Ebola and IAS

A conversation with Dr Arne Witt

Dr Arne WittThe recent outbreak of Ebola virus disease in West Africa made headline news around the world. During the outbreak this fatal disease, endemic to parts of Central and West Africa, rapidly spread from Guinea, Sierra Leone, and Liberia to other countries in the region such as Nigeria, Mali and Senegal and then further afield to the USA, UK and Spain, mainly through infected health workers. This prompted decisive action from governments around the world and led to the implementation of strict controls at most national points of entry – as a result of this action and increased awareness, the further spread of this disease was effectively halted. No new infections have been reported for a number of months now but the cost has been significant – more than 10,000 people lost their lives, mainly in Guinea, Sierra Leone, and Liberia. However, it is highly probable that without significant interventions the costs could have been far higher. For example, the outbreak of bubonic plague or Black Death in Europe in the 17th century resulted in the death of 34 million people. The accidental introduction of potato blight, a crop disease which affects potatoes, from the Americas to Ireland in the mid-1800s contributed to the starvation of about 1 million people. Rinderpest, a disease affecting livestock was accidentally introduced to Africa from Asia in the late 19th century resulting in the deaths of, it is claimed, a third of the human population of what is now Ethiopia and two-thirds of the Maasai, an ethnic group of pastoralists in East Africa who are totally dependent on livestock. We may ask what Ebola, potato blight and rinderpest have in common – well obviously they have all have had a devastating impact on humanity but what binds them all together is that they are all INVASIVE ALIEN SPECIES (IAS). Fortunately, due to concerted efforts by a range of agencies rinderpest has been eradicated from the planet but as a result of increased trade, travel and tourism more and more species are being moved around the world and many are establishing and are continuing to have devastating impact on livelihoods. Read more of this post

Tackling Tutsan

Tutsan (Hypericum androsaemum) is invasive to New Zealand and Australia. Native to many countries throughout Europe and western parts of Asia, it is thought to have been introduced as a garden ornamental by acclimatisation societies in the 1800s due to its attractive yellow flower. Today, tutsan is a severe weed in several regions of New Zealand, most significantly affecting the Ruapehu District and Bay of Plenty region in the North Island. Over the last 20 years, tutsan has become an increasing problem in these regions; spreading throughout low fertility pastures and along roadsides. There is concern that tutsan has the potential to pose a significant conservation threat if it continues to spread at its current rate through scrub and native forest fringes.

Flowering tutsan plants growing in New Zealand (photo: Lizzie Rendell, 2011)

Flowering tutsan plants growing in New Zealand (photo: Lizzie Rendell, 2011)

Recent estimates indicate that around 150,000 ha of land in the Ruapehu district is affected by tutsan. Within the district, the annual cost of controlling the weed, and loss of farming profit amount to around $NZ1.2 million (£600,000), and loss of current land values is estimated at $NZ27 million (£13 million). Tutsan is a persistent weed for which there are no registered chemicals. Off-label herbicides are currently used in an attempt to limit its spread, but these are proving ineffective with stands typically reappearing several years later. The weed is unpalatable to stock and the topography of the region’s worst affected areas further limits the control methods possible. Read more of this post

Tuta absoluta on the rampage in Africa

Watch a new video illustrating the devastating impacts that Tuta absoluta is having on tomato yields, and what this means for farmers who rely on these crops for sustenance and income.

Dr Arne Witt, from CABI commented on the implications of Tuta absoluta infestation across Africa

“Tomatoes are one of the most widely cultivated crops in Africa and are grown in the backyards of almost every homestead across sub-Saharan Africa. This important cash crop and source of vitamins is now threatened by the recent arrival of the tomato leafminer, Tuta absoluta.

This Invasive Alien Species is rapidly moving down the African continent, having already decimated crops in Egypt, Ethiopia, Kenya and northern Tanzania. Growers are at their wits end as to how best they can control this pest and many have abandoned tomato growing altogether. The race is on to prevent its spread further south with various interventions planned to mitigate its impact in areas where it is already present.”

For more information on Tuta absoluta visit the Invasive Species Compendium and the Plantwise Knowledge Bank.

In the eye of the invasive species storm

17th September 2014 – Last weekend I experienced first-hand the impacts that invasive species can have. While carrying out research on an infestation of Opuntia Stricta in Laikipia, I felt something lodge itself in my eye. The following day I visited a specialist, as efforts to wash the thorn out of my eye had been unsuccessful.

They found that one of the very fine thorns, which are found on the fruit of the cactus, had become trapped in my eyelid and was scraping along the cornea. According to the specialist, another two days with the thorn in my eye would have resulted in me developing a corneal ulcer; which could have cost me my sight in that eye.

The thorns of Opuntia Stricta fruit are incredibly fine. So fine that the specialist was only able to detect it using microscopy equipment and dye. As well as being an unpleasant experience, this incident highlights the serious implications for those who live in areas which are infested with Opuntia Stricta, where many people would be unable to afford to seek medical help should they experience the same thing.

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Opuntia Stricta can also have a significant negative impact on livestock. If they get thorns in their eyes, there is no way for the owner to remove them. This could potentially result in loss of sight. Equally, it is not uncommon for goats to feed on the Opuntia fruit where the same thorns damage the goat’s stomach. This has been linked to the death of many animals in areas where this weed is prevalent as well as overgrazing in uninfected areas which is putting strain on pastoral land in these areas (Dodd, 1940).

While invasive species are often perceived as a biodiversity threat, they have a very real impact on the livelihoods and health of those who live in the areas in which they infest.

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.

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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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