CABI releases rust fungus to control invasive weed, Himalayan balsam

26 August 2014 – From today, not-for-profit research organization, CABI, will be releasing a rust fungus at locations in Berkshire, Cornwall and Middlesex as part of field trials to control the non-native, invasive weed Himalayan balsam (Impatiens glandulifera) using natural means.

Himalayan balsam has rapidly become one of the UK’s most widespread invasive weeds, colonizing river banks, waste land, damp woodlands, roadways and railways. The Environment Agency estimates that the weed occupies over 13% of river banks in England and Wales. It can reach over three metres in height and competes with native plants, reducing biodiversity. Large scale chemical and manual control is often not feasible and not economically viable.

Himalayan balsam infestation on the river Torridge, Devon, UK

Himalayan balsam infestation on the river Torridge, Devon, UK (Rob Tanner, CABI)

Using existing measures, the Environment Agency estimates it would cost up to £300 million to eradicate Himalayan balsam from the UK.

The release of the rust fungus comes after an eight-year research programme funded primarily by Defra and the Environment Agency, with contributions from Network Rail, the Scottish Government and Westcountry Rivers Trust. During the course of the research, testing in quarantine laboratories has established that the rust fungus causes significant damage to Himalayan balsam and does not impact on native species.

Minister for natural environment, Lord de Mauley, says:

“This is a great step forwards in tackling Himalayan balsam. This invasive weed prevents our native plants from flourishing, can increase flood risk, and costs the British economy £1m per year to clean up. The work CABI has done in identifying a natural control method will help us reduce the impact of Himalayan balsam without any negative effects on native species.”

Senior Scientist at CABI, Dr Robert Tanner, says:

“The release of the rust fungus against Himalayan balsam is a result of over eight years of research evaluating the safety of its use against the target species. Over time, we should see a decline in the Himalayan balsam populations along our rivers, with native plant species recolonizing these degraded sites.”

To tackle the spread of Himalayan balsam, in 2006, CABI was commissioned to find a natural way to help control this destructive weed. The aim of CABI’s research was to find one of the many insects or fungi attacking the plant that had evolved to attack only Himalayan balsam, which could be released into the UK to control the weed while leaving indigenous species unharmed. CABI found that the rust fungus did just that.

Defra Ministers took the decision to allow CABI to release the rust fungus in July 2014. This decision followed the Food and Environment Research Agency’s (FERA) review of the scientific research and a public consultation on the proposed release of the fungus to control Himalayan balsam, which ran from May to June 2014.

For more information on Himalayan balsam go to http://himalayanbalsam.cabi.org

New in July 2014 from the ISC

In July 2014 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc

Senna multijuga (November shower) is a shrub or tree native to South America that has been introduced to tropical regions around the world. It is tolerant of a variety of soil types and its seeds are easily dispersed by wind and people. Despite its ability to naturalize quickly and its invasiveness in Hawaii, S. multijuga continues to be spread intentionally as an ornamental plant.

Senna multijuga Invasive Species Compendium datasheet

Senna multijuga Invasive Species Compendium datasheet

Abrus precatorius (rosary pea) is a high-climbing, twining or trailing woody vine from the Old World tropics. Although the plant has a wide variety of uses, from medicine, food and sweetener to jewellery, horticulture and even as a weighing unit, the seeds are so toxic that a single seed can kill a human. This vine is known to be invasive to Cuba and many parts of Asia-Pacific, and is naturalized in many tropical regions including Hawaii, parts of the Marquesas and Singapore.

Senna spectabilis (whitebark senna) – epithets range from ‘environmental weed’ to ‘garden thug’ for this resilient and fast-growing tree. Native to tropical America, S. spectabilis is considered invasive in Australia, Uganda, Tanzania, Hawaii, French Polynesia and Cuba. It can spread rapidly to create monocultures and place native flora at risk.

 

Other invasive species datasheets recently published include:

Senna surattensis (golden senna)

Senna bacillaris (whitebark senna)

New in April 2014 from the ISC

In April 2014 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc

Thunbergia alata (black eyed Susan) – Australia, Brazil, Central America and many Pacific islands are all threatened by this aggressive herbaceous vine. Once introduced into a suitable climate, often as an ornamental, it quickly establishes and spreads both sexually and vegetatively. T. alata is capable of smothering native vegetation, killing host trees, out-competing understory plants and negatively affecting the germination and establishment of native plants.

Thunbergia alata Invasive Species Compendium datasheet

Thunbergia alata Invasive Species Compendium datasheet

Indigofera hirsuta (hairy indigo) – native to Africa, Asia and Australia, this herbaceous legume has been widely introduced as a crop and forage plant. Its ability to adapt to a wide range of soil types, spread quickly and regenerate – even in burnt-out ground – has led it become invasive in many Pacific islands. It is also considered a weed in China, Brazil and parts of the USA.

Urochloa mutica (para grass) – U. mutica has been widely introduced to tropical and subtropical regions as a fodder grass. This species’ aggressive growth, high productivity and allelopathic abilities have allowed it to become one of the worst weeds in the USA, Mexico, Central America and Australia.

Other invasive species datasheets recently published include:

Allamanda cathartica (yellow allamanda)

Emilia fosbergii (Florida tassel-flower)

Zingiber zerumbet (shampoo ginger)

Nelsonia canescens (blue pussyleaf)

The XIV International Symposium on the Biological Control of Weeds, Kruger National Park, South Africa, March 2014

In March 156 delegates from 24 countries travelled to the Kruger National Park in South Africa to attend the XIV International Symposium on Biological Control of Weeds (ISBCW) which was held at the Nombolo Mdhuli situated in the Skukuza Camp (2 – 7 March 2014). This quadrennial international symposium is a prestigious conference which provides delegates with an opportunity to present novel research on all aspects of biological weed control, to reflect on past experiences and discuss the way forward for the discipline and – this goes without saying – to catch up with old friendships and forge new ones. Three years on from the previous symposium in Hawaii and timed to commemorate “100 years of weed biological control in South Africa” 1, the African continent hosted the meeting for the second time in its history (the first time being the IX ISBCW held in Stellenbosch, South Africa in 1996). However, perhaps partly because of the increasingly severe constraints on funding and failure to gain official approval from respective governments/organizations, which made it impossible for many people to attend, this year’s symposium saw lower delegate numbers than previous ones. Some of the traditional “strongholds” in weed biocontrol, i.e. Australia, USA and Canada were clearly underrepresented, while the high number of European participants reflected the rapidly increasing interest in weed biocontrol in this part of the world. Sadly, apart from the participants from South Africa, only one other African country (Kenya) was represented. Last, but not least, it was an important and positive feature of attendance at this symposium that up-and-coming, younger scientists from all over the world were very well represented and the presence, prominence and enthusiasm of the next generation of weed biocontrol scientists at the XIV ISBCW seems to bode well for the future of the discipline.

Nombolo Mdhuli Conference Centre, Skukuza Rest Camp, Kruger National Park

Nombolo Mdhuli Conference Centre, Skukuza Rest Camp, Kruger National Park. Host venue for the XIV International Symposium on the Biological Control of Weeds (Photo: Marion Seier)

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New in March 2014 from the ISC

In March 2014 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc

Bothriochloa pertusa (pitted beard grass) - B. pertusa is a perennial grass native to eastern and southern Asia. It has been widely introduced in the Americas, Australia and the Pacific, either accidentally or probably in some cases deliberately for use as a forage grass. It has established itself in many native habitats where it is able to out-compete many native species due to its ability to establish dense mats and shade out slower establishing species.

Bothriochloa pertusa Invasive Species Compendium datasheet

Bothriochloa pertusa Invasive Species Compendium datasheet

 

Portunus segnis (blue swimming crab) – P. segnis is a marine nocturnal crab native to the western Indian Ocean. It is now considered established in the Mediterranean but invasive in the east and potentially invasive in the central and western Mediterranean. It is an active predator, tolerant to a wide range of temperatures and salinities and capable of reproducing throughout the year, with long-lived planktonic larval stages. Global warming is also expected to favour this tropical species.

Xanthium spinosum (bathurst burr) – X. spinosum is a highly invasive plant classified as one of the world’s worst weeds. It is now widely distributed throughout many regions of the world, where it is a common agricultural and pasture weed and a declared noxious species in many countries. Originating in South America, it has spread widely, probably via its spiked seeds which attach to animals and clothing or are a contaminant of hay or other products. It produces prolific amounts of seed that germinate easily. X. spinosum can quickly dominate large areas, outcompeting crops, forage plants and native flora. Control is possible but requires significant effort. There is considerable ongoing research into various methods including biological control.

 

Other invasive species datasheets recently published include:

Anredera cordifolia (Madeira vine)

Anthoxanthum odoratum (sweet vernal grass)

Opuntia monocantha (common prickly pear)

Green Invasion: Destroying Livelihoods in Africa [Video]

CABI, together with Tmax Productions, have produced a video called the ‘Green Invasion – Destroying Livelihoods in Africa.” The short film (approx. 7mins long) details how invasive weeds are impacting on the lives of rural communities in East Africa.

Although a large number of non-native species have become invasive in the region, this film focusses on four of the most problematic species namely Chromolaena odorata (Devil weed), Parthenium hysterophorus (famine weed), Prosopis juliflora (Mathenge) and Opuntia stricta (erect prickly pear). The excellent footage shows the extent of  weed infestations with accounts from community members on how these invasive plants are destroying the natural resource base on which they depend. It is clear that invasive weeds are destroying traditions, cultures and a way of life for millions of people on the continent.

However, all is not lost. The film notes that if effective management programmes are implemented, including biological control, we can make a difference to many people’s lives.

Although of general interest, the film is intended to raise the profile of invasive species and their impacts on livelihoods amongst donors and governments. We need them to take action and provide support for initiatives to manage one of the biggest threats to economic development on the planet.

Arne Witt
CABI Regional Coordinator, Invasives (Africa & Asia)
@WittArne


New in February 2014 from the ISC

In February 2014 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc

Drosophila suzukii - The damage caused by D. suzukii larvae renders fruit unmarketable. In 2008 economic losses (based on maximum reported yield losses) for California, Oregon and Washington were estimated at 40% for blueberries, 50% for caneberries, 33% for cherries and 20% for strawberries. Production in these three states could sustain $511 million in damages annually because of D. suzukii. D. suzukii produces up to five times more hemocytes than D. melanogaster, making it significantly more resistant to wasp parasitism and making it less likely for indigenous specialized parasitoids to shift host onto it.

Drosophila suzukii ISC datasheet

Drosophila suzukii Invasive Species Compendium datasheet

Rattus rattus – R. rattus has directly caused or contributed to the extinction of many species of wildlife including birds, small mammals, reptiles, invertebrates and plants, especially on islands. The primary economic impact of R. rattus relates to agricultural and horticultural damage. It is capable of destroying up to 30% of crops annually. Phylogenetic restructuring of the ‘Rattus rattus complex’ (comprising the oceanic and Asian groups) is on-going. Based on molecular evidence, there are multiple species within what has historically been identified as Rattus rattus.

Leonurus japonicus – L. japonicus is a highly invasive weed widely naturalized in tropical and subtropical ecosystems. It commonly grows as a weed in waste places, disturbed sites and along roadsides and as an ornamental in gardens and yards. L. japonicus also invades pastures and arable land as well as coastal and dry forests. In a recent work, Xiong, et al. (2013) described the chemical composition and the antibacterial activity of essential oils from different parts of L. japonicus. These essential oils showed antibacterial activity against various Gram-positive bacteria.

Other invasive species datasheets recently published include…

Chamaecrista nictitans

Medicago polymorpha

Pantherophis guttatus

Amphisbaena fuliginosa

Datura ferox

Schilbe mystus

Protopterus aethiopicus

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