Project overview
Hawkweeds are native to Europe. They are present across the country and invade agricultural areas, roadsides, forest margins, disturbed shrubland, tussockland, fernland and riverbeds, sometimes forming dense mats.
Five insects have been released to attack hawkweeds (Pilosella aurantiaca, P. caespitosa, P. officinarum, P. praealta and Hieracium lepidulum). These biocontrol agents are the hieracium gall midge (Macrolabis pilosellae), hieracium gall wasp (Aulacidea subterminalis), hieracium crown hover fly (Cheilosia psilophthalma), hieracium root hover fly (Cheilosia urbana) and hieracium plume moth (Oxyptilus pilosellae). Only the gall midge and the gall wasp are known to have established so far. New Zealand is the first country to use any of these agents, and it is too early to know what collective impact they will have on hawkweeds.
The self-introduced hieracium rust (Puccinia hieracii var. piloselloidarum) is now widespread throughout the country.
