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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 - PowerPoint PPT Presentation
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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• Most successful BC programme
BC agent removal trialInsecticide
Water
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
Objectives
• Compare host-tests predictions to real world
• Demonstrate significance of BC agents
• Implications for future programmes
Retrospective host-range tests
• Indigenous species not included in original tests
• 4 indigenous species– 2 endemic– 1 critically threatened
H. involutumNZAustralia
H. rubicundulum
NZ endemic
H. pusillumNZAustralia
We asked:
Would we have introduced St. John’s wort beetles
today?
Methods
• Laboratory host range testing• No-choice / choice arenas• Feeding • Development• Oviposition
Results
H. perforatum H. involutum H. pusillum
Day
s to
end
of l
arva
l sta
ge
0
10
20
30
40
50
60
H. perforatum H. involutum H. pusillum
% c
ompl
eted
dev
elop
men
t
0
20
40
60
80
100 C. hypericiC. quadrigemina
H. perforatum H. involutum H. pusillum H. rubicundulum H. androsaemum
Eggs
per
pla
nt
0
5
10
15
20
25
30
35
Groenteman et al., 2011. Biological Control
Larval development
H. perforatum H. involutum H. androsaemum
H. rubicundulum H. pusillum
In reality…
• Little evidence of damage to indigenous species
• Significant displacement? Yet to be determined
• Benefits of control - enormous
• 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
Global context
Implications
• Risk rejecting effective & safe agents
• Control goals?
• Implications of failure to control?
USDA ARS - European Biological Control Laboratory, Bugwood.org
St. John’s wort beetles success
