via Wikimedia Commons

2. Common knotweed

Polygonum arenastrum (common knotweed)

This species is considered to be one of the world’s most economically important weeds. It is a host of various pathogens which damage crops such as alfalfa, potato and parsnip. Phytotoxic chemicals are produced by the plant that can inhibit the establishment of black medic (Medicago lupulina) and other plant species. It can also affect rhizome bacteria which are important for legume species such as peas and beans. The weed is very resilient as it possesses a long taproot which helps it survive drought.

Forest & Kim Starr [CC BY 3.0 (], via Wikimedia Commons

3. Love-vine

Cassytha filiformis (love-vine)

Invasive in its broad native range (Asia, Africa, America, Oceania), Cassytha filiformis is a parasitic vine that is primarily found in coastal areas. In the Chagos archipelago (Indian Ocean) it is seriously reducing populations of beach cabbage (Scaevola taccada) and increasing the risk of erosion. C. filiformis extracts plant sap from its host and covers it with a dense mat of stems. The sheer weight of its stems can break branches – this is particularly problematic when its host is a crop, such as a citrus tree.


Forest & Kim Starr [CC BY 3.0 (], via Wikimedia Commons

4. Portia tree

Thespesia populnea (portia tree)

Thespesia populnea is an Old World, tropical, coastal species that is often found in and around mangroves. Its buoyant and hardy seeds can survive even after a year in seawater. It produces dark, red-brown, strong and hard ‘milo’ wood that is highly valued on Pacific islands. However, it can form dense thickets and reproduces profusely. It is listed as an invasive species in the Bahamas, Florida and Puerto Rico.

Hypogeococcus pungens (cactus mealybug)

Hypogeococcus pungens is a mealybug, native to South America, which was used as a biological control agent of invasive cacti in the subfamily Cactoideae in Queensland, Australia, and in South Africa. Since then, it has become an invasive species itself. It is a threat to native cacti in Florida and Hawaii (USA), Barbados and other Caribbean islands. In addition to cacti, its wide range of hosts includes species within the ornamental plant families Portulacaceae, Apocynaceae and Amaranthaceae.

Other new datasheets published in October include:

Baccharis pilularis (coyote brush)
Cuphea carthagenensis (Colombian waxweed)
Cyrtomium falcatum (Japanese holly fern)
Epilobium ciliatum (northern willowherb)
Maliarpha separatella (African white rice borer)

Figure references

  1. Mysore raspberry by Forest & Kim Starr [CC BY 3.0 (, via Wikimedia Commons
  2. Common knotweed by Christian Fischer [CC BY-SA 3.0 (, via Wikimedia Commons
  3. Love-vine by Forest & Kim Starr [CC BY 3.0 (, via Wikimedia Commons
  4. Portia tree by Forest & Kim Starr [CC BY 3.0 (, via Wikimedia Commons

New in September 2015 from the ISC

In September 2015 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here:

Common mullein by Fritz Geller-Grimm (Own work) [CC BY-SA 3.0 (, CC BY-SA 3.0 (, GFDL ( or CC BY-SA 3.0 (], via Wikimedia Commons

1. Common mullein

Verbascum thapsus (common mullein)

A biennial herb which has naturalized in most temperate regions of the world. It grows vigorously, threatening native plants in meadows and forest gaps. Eradication is extremely difficult since each individual can produce 100,000-175,000 seeds that can remain viable for more than 100 years.

Fibropapillomatosis of sea turtles by Peter Bennett & Ursula Keuper-Bennett (Original photograph) [GFDL ( or CC BY 3.0 (], via Wikimedia Commons

2. Fibropapillomatosis

Fibropapillomatosis of sea turtles

A disease which most commonly affects the endangered green turtle. It causes internal and external tumours which can obstruct crucial functions such as swimming and feeding. First reported in the 1930s in Florida, it is now a pandemic.

Grey snake-bark maple by KENPEI (KENPEI's photo) [GFDL (, CC-BY-SA-3.0 ( or CC BY-SA 2.1 jp (], via Wikimedia Commons Mnemiopsis leidyi (sea walnut)

3. Grey snake-bark maple

Acer rufinerve (grey snake-bark maple)

With striped grey-green bark this tree is aptly named. It produces dense thickets and has been reported as an aggressive coloniser in acidic forests in Belgium. It has been introduced around the world as an ornamental plant, like so many other invasive species.

Sea walnut by No machine-readable author provided. Bastique assumed (based on copyright claims). [GFDL (, CC-BY-SA-3.0 ( or CC BY-SA 2.5-2.0-1.0 (], via Wikimedia Commons

4. Sea walnut

Mnemiopsis leidyi (sea walnut)

Being a comb jelly, this marine species has rows of ‘combs’ (groups of cilia) which it uses for swimming. It is an ‘ecosystem engineer’ which can change water transparency and water nutrient content. It has the impressive ability to regenerate from fragments larger than one-quarter of an individual.


Ficus microcarpa (Indian laurel tree)

A high-risk, aggressively invasive, strangling fig which is an agricultural weed and “garden thug” – how much worse could it be!? Reportedly invasive to some places where its specialist pollinator wasp has also been introduced. It starts life as an epiphyte, growing on a tree’s surface, before sending its aerial roots down to the ground. The roots end up forming a lattice around the trunk of the host tree which remains after the host tree dies.

Figure references

  1. Common mullein by Fritz Geller-Grimm (Own work) [CC BY-SA 3.0 (, CC BY-SA 3.0 (, GFDL ( or CC BY-SA 3.0 (, via Wikimedia Commons
  2. Fibropapillomatosis of green turtle by Peter Bennett & Ursula Keuper-Bennett (Original photograph) [GFDL ( or CC BY 3.0 (, via Wikimedia Commons
  3. Grey snake-bark maple by KENPEI (KENPEI’s photo) [GFDL (, CC-BY-SA-3.0 ( or CC BY-SA 2.1 jp (, via Wikimedia Commons
  4. Sea walnut by ‘No machine-readable author provided’. Bastique assumed (based on copyright claims). [GFDL (, CC-BY-SA-3.0 ( or CC BY-SA 2.5-2.0-1.0 (, via Wikimedia Commons

New in July 2015 from the ISC

In July 2015 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here:

July invasivesAkebia quinata (five-leaf akebia) – a highly invasive, aggressive vine native to East Asia, A. quinata has been introduced as an ornamental to Canada, Europe, Oceania and the USA. It can outcompete native understory plants and young trees, and its dense growth can block sunlight and prevent the germination of native plants.

Geophagus brasiliensis (pearl cichlid) – an ornamental freshwater fish native to southeast Brazil, G. brasiliensis has been introduced to Australia, Florida, the Philippines and Taiwan. Its fast growth, opportunistic diet and broad environmental tolerances have allowed it to colonize new waterways, particularly artificial and disturbed habitats.

Rudbeckia laciniata (thimbleweed)R. laciniata is an ornamental perennial plant that has been introduced to China, Japan, New Zealand and Europe. Native to eastern North America, thimbleweed grows best in bright, humid areas, such as wetlands, forest edges and roadsides. By producing lots of seeds and spreading from rhizome fragments, it can form dense monocultures which outcompete native plants.

Other invasive species datasheets recently published include:

Brugmansia suaveolens (white angel’s trumpet)
Chrysemys picta (painted turtle)
Macaranga tanarius (parasol leaf tree)
Paederia foetida (skunkvine)
Umbra pygmaea (eastern mudminnow)

Investigating the impacts of the invasive species Prosopis in Baringo, Kenya

The Baringo district northwest of Nairobi is one of the regions in Kenya where a number of mesquite species, Prosopis spp., were introduced some 40 years ago as part of poverty alleviation efforts. The trees were intended to provide, among other benefits, additional income.

Today Baringo is one of the most heavily invaded regions in eastern Africa, with severe consequences for the rural communities. As part of the kick-off meeting of the recently launched, Swiss government funded R4D (research for development) project called “Woody Weeds”, the project team visited the district, one of the case study areas in the project.

During this two-day visit, two communities were visited which suffered from high Prosopis invasion levels. These communities gave an interesting first insight into the dilemmas that have arisen due to Prosopis invasion. The first community we visited utilizes Prosopis for charcoal production and hopes to benefit in the future also from selling Prosopis wood to a local power plant; by utilizing this invasive species the community members gain some financial benefits and at the same time reduce the impacts of this plant on their land.

Irrespective of how the local communities deal with this invasive species, one of the main challenges in management is to find ways to slow down or reduce the spread of Prosopis and mitigate its negative impacts in Baringo (and elsewhere). While the government of Kenya supports local communities in utilizing Prosopis, there is, so far, little scientific evidence that utilization indeed slows down or even stops the spread of this aggressive invader.

One of the key tasks of the “Woody Weeds” project will therefore be the evaluation of the impacts on the environment and rural livelihoods of the various management options against Prosopis and other woody invasive species, such as management by utilization, physical, chemical or biological control, or doing nothing, and to inform decision-makers about the key findings.

Urs Schaffner, CABI

New in June 2015 from the ISC

It’s been a bumper month for the ISC, with 42 new datasheets published and the total number of full datasheets topping 2000. You can explore the open-access ISC here:

A selection of new datasheets published to the ISC in June 2015.

A selection of new datasheets published to the ISC in June 2015.

Bothriocephalus acheilognathi (Asian fish tapeworm) – in the past few decades this tapeworm has spread from its native East Asia to all continents except Antarctica, largely thanks to the aquaculture and pet trade. A parasite of over 200 fish species, infections of B. acheilognathi negatively impact the aquaculture industry and have been responsible for 90% mortality rate in grass carp in the past. Environmental impacts are still largely unknown, but the Asian fish tapeworm is thought to be adversely affecting some endangered species.

Deparia petersenii subsp. petersenii (Petersen’s lady fern) – an aggressive, fast-growing perennial fern that can form thick ground cover and outcompete native plants. Native to Asia, New Guinea and Polynesia, Petersen’s lady fern has been introduced as an ornamental and is now invasive in Madeira, the Azores, southeastern USA, southeastern Brazil and Hawaii.

Trioceros jacksonii (Jackson’s chameleon) – native to Kenya and Tanzania, this chameleon has been introduced via the pet trade to California and Hawaii. It may pose a threat to native Hawaiian insects and snails that it preys on.

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On the trail of an ancient invasive

‘if men were not employed to prune these trees… they would cover the country, completely invading it.’

Sound familiar? It could be a description of any number of invasive trees, from the trumpet tree (Cecropia peltata) spreading through West Africa to the candlenut tree (Aleurites moluccanus) currently invading Pacific islands. But it’s actually an account by Mas’ūdī, writing over a thousand years ago in the Islamic year 332 (943 CE).

Ficus benjamina

Has Ficus been a problem for over a thousand years?    © K.M. Kochummen.

Born in Baghdad around 890 CE, Mas’ūdī was a prolific writer and adventurer extraordinaire. His world-history-meets-travelogue, The Meadows of Gold, contains many fantastic stories, from jewelled tombs to Viking battles, but it was his account of an apparent invasive – referred to simply as the banyan tree – that caught my attention, and I was keen to find out more.

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The impacts of invasive weeds in Chitwan National Park, Nepal

Mikania (Mikania micrantha) is a tropical vine which is native to the Americas. Often referred to as the ‘Mile-a-Minute Weed,’ mikania grows rapidly in areas of high rainfall and has become highly invasive in parts of Asia and the Pacific. Under the Convention on Biological Diversity, invasive species are defined as alien species that threaten native ecosystems, habitats or species and in Nepal, mikania and other invasive plants such as chromolaena (Chromolaena odorata) are becoming increasingly problematic within the Chitwan National Park (CNP). There, the plants are having a serious negative impact on native grasses, shrubs and the one-horned rhinoceros, and by implication, deer and tiger populations. They are also affecting the local people who reside in the buffer zones and rely on the park for fodder and other materials.

A rhino amongst chromolaena

A rhino amongst chromolaena


In a specific study on mikania, scientists from the National Trust for Nature Conservation, Nepal with support from CABI and the Zoological Society of London have found a significant negative relationship between high mikania coverage and the population of rhinos. This is because the mikania vine smothers the fodder plants that the rhinos feed on. This could also be influencing their movement to other areas of the park where they feed on resources and crops important to local people. This in turn may exacerbate conflict between the residents of the buffer zones and the wildlife in the area.

Deer and Tigers

The reduction in fodder plants is likely also to cause a mirrored decrease in the number of deer in the park. Deer feed on similar plants to the rhinos and the impact of mikania on native vegetation is therefore likely to affect their feeding behaviour in a comparable manner. As a result a decrease in deer numbers is likely to have a negative impact on tiger populations, with tiger numbers being directly related to the populations of their prey.

Local people

The residents of the buffer zones surrounding the CNP are known to rely on the core area of the park for resources such as fodder, which they use to feed their livestock. These residents recognise that fodder availability within the park has decreased and report that collecting materials now takes three times as long as it has in previous years to gather the same amount of fodder. Reduced fodder has been attributed to flooding of the park and the spread of invasive plant species. In particular, a high proportion of local residents report that mikania has a significant negative impact on the fodder growing in the park.

Sustainable control of mikania weed

CABI piloted using a rust fungus (Puccinia spegazzinii) as a classical biological control agent for mikania weed in India. This highly host specific and damaging pathogen has now been released in Papua New Guinea and Taiwan, where it is having a significant impact on the growth of the weed. The rust has recently been released on a number of other Pacific Islands, and could be considered for release in Nepal.


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