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.

New in January 2015 from the ISC

In January 2015 the following datasheets were published on CABI’s Invasive Species Compendium (ISC). You can explore the open-access ISC here: www.cabi.org/isc.

Clerodendrum thomsoniae Invasive Species Compendium datasheet

Clerodendrum thomsoniae Invasive Species Compendium datasheet

Clerodendrum thomsoniae (bleeding glory bower)native to West Africa, this vine has been widely cultivated in tropics and subtropics worldwide, and is naturalised in many places, including the USA, Australia and the Galapagos Islands. Despite being related to some particularly serious invasives, such as C. chinense and C. quadriloculare, the impacts of bleeding glory bower are so far limited.

Cortaderia jubata (purple pampas grass)familiar to many of us as a garden ornamental, C. jubata is a multipurpose tussock grass native to South America. Surprise surprise, this towering, fast-growing, prolific plant has become a serious invasive in several places around the world, displacing native vegetation and suppressing the growth of young trees. Dense stands of C. jubata can also pose a fire hazard.

Opuntia monacantha (common prickly pear) – another introduced Opuntia, another tale of woe. Opuntia monacantha has been introduced around the world as a fruit and fodder plant since the 1700s. Its ability to regrow from broken and scattered cladodes allows it to quickly form dense, impenetrable thickets. Fortunately, biocontrol of the common prickly pear has proved successful in several countries.

New in November 2014 from the ISC

In November 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

Clerodendrum indicum Invasive Species Compendium datasheet

Clerodendrum indicum Invasive Species Compendium datasheet

Clerodendrum indicum (Turk’s turban) – this small shrub, native to temperate and tropical Asia, has been deliberately introduced principally to the Americas as an ornamental. Having long since escaped from cultivation, it is now established in the neotropics. Rapid growth and the ability to reproduce by seeds, rooted cuttings and suckers have contributed to its spread, although C. indicum does not appear to be as invasive as other species in the Clerodendrum cohort.

Potamopyrgus antipodarum (New Zealand mudsnail) – native to New Zealand, this aquatic snail has been introduced to Europe, North America, Australia and Asia. Females are parthenogenetic, meaning they can reproduce without males. This allows a new population to be founded by a single female – and with an average of 230 offspring per adult per year, P. antipodarum can quickly become very abundant. Its ability to survive desiccation for several days allows this snail to be spread by birds and anglers. It is currently considered invasive in Spain, USA and Australia.

Cosmos caudatus (wild cosmos) – thanks to its prolific seed production wild cosmos can cause chaos in the tropics, where its fast growth and height (up to 2.5 m tall) makes it difficult to control. Thought to be native to southern Mexico, it is now found in Asia, Africa, throughout the Americas, Australia and some Pacific islands. C. caudatus is particularly adept at spreading in disturbed areas, pastures and roadsides.

 

Other invasive species datasheets recently published include:

Cyclosorus parasiticus (parasitic maiden fern)
Vulpia myuros (annual fescue)
Clerodendrum bungei (rose glorybower)

New in October 2014 from the ISC

In October 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

Silybum marianum Invasive Species Compendium datasheet

Silybum marianum Invasive Species Compendium datasheet

Silybum marianum (variegated thistle) – this large, aggressive thistle was already recognised as a serious invasive way back in the 1800s. Native to the Mediterranean and parts of Asia and Russia, S. marianum is now present on every continent except Antarctica. Standing up to two metres tall, and armed with a spiky flowerhead and prickly leaves, the thistle can outcompete native plants, swamp farmland and impede the movement of people and animals. If eaten, S. marinaum can cause potentially fatal nitrate poisoning.

Lumbricus terrestris (lob worm) – after more than 2000 years of human-mediated introductions, the humble earthworm is now found in South Africa, India, Australia, New Zealand, Europe and North America, where it has picked up the exciting name nightcrawler. When introduced to an environment lacking native earthworms, L. terrestris can dramatically alter soil profiles. Thick leaf mats are quickly converted to humus, depriving native invertebrates of a habitat, altering the microbial community and changing the chemistry of the forest floor.

Cestrum nocturnum (night jessamine) – native to Central America, this showy and fragrant but toxic shrub is now widespread throughout the Old and New World tropics, where it forms dense thickets that crowd out native flora. Its small and profuse seed means there is a high risk of further introductions. C. nocturnum is known to be invasive in Hawaii, the Cook Islands, Fiji, French Polynesia, Western Samoa, Tonga, New Caledonia and New Zealand.

Other invasive species datasheets recently published include:

Acacia hockii (white thorn acacia)
Amaranthus dubius (spleen amaranth)
Dipsacus fullonum (common teasel)
Ehrharta erecta (panic veldtgrass)
Erodium botrys (long-beaked stork’s bill)
Erodium cicutarium (common storksbill)
Gaillardia pulchella (Indian blanket)
Glechoma hederacea (ground ivy)
Hypochaeris radicata (cat’s ear)
Juncus planifolius (broadleaf rush)
Lactuca floridana (woodland lettuce)
Lolium perenne (perennial ryegrass)
Lonicera maackii (Amur honeysuckle)
Malva pusilla (round-leaved mallow)
Marrubium vulgare (horehound)
Melilotus albus (honey clover)
Mentha pulegium (pennyroyal)
Nasturtium microphyllum (one-row watercress)
Odontonema callistachyum (purple firespike)
Oryza barthii (African annual wild rice)
Oxalis corniculata (creeping woodsorrel)
Parentucellia viscosa (yellow glandweed)
Paspalidium geminatum (Egyptian paspalidium)
Persicaria punctata (dotted smartweed)
Polycarpon tetraphyllum (fourleaf allseed)
Rosa multiflora (multiflora rose)
Rubus rosifolius (roseleaf raspberry)
Sanchezia parvibracteata (sanchezia)
Silene gallica (common catchfly)
Stenotaphrum secundatum (buffalo grass)
Tibouchina herbacea (cane tibouchina)

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.

IMG_5125

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.

New in August 2014 from the ISC

In August 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

Lepus europaeus (European hare) – the European hare has been widely introduced by humans from its original range in continental Europe and has successfully established populations in South Sweden, North and South America, Australia, New Zealand, Ireland and several Mediterranean and tropical islands. In its introduced range it can cause significant agricultural damage and compete or hybridise with native fauna. Conversely, populations have declined across much of its native range.

Lepus europaeus Invasive Species Compendium datasheet

Lepus europaeus Invasive Species Compendium datasheet

Myxobolus cerebralis (whirling disease agent) – this member of the parasitic myxozoan group causes whirling disease of salmon and trout, which causes fish to swim erratically, making feeding and avoiding predators difficult. M. cerebralis was first reported in Germany in the late 1890s, but, acting in cahoots with its invertebrate host, the sludge worm Tubifex tubifex, it has since spread throughout Europe. The international fish trade has helped it reach Africa, Lebanon, New Zealand and North America, where it may pose a risk to native fish species.

Ardisia crenata (coral berry) – native to east and southeast Asia, this evergreen shrub has introduced around the world and is widely cultivated as an ornamental plant. It invades forest margins and understory, where it can reduce light levels by 70%, thereby shading out native plants.

 

Other invasive species datasheets recently published include:

Alysicarpus vaginalis (alyce clover)

Caesalpinia pulcherrima (peacock flower)

Cortaderia jubata (purple pampas grass)

Juncus planifolius (broadleaf rush)

Lolium perenne (perennial ryegrass)

Melilotus albus (honey clover)

Mentha pulegium (pennyroyal)

Nasturtium microphyllum (one-row watercress)

Persicaria punctata (dotted smartweed)

Workshop held on future of Invasive Species Compendium

Members of the Invasive Species Consortium from the US, Mexico, Caribbean and South Pacific met in Washington DC on 4 August and unanimously agreed to keep the Invasive Species Compendium (ISC) an open access resource for a further five years. The ISC has been resourced by a diverse international consortium of government departments, development aid organizations and private companies. Consortium members agreed that work on the ISC to date was of global importance and utility, and should continue.

Invasive Species Compendium website

The Invasive Species Compendium website

The ISC is a global encyclopaedic resource that combines science-based information to support decision-making in invasive species management. Invasive species, such as non-native weeds, animals and microorganisms, are one of the main causes of biodiversity and economic loss worldwide, impacting livelihoods and human health. Since its launch, use of the ISC has continued to grow, now with over 400,000 users in 234 different countries. Read more of this post

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