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St. John’s wort beetles would not have been introduced to NZ today!

St. John’s wort beetles would not have been introduced to NZ today!. Ronny Groenteman, Simon Fowler & Jon Sullivan. St. John’s Who???. St. John’s wort Hypericum perforatum. Introduced as medicinal herb Severe pasture weed by 1930s Toxic to live stock Programme started 1943

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St. John’s wort beetles would not have been introduced to NZ today!

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  1. St. John’s wort beetles would not have been introduced to NZ today! Ronny Groenteman, Simon Fowler & Jon Sullivan

  2. St. John’s Who???

  3. St. John’s wortHypericumperforatum • Introduced as medicinal herb • Severe pasture weed by 1930s • Toxic to live stock • Programme started 1943 • Most successful BC programme

  4. BC agent removal trial Insecticide Water

  5. St. John’s wort biocontrol • Why invest funds in an old successful programme??? • Post-release studies are pivotal to advance BC practice: • Safety • Effectiveness • Economics

  6. Objectives • Compare host-tests predictions to real world • Demonstrate significance of BC agents • Implications for future programmes

  7. Retrospective host-range tests • Indigenous species not included in original tests • 4 indigenous species • 2 endemic • 1 critically threatened

  8. H. involutum NZ Australia

  9. H. rubicundulum NZ endemic

  10. H. pusillum NZ Australia

  11. We asked: Would we have introduced St. John’s wort beetles today?

  12. Methods • Laboratory host range testing • No-choice / choice arenas • Feeding • Development • Oviposition

  13. 60 35 30 50 25 40 20 Days to end of larval stage Eggs per plant 30 15 20 10 10 5 0 0 H. perforatum H. involutum H. pusillum H. perforatum H. involutum H. pusillum H. rubicundulum H. androsaemum Results C. hyperici C. quadrigemina 100 80 60 % completed development 40 20 0 H. perforatum H. involutum H. pusillum Groenteman et al., 2011. Biological Control

  14. Larval development H. perforatum H. involutum H. androsaemum H. rubicundulum H. pusillum

  15. In reality… • Little evidence of damage to indigenous species • Significant displacement? Yet to be determined • Benefits of control - enormous

  16. Global context • Recent review of successful programmes in N. America concluded: • St. John’s wort beetles would not have been introduced nowadays • More stringent regulations / interpretation of old regulations • Monitoring crucial for data-driven benefit-risk decisions

  17. Implications • Risk rejecting effective & safe agents • Control goals? • Implications of failure to control?

  18. St. John’s wort beetles success USDA ARS - European Biological Control Laboratory, Bugwood.org

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