Target pest: Hieracium spp. (Asterales: Asteraceae), hawkweed
Agent introduced: Puccinia hieracii var. piloselloidarum (Uredinales: Pucciniaceae), hieracium rust
Pre -1995 and later
Smith (2011) - first noticed in 1995 on plants collected from Molesworth Station. It is not known how it originally arrived in New Zealand. Subsequently two further strains from Ireland were released.
Smith (2011) - occurs throughout the Hieracium infested parts of the country.
Landcare Research (2014c) - common.
Impacts on target:
Landcare Research (2014c) - causes slight damage to some mouse-ear hawkweed; plants vary in susceptibility.
Impacts on non-targets:
Waipara et al. (2009) - to assess non-target impacts of pathogenic weed biocontrol agents, including Puccinia hieracii var. piloselloidarum, 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. hieracii var. piloselloidarum, despite positive infection being observed on many of the host (target) plants at the same sites.
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
Smith L (2011). Hieracium Rust. In The Biological Control of weeds Book (Landcare Research) http://www.landcareresearch.co.nz/research/biocons/weeds/book/documents/Hieracium_Rust.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