Biocontrol introduction
Target pest: Cirsium arvense (Asterales: Asteraceae), Californian thistle
Agent introduced: Lema cyanella (Coleoptera: Chrysomelidae), Californian thistle leaf beetle
Imported:
1981, 1990
Import source:
Canada
Import notes:
Cameron et al. (1989) - one hundred adults were received from Regina Station of Agriculture Canada in June 1981, and reared for three generations in quarantine prior to release.
Hayes (2007b) - Lema cyanella is native to Europe and Asia, but they are quite rare, possibly because of high levels of parasitism. The beetles were first imported into New Zealand from Canada in 1981. Parasite-free progeny from this importation were released into a field cage in 1983 but failed to prosper. A second importation was made in 1990 and the beetles were successfully mass-reared for release.
Released:
1983 (from 1981 importation), 1990's (from 1990 importation)
Release details:
Cameron et al. (1989) - one release from the 1981 importation was made in 1983 in a field cage at Winchmore (Mid Canterbury).
Hayes (2007b) - released widely throughout New Zealand from the 1990 importation.
Establishment:
Cameron et al. (1989) - the 1983 release did not establish. An extended period of artificial rearing (10 generations) in quarantine in Canada prior to importation, and another three generations and rephasing in quarantine in New Zealand prior to release probably destroyed all chances of environmental adaptation and eventual establishment.
Harman et al. (1996) - has established in Canterbury from the 1990s releases.
Hayes (2007a, 2007b) - the beetles are thought to have survived at one site only near Auckland from the releases in the 1990s, though numbers there remain low.
Cripps et al. (2011) - has established at just one site in northern New Zealand where it has only recently become common after remaining almost undetectably rare at this site for about 15 years.
Landcare Research (2017g) - only established at one site near Auckland from which it is dispersing.
Landcare Research (2019i) - possibly also established at one site in the Hawke's Bay.
Gourlay (2021f) - establishment success was disappointing, with L. cyanella thought to have only survived at one site near Auckland. More recently the beetles have been seen in the Hawke’s Bay, and it seems more likely that they also established here rather than subsequently dispersed from further north.
Impacts on target:
Hayes (2007b) - can cause heavy damage when kept on caged plants, but in the field the level of damage appears inconsequential to the plant.
Landcare Research (2015i) - causes obvious damage at the one site (near Auckland) where it is established.
Gourlay (2021f) - adult and larval feeding can be conspicuously damaging but, for unknown reasons, populations appear to be highly localised.
Paynter (2024) - factors influencing the success of weed biocontrol agents released and established in New Zealand were investigated. Each agent’s impact on the target weed in New Zealand was assessed as ‘heavy’, ‘medium’, ‘variable’, ‘slight’ or ‘none’, where a ‘heavy’, ‘medium’ or ‘variable’ impact have all been observed to reduce populations or percentage cover of their target weed in all or part of their respective target weed ranges in New Zealand. Results showed that: (i) agents that are highly damaging in their native range were almost invariably highly damaging in New Zealand; (ii) invertebrate agents with a closely related ‘native analogue’ species are susceptible to parasitism by the parasitoids that attack their native analogues and failed to have an impact on the target weed, and (iii) agent feeding guild helped predict agent impact - in particular, agents that only attack reproductive parts of the plant (e.g., seed and flower-feeders) are unlikely to reduce weed populations. Damaging impacts of L. cyanella, a defoliating beetle, have not been reported in its native range (where it is typically rare), it does not have a New Zealand native ecological analogue and its impact in New Zealand is assessed as ‘slight’.
Impacts on non-targets:
Hayes (2007b) - extremely unlikely to attack plants other than Californian thistle, and possibly Scotch thistle (Cirsium vulgare), nodding thistle (Carduus nutans) and variegated thistle (Silybum marianum) to a lesser extent.
Cripps et al. (2011) - the host range of L. cyanella species is confined to species of Cirsium, Carduus and Silybum. New Zealand has no native plants in the tribe (Cardueae, commonly known as thistles) to which these genera belong.
Paynter et al. (2015) - surveys of the potential non-target host Carduus nutans (nodding thistle) show this plant (an exotic weed) is a 'full' host (can support breeding populations).
References
Cameron PJ, Hill RL, Bain J, Thomas WP (1989). A Review of Biological Control of Invertebrate Pests and Weeds in New Zealand 1874-1987. Technical Communication No 10. CAB International Institute of Biological Control. DSIR Entomology Division. 424p.
Cripps MG, Gassmann A, Fowler SV, Bourdôt GW, McClay AS, Edwards GR. (2011). Classical biological control of Cirsium arvense: Lessons from the past. Biological Control 57: 165–174
Gourlay H (2021f). Californian thistle leaf beetle: Lema cyanella. The Biological Control of Weeds Book - Te Whakapau Taru: A New Zealand Guide (Landcare Research) [Update of Hayes (2007b] https://www.landcareresearch.co.nz/discover-our-research/biodiversity-biosecurity/weed-biocontrol/projects-agents/biocontrol-agents/californian-thistle-leaf-beetle/
Harman HM, Syrett P, Hill RL, Jessep CT. (1996). Arthropod introductions for biological control of weeds in New Zealand, 1929 - 1995. New Zealand Entomologist, 19(1): 71-80
Hayes L (2007a). Status of weed biocontrol agents in Southland. A report prepared for Environment Southland Sept 2007. Landcare Research Contract Report: LC0708/022
Hayes L (2007b). Californian thistle leaf beetle: Lema cyanella. The Biological Control of Weeds Book - Te Whakapau Taru: A New Zealand Guide (Landcare Research) [Updated 2021 - see Gourlay (2021f)] https://www.landcareresearch.co.nz/discover-our-research/biodiversity-biosecurity/weed-biocontrol/projects-agents/biocontrol-agents/californian-thistle-leaf-beetle/
Landcare Research (2015i). Who's who in biological control of weeds? Weed Biocontrol: What's New? 73: 10-11 http://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/issue-73
Landcare Research (2017g). Who's who in biological control of weeds? Weed Biocontrol: What's New? 81: 10-11 https://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/issue-81
Landcare Research (2019i). Who's who in biological control of weeds? Weed Biocontrol: What's New? 89, August 2019 https://www.landcareresearch.co.nz/publications/newsletters/biological-control-of-weeds/weed-biocontrol-issue-89/whos-who-in-biological-control-of-weeds
Paynter Q (2024). Prioritizing candidate agents for the biological control of weeds. Biological Control, Volume 188, January 2024, Article Number 105396 https://doi.org/10.1016/j.biocontrol.2023.105396
Paynter QE, Fowler SV, Gourlay AH, Peterson PG, Smith LA and Winks CJ (2015). Relative performance on test and target plants in laboratory tests predicts the risk of non-target attack in the field for arthropod weed biocontrol agents. Biological Control 80: 133-142 https://doi.org/10.1016/j.biocontrol.2014.10.007
