Biocontrol introduction
Target pest: Tradescantia fluminensis (Commelinales: Commelinaceae), tradescantia, wandering willie, wandering jew
Agent introduced: Neolema ogloblini (Coleoptera: Chrysomelidae), tradescantia leaf beetle
Imported:
2007
Import source:
Brazil
Import notes:
Hill (2007) - beetles were collected from four localities in SE Brazil. Those obtained from Lages and Rio Novo (Santa Catarina) and North of Vacaria (Rio Grande do Sul) were merged to form a single population. Those obtained from Fazenda (Paraná) have been retained as a second population. These two populations have been maintained in containment by Landcare Research at Lincoln (EPA application NOC06013). There is no evidence to suggest that the host ranges or biological characteristics of these collections are sufficient to consider that they have significantly different sets of traits that would allow the differentiation of ecotypes.
Fowler (2021a) - Neolema ogloblini is native to south-eastern Brazil and north-eastern Argentina. It was first imported into New Zealand from Brazil for host range testing in 2007. Permission to release this beetle was granted by EPA towards the end of 2008, but releases did not begin until 2011 because of the need to clear the beetle of a gut parasite.
Released:
2011
Release details:
Released in autumn 2011. 2,400 adults were released at 8 sites in the North Island.
Fowler et al. (2013) - since 2011 9,755 N. ogloblini have been released at 47 sites.
Landcare Research (2015a) - beetles collected from Kerikeri site where the population has exploded and released at other sites where the weed is a problem.
Landcare Research (2015j) - 13 releases 2014/2015.
Landcare Research (2016c) - Northland and Taranaki Regional Councils harvesting beetles from initial release sites to spread around their regions. Wellington Botanic Gardens are breeding the beetles to release in Wellington's parks and reserves; first release made at Mt Victoria.
Landcare Research (2018h, 2019j, 2021e) - 10 releases made in the year Sep 2017 - Aug 2018, 17 in the year Sep 2018 - Aug 2019, two in the year Sep 2020 - Aug 2021.
Establishment:
Fowler et al. (2013) - survival over the winter of 2011 has been confirmed.
Landcare Research (2014c) - appears to be establishing well at many sites.
Landcare Research (2018f) - the leaf beetle has established at all of the monitoring sites in the upper North Island, but appears to have failed to establish at monitoring sites set up in the Manawatū−Whanganui and Wellington regions. The leaf beetle can establish in these more southern localities, as it is doing well at a site in Palmerston North, so failure to establish at the southern monitoring sites might just be bad luck or indicate that getting establishment in cooler climate conditions is harder.
Fowler (2021a) - Neolema ogloblini is establishing well, particularly in northern regions.
Landcare Research (2022d) - the success of N. ogloblini has been highly variable in several regions of the country, with predation implicated in its failure to establish at some sites. Invasive common and German wasps (Vespula spp.), paper wasps (Polistes spp.), shield bugs, stink bugs and spiders are all suspected to be potential predators. In a trial to determine if predation is an important factor in the success of N. ogloblini, caged and uncaged releases were compared at nine sites in the Manawatu-Whanganui region: 78% of caged releases, but only 44% of uncaged released, established. However, there is no direct evidence that predation is limiting population growth in uncaged situations, and the greater success of the caged releases could be due to caging preventing dispersal of the released beetles and thus avoiding an Allee effect (a correlation between population density and fitness of a population). It is recommended N. ogloblini individuals are caged or confined for one generation after their release to increase the chance of establishment.
Landcare Research (2023g) - Neolema ogloblini has established well at many sites.
Impacts on target:
Landcare Research (2015a) - population has exploded at Kerikeri release site, where there is obvious plant damage.
Landcare Research (2016c) - the three beetle species introduced for this weed - Neolema abbreviata, N. ogloblini and Lema basicostata are establishing well and starting to knock back the plant at release sites. A trial has been established in forest remnants at Hikurangi flood plain (Northland) to assess tradescantia control and habitat recovery [see Clarkson et al. (2023) entry below].
Paynter et al. (2018) - outbreaks have caused extensive defoliation at some release sites.
Landcare Research (2018f) - at the Mt Smart, Whitford (both Auckland), Kerikeri and Maungatapere (both Northland) monitoring sites, tradescantia has now all but gone from some of the plots. Even in plots where the percentage cover is still quite high, the biomass has reduced considerably, and should now be low enough to allow native plants to establish.
Fowler (2021a) - extensive damage has already been seen at many release sites although there is some evidence that N. ogloblini is less abundant in riverine areas subject to flooding, and cooler sites further south. Neolema ogloblini should complement attack by the other biocontrol agents relealsed against T. fluminensis - the beetles Neolema abbreviata and Lema basicostata and the tradescantia yellow leaf spot fungus Kordyana brasiliensis.
Landcare Research (2021a) - all three beetle species released against T. fluminensis (N. ogloblini, Neolema abbreviata, Lema basicostata) have proven effective in controlling tradescantia in multiple regions, most notably Northland and the Waikato.
Landcare Research (2022d) - the success of N. ogloblini has been highly variable in several regions of the country [see Landcare Research (2022d) entry in 'Establishment' section].
Landcare Research (2023g) - Neolema ogloblini is causing major damage at many sites.
Clarkson et al. (2023) - a restoration field experiment in native forest remnants on the Hikurangi (Northland) floodplain, from 2016 to 2019, compared the effectiveness of biocontrol to manual clearing of T. fluminensis in reducing the weed's abundance and facilitating native plant regeneration. In the biocontrol treatment plots, the three beetle species that have been released against T. fluminensis - Neolema ogloblini, Lema basicostata, and Neolema abbreviata - were released together (the first such combined release of the three agents). After three years, plant species composition and T. fluminensis biomass were not statistically different between the biocontrol treatment and control (no treatment) plots, although mean T. fluminensis biomass was typically lower at biocontrol sites. The lack of significant biocontrol results is likely due to the short time span of the experiment, the large biomass of T. fluminensis present, low beetle population density, and cool, damp conditions (which do not favour these beetles) at most sites. Several more years would probably be required for beetle populations to increase and reduce T. fluminensis biomass sufficiently to facilitate survival of native seedlings.
Impacts on non-targets:
Hill (2007) - Tradescantia fluminensis belongs to the order Commelinales. There are no New Zealand native plants within that order; phylogenetically the closest native species appears to be nikau palm (Rhopalostylis sapida). Host range testing for Neolema ogloblini [NB: at the time of testing the species was misidentified as Lema obscura] by Landcare Research showed nikau was not a host; of the species tested only Tradescantia albiflora (in the same subgenus as T. fluminensis) was a good host. It is predicted that no native species will be at risk; N. ogloblini is specific to a small related group of plant species within the family Commelinaceae (and possibly within the genus Tradescantia).
Fowler et al. (2013) - Tradescantia albiflora appears to be a fundamental host. This plant is naturalised in New Zealand and a potential future weed. Potential 'spillover' attack on other plant species in the Commelinaceae maybe be beneficial as well as some are already naturalised in New Zealand and are invasive in other countries. New Zealand has no native or commercially significant exotic plants in this family.
Jackman et al. (2015) - glasshouse experiment with native plants kawakawa (Macropiper excelsum) and mahoe (Melicytus ramiflorus) suggests regeneration of native plants may benefit from damage to tradescantia caused by N. ogloblini feeding in the field.
Landcare Research (2018) - in some plots at the Mt Smart, Whitford (both Auckland), Kerikeri and Maungatapere (both Northland) monitoring sites, tradescantia has been replaced by a variety of natives.
General comments:
EPA (2007a), Hill (2007), EPA (2008) - beetles were imported as Lema sp. "tradescantia" nr guerini, subsequently misidentified as Neolema (=Lema) obscura, and finally determined to be Neolema ogloblini.
EPA Applications:
EPA (2007a) - 19 Jan 2007: application by Landcare Research to import into containment Lema sp. "tradescantia" nr guerini (Monrós) a biological control agent for Tradescantia fluminensis Vell. for host range testing and breeding purposes pending release approval. EPA Application # NOC06013, approved with controls 13 Feb 2007.
EPA (2008) - 14 Dec 2007: application by Auckland Regional Council to release from containment the beetle, Neolema ogloblini F. (Chrysomelidae), for the biological control of the weed tradescantia (Tradescantia fluminensis). EPA application # NOR07001, approved without controls 11 Apr 2008 (as Neolema (=Lema) obscura) and 22 Sep 2008 (as Neolema ogloblini). NB: The application was for N. obscura, but subsequent to the 11 April decision the Committee received new information from the applicant that the beetles in containment which formed the basis for the NOR07001 application had been misidentified and were not N. obscura but a closely related species, N. ogloblini. The application was to re-notified to allow submissions to be made under the new name N. ogloblini.
References
Clarkson BR, Cave VM, Bartlam S, Watts CH, Thornburrow D, Paynter Q (2023). Status of forest remnants invaded by tradescantia (Tradescantia fluminensis Vell.) following introduction of biocontrol beetles and manual clearance after three years. New Zealand Journal of Botany (published online 19 Nov 2023) https://doi.org/10.1080/0028825X.2023.2279297
EPA (2007a). EPA application NOC06013: to import into containment Lema sp. "tradescantia" nr guerini (Monrós) a biological control agent for Tradescantia fluminensis Vell. for host range testing and breeding purposes pending release approval. Environmental Protection Authority website https://www.epa.govt.nz/database-search/hsno-application-register/view/NOC06013
EPA (2008). EPA application NOR07001: to release from containment a beetle, Neolema ogloblini (Chrysomelidae), for the biological control of the weed tradescantia (Tradescantia fluminensis). Environmental Protection Authority website https://www.epa.govt.nz/database-search/hsno-application-register/view/NOR07001
Fowler S (2021a). Tradescantia leaf beetle: Neolema ogloblini. The Biological Control of Weeds Book - Te Whakapau Taru: A New Zealand Guide (Landcare Research) https://www.landcareresearch.co.nz/discover-our-research/biodiversity-biosecurity/weed-biocontrol/projects-agents/biocontrol-agents/tradescantia-leaf-beetle/
Fowler SV, Barreto R, Dodd S, Macedo DM, Paynter Q, Pedrosa-Macedo JH, Pereira OL, Peterson P, Smith L, Waipara N, Winks CJ and Forrester G (2013). Tradescantia fluminensis, an exotic weed affecting native forest regeneration in New Zealand: Ecological surveys, safety tests and releases of four biocontrol agents from Brazil. Biological Control 64: 323-329
Hill R. (2007). Application to release from containment the beetle, Lema obscura F. (Chrysomelidae), for the biological control of the weed tradescantia (Tradescantia fluminensis) # NOR07001. Environmental Protection Authority website https://www.epa.govt.nz/assets/FileAPI/hsno-ar/NOR07001/6e75e7c0b9/NOR07001.pdf
Jackman SD, Peterson PG, Robertson AW and van Koten C (2015). Neolema ogloblini: exploring a new option for the control of tradescantia (Tradescantia fluminensis) New Zealand Plant Protection 68: 187-192
Landcare Research (2014c). Who's who in biocontrol of weeds? What's new in biological control of weeds? 69: 10-11 https://www.landcareresearch.co.nz/assets/Publications/Weed-biocontrol/WhatsNew69.pdf
Landcare Research (2015a). Tradescantia beetles make big impression. What's new in biological control of weeds? 72: 2-3 http://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/issue-72
Landcare Research (2015j). Biocontrol agents released in 2014/15. Weed Biocontrol: What's New? 73: 2 http://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/issue-73
Landcare Research (2016c). Tradescantia beetles on the up. Weed Biocontrol: What's New? 76: 2 http://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/issue-76
Landcare Research (2018f). Tradescantia be gone! Weed Biocontrol: What's New? 84, May 2018 https://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/issue-84/tradescantia-be-gone
Landcare Research (2018h). Biocontrol agents released in 2017/18. Weed Biocontrol: What's New? 85, August 2018 https://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/issue-85/biocontrol-agents-released-in-201718
Landcare Research (2019j). Biocontrol agents released in 2018/19. Weed Biocontrol: What's New? 89, August 2019 https://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/weed-biocontrol-issue-89/biocontrol-agents-released-in-201819
Landcare Research (2021a). The more the merrier? Testing efficacy of multiple agents. Weed Biocontrol: What's New? 95, Feb 2021 https://www.landcareresearch.co.nz/publications/weed-biocontrol/weed-biocontrol-articles/the-more-the-merrier-testing-efficacy-of-multiple-agents
Landcare Research (2021e). Further reading and agents released. Weed Biocontrol: What's New? 97, August 2021 https://www.landcareresearch.co.nz/publications/weed-biocontrol/weed-biocontrol-articles/further-reading
Landcare Research (2022d). Predation and the tradescantia leaf beetle. Weed Biocontrol: What's New? 101, August 2022 https://www.landcareresearch.co.nz/publications/weed-biocontrol/weed-biocontrol-articles/predation-and-the-tradescantia-leaf-beetle/
Landcare Research (2023g). Who's who in the biological control of weeds. Weed Biocontrol: What's New? 105, August 2023 https://www.landcareresearch.co.nz/publications/weed-biocontrol/weed-biocontrol-articles/whos-who/
Paynter Q, Fowler SV, Groenteman R. (2018). Making weed biological control predictable, safer and more effective: perspectives from New Zealand. BioControl 63: 427–436 (first published online 8 Aug 2017) https://doi.org/10.1007/s10526-017-9837-5 https://link.springer.com/article/10.1007/s10526-017-9837-5
