Project overview
Ragwort is native to Eurasia. It is found across New Zealand where it invades pasture. It produces huge seed numbers that can spread by wind, water, soil movement, animals, humans and machinery.
Five agents have been released to attack ragwort: cinnabar moth (Tyria jacobaeae), ragwort flea beetle (Longitarsus jacobaeae), ragwort plume moth (Platyptilia isodactyla), ragwort seed fly (Botanophila jacaobaeae), and the ragwort crown-boring moth (Cochylis atricapitana) which is thought not to have established.
The ragwort seed fly is limited in its distribution and ineffective at limiting seed production. The cinnabar moth can contribute to ragwort control but tends to be patchy in its distribution and does not achieve damaging populations every year. The ragwort flea beetle is a highly effective agent which has successfully controlled ragwort throughout much of New Zealand, but not in high rainfall areas. The ragwort plume moth is now well established and reducing ragwort in areas where the flea beetle is not able to be effective.
