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.

Tutsan growing on sheep pasture in the Ruapheu District of the North Island, NZ; the copper colour arises from a reddening of the leaves as the plant matures (photo: Lizzie Rendell, 2011)

Tutsan growing on sheep pasture in the Ruapheu District of the North Island, NZ; the copper colour arises from a reddening of the leaves as the plant matures (photo: Lizzie Rendell, 2011)

In 2007 the Tutsan Action Group (TAG) was initiated, formed of local farmers, farm consultants, regional council Pest Plant Officers and representatives from the governmental Department of Conservation to tackle the growing problem. As well as carrying out their own work to raise awareness of tutsan throughout the region, TAG approached Landcare Research to ask for help and in 2009 a biological control programme was established through support from the Ministry for Primary Industries Sustainable Farming Fund.

To date the programme has consisted of an international effort between Landcare Research New Zealand, CABI Switzerland and more recently, CABI UK. Surveys have been carried out in both the invasive and native ranges of the plant to assess the extent of current populations and to identify potential biological control agents. In recent European surveys, a leaf beetle (Chrysolina abchasica) and a tortricid moth (Lathronympha strigana) were identified as having the potential to become biocontrol agents for tutsan and are currently being reared for host range testing by Landcare Research, under quarantine conditions in Lincoln, New Zealand.

The tutsan rust fungus, Melampsora hypericorum was also evident in surveys, both in the native range and in New Zealand. This pathogen has been known to provide control for tutsan populations in Victoria, Australia. In the early 1990s a biological control programme was initiated in Victoria since tutsan was affecting 67,000 ha in the Otaway Ranges. This programme was soon abandoned as surveys revealed that the rust fungus had self-introduced and was already controlling tutsan populations in this region; by 1993, surveys discovered only one live tutsan seedling. In recent times, tutsan is considered to be an increasing problem in Victoria, with the level of control provided by the rust fungus is currently unknown. Melampsora hypericorum is thought to be acting as an effective biological control agent in some parts of New Zealand, for example on some populations of the South Island, but remains ineffective in the regions worst affected. Molecular studies were conducted to establish where tutsan was originally introduced into New Zealand from, and revealed that several introductions are likely to have occurred. Plants in New Zealand’s North Island are likely to have been introduced from Wales or Ireland, and plants in the South Island from the UK, France or Spain. Genetic analysis of both plant and fungal material has also revealed that different genotypes of both tutsan and the rust occur in different regions across New Zealand. The range of genetic variation gives rise to a complex plant-fungal relationship which is playing a major role in the susceptibility of tutsan populations to M. hypericorum.

Current work at CABI, is focusing on assessing the virulence of 14 different strains of M. hypericorum collected from Europe and Georgia towards tutsan plants from New Zealand. Studies aim to find a strain that is more virulent towards the most problematic plant populations of tutsan that are not currently controlled by the rust. To date, the virulence of two strains of M. hypericorum have been assessed. A strain from Georgia failed to infect tutsan populations that are considered most problematic from the North Island. A strain collected from Pembrokeshire, Wales has produced a reliable infection on tutsan plants collected from four different New Zealand populations, including two populations which were ranked as having a high severity in 2011 surveys. Assessment of the remaining 12 rust isolates is currently ongoing.

Since little is currently known about M. hypericorum, trials are also being carried out to assess the infection parameters of the rust fungus. Free water availability and temperature are being investigated to determine the range and peak of these parameters for the species.

Tutsan in inoculation trials at CABI, Egham infected with the tutsan rust fungus, Melampsora hypericorum (photo: Lizzie Rendell, 2014)

Tutsan in inoculation trials at CABI, Egham infected with the tutsan rust fungus, Melampsora hypericorum (photo: Lizzie Rendell, 2014)

Lizzie Rendell

 Scientific Support

Beware! Pests on the high seas

Originally posted on The Plantwise Blog:

Contributed by Roger Day, CABI

If you put all the shipping containers in the world end to end, the line would go round the world 5 times. So a problem with a very small proportion of them is still a pretty big problem.

One such problem is that when a container is being packed with cargo, pests can get in and hitch a free ride to another country. So in 2008, the 3rd Session of the Commission on Phytosanitary Measures (CPM3) directed an expert working group to start developing an international standard for “Minimizing pest movement by sea containers”.

When a sea container is being packed with cargo, pests can get in and hitch a free ride to another country which can create considerable problems. When a sea container is being packed with cargo, pests can get in and hitch a free ride to another country, creating considerable problems. Photo: http://www.europhoning.fr

CPM 5 (2010) directed that work on the topic was urgent, and a draft standard was produced, but at CPM7, after lengthy discussions late…

View original 127 more words

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 February 2015 from the ISC

In February 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

February

Furcraea foetida (Mauritius hemp) – native to Central America, this evergreen perennial has been introduced worldwide as an ornamental, for its fibre and for erosion control. However, F. foetida can grow up to three metres across, compete with surrounding vegetation and displace native plants, and as a result has become dominant on many tropical islands and atolls around the world.

Hypostomus plecostomus (suckermouth catfish) – as a popular ornamental fish, H. plecostomus has been introduced to the Americas, Asia and Europe from its native range in northern South America. But this armour-plated, egg-guarding, hypoxia-proof omnivore can quickly monopolise resources and inhibit other aquatic organisms. By building nests in river banks and sediment, the suckermouth catfish contributes to bank erosion and increased turbidity, with associated environmental and socioeconomic impacts.

Bythotrephes longimanus (spiny waterflea) – the invasion of the crustacean B. longimanus in the North America Great Lakes has resulted in a marked decline of both the density and diversity of many copepod zooplankton species, with long-lasting effects in invaded systems. It has also been responsible for a large-scale shift in the zooplankton community and competes directly with planktivorous fish for food.

Other invasive species datasheets recently published include:

Adenostoma fasciculatum (chamise)

Adiantum hispidulum (rosy maidenhair fern)

Belonesox belizanus (pike killifish)

Bromus hordeaceus (soft brome)

Buddleja asiatica (dog tail)

Desmodium incanum (creeping beggerweed)

Euphorbia hypericifolia (graceful spurge)

Hymenachne amplexicaulis (hymenachne)

Lepomis microlophus (redear sunfsh)

Mikania scandens (climbing hempvine)

Polistes dominulus (European paper wasp)

Salvelinus namaycush (lake trout)

Simosyrphus grandicornis (flower fly)

Tuta absoluta, a new invasive invading India

corinprattcabi:

Additional information about Tuta absoluta can be found on the CABI Invasive Species Compendium http://www.cabi.org/isc/datasheet/49260

Originally posted on The Plantwise Blog:

Tuta absoluta (commonly known as tomato leaf miner) is a devastating pest of tomato which originated from South America. It can breed between 10-12 generations a year and each female can lay upto 250-300 eggs in her life time.  This pest has been very quickly crossing borders and devastating tomato production in both protected and open fields. The infestation of this pest is also reported on other solanaceous crops like potato, aubergine and common beans. The pest has spread from South America to several parts of Europe, entire Africa and has now spread to India. This pest is observed for the first time infesting tomato crop in Maharashtra, India reported by Indian Council of Agricultural Research. It has a potential to cause up to 90% loss of yield and fruit quality under greenhouse and field conditions. Plants are damaged by larval stages by direct feeding on leaves, stems, buds, calyces, young fruit, or…

View original 75 more words

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)

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