Biocontrol introduction
Target pest: Cirsium arvense (Asterales: Asteraceae), Californian thistle
Agent introduced: Puccinia punctiformis (Uredinales: Pucciniaceae), Californian thistle rust
Import notes:
Waipara et al. (2009) - P. punctiformis was first recorded in New Zealand as early as 1881.
Landcare Research (2014c) - self-introduced.
Released:
Accidental introduction, first recorded in New Zealand in 1881.
Establishment:
Waipara et al. (2009) - subsequent to its accidental introduction to New Zealand, P. punctiformis was used as an augmentative biocontrol agent against Cirsium arvense and a recent comparative survey has shown that this pathogen occurs in New Zealand at levels similar to its native range of Europe.
Landcare Research (2014c) - common.
Impacts on target:
Landcare Research (2014c) - damage not usually widespread.
Cripps et al. (2014) - a field trial at Lincoln, Canterbury, applying P. punctiformis-infected leaf debris to C. arvense autumnal rosettes in autumn 2012 resulted in an average 15% decline in thistle shoot density in treated plots compared to non-inoculated plots over five assessments from spring 2012 and spring 2013. However, the reduction in shoot density was significantly different from zero at only one assessment time. This effective technique for initiating systemic rust disease should be applied at a broader scale to test the impact on C. arvense populations.
Kentjens et al. (2023) - it seems that C. arvense is unselective in the fungal species it allows to colonise and its endophytic populations [fungi that live inside the plant] are a function of location. Endophytes can alter outcomes of a host-pathogen interaction; they can interact with a pathogen directly or induce resistance in the host. Puccinia punctiformis performs inconsistently on C. arvense as a biocontrol agent. Problems with P. punctiformis establishment and control of C. arvense may be attributable to differing plant endophytic populations in various environments.
Kentjens et al. (2025) - a study at Lincoln, Canterbury, showed fungal endophytic communities in C. arvense were more stable (in terms of species diversity) over a growing season in stems than in leaves and roots. This finding could be significant with respect to microbial biocontrol agents such as P. punctiformis, as most research has focussed on biocontrol agents infecting through leaves or roots. P. punctiformis performs inconsistently as a classical biocontrol agent but could be more consistent infecting stems with more stable endophyte communities. Mowing could expose stems to pathogenic agents, either naturally occurring or through controlled applications, potentially leading to large declines in C. arvense populations, as shown by trials overseas.
Impacts on non-targets:
Waipara et al. (2009) - to assess non-target impacts of pathogenic weed biocontrol agents, including Puccinia punctiformis, introduced to New Zealand, nationwide surveys were conducted 2000-2009, focussing on plants closely related to the target weeds. No non-target damage was observed for P. punctiformis, despite positive infection being observed on many of the host (target) plants at the same sites.
References
Cripps M, Bourdot G, Saville D, Berner D (2014). Success with the rust pathogen, Puccinia punctiformis, for biological control of Cirsium arvense. Proceedings of the XIV International Symposium on Biological Control of Weeds, Kruger National Park, South Africa, 2-7 March 2014
Kentjens W, Casonato S, Kaiser C (2023). Californian thistle (Cirsium arvense): endophytes and Puccinia punctiformis. Pest Management Science, 2023, Jan 29 https://onlinelibrary.wiley.com/doi/full/10.1002/ps.7387
Kentjens W, Casonato S, Kaiser C (2025). Endophytic diversity and community composition of Cirsium arvense tissues over a growing season. European Journal of Plant Pathology 173: 505-521 https://doi.org/10.1007/s10658-025-03071-8
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
Waipara NW, Barton J, Smith LA, Harman HM, Winks CJ, Massey B, Wilkie JP, Gianotti AF, Cripps MG (2009). Safety in New Zealand weed biocontrol: a nationwide pathogen survey for impacts on non-target plants. New Zealand Plant Protection 62: 41-49 https://journal.nzpps.org/index.php/nzpp/article/view/4804/4632
