Ragwort
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.
- pdf Comparing ragwort then with now: Part two - Issue 78, p.2-3 pdf File, 880 KB
- pdf Comparing ragwort then with now: Part one - Issue 77, p.4-5 pdf File, 850 KB
- pdf Farmer grateful for tiny beetle - Issue 76, p.8 pdf File, 759 KB
- pdf Ragwort biocontrol pays off - Issue 74, p.2-3 pdf File, 6.6 MB
- pdf West Coast ragwort control - a successful community project - Issue 66, p.2-3 pdf File, 855 KB