1. 0.000
0.025
0.050
0.075
201511 201512 201601 201602 201603
Abundancepershoot
Life stage Total larvae early instar mid instar late instar prepupae adult
0.0
0.2
0.4
0.6
201511 201512 201601 201602 201603
Abundancepershoot
Life stage total larvae early instar mid instar late instar
0.00
0.05
0.10
0.15
201511 201512 201601 201602 201603
Abundancepershoot
Life stage eggbatch early instar mid instar late instar
0.00
0.25
0.50
0.75
1.00
201511 201512 201601 201602 201603
Abundancepershoot
Life stage eggbatch 1st instar 2nd instar 3rd instar 4th instar adult
Huimin Lin, Dr. Tara Murray & Prof. Euan Mason
School of Forestry, University of Canterbury, Christchurch, New Zealand
Population Dynamics of Four Insect Defoliators in a
Dryland South Island Eucalyptus plantation
62
64
66
68
70
72
0
5
10
15
20
25
30
35
201511 201512 201601 201602 201603
Humidity(%rh)
Temperature(°C)
mean temp. mean max. temp. mean min. temp. humidity
Why
New Eucalyptus species (Eucalyptus bosistoana)
being considered for emerging ground durable
eucalypt industry. Information required for
future modelling to help predict and manage
insect pests outbreaks.
What
Monitored population dynamics of two
significant leaf chewers (beetle and moth), a leaf
mining sawfly that damages older foliage, and a
leaf rolling moth that damages new shoots.
Where and When
• 0.8 ha 5-year old E. bosistoana plantation
• Seddon, Marlborough, South Island
• November 2015 – March 2016
How
• 229 trees, 3-5 shoots per trees depending on
tree size
• Counted number of each life stage of each
species on each shoot
• Monitored temperature and humidity using
digital loggers
R² = 0.7754 R² = 0.7431
R² = 0.8222
0
0.2
0.4
0.6
0.8
15 17 19 21 23 25 27 29 31 33
Abundancepershoot
Temperature (°C)
S. macropetanavs mean temp. S. macropetanavs max. temp. P. froggattivs max. temp.
Paropsis charybdis
• One generation observed
• Adult peaked in December / January
• Disappeared in March.
Opodiphthera eucalyti
• Two distinct generations observed
• Larval populations peaked in
December and February / March.
Phylacteophaga froggatti
• Most larvae were found after December
• Relatively low populations throughout
the monitoring period.
Strepsicrates macropetana
• Multiple overlapping generations
• Larval populations peaked in February.
Total larval number of S.mecropetana had a strong linear correlation with mean and mean maximum
temperature, and P. froggatti had a strong polynomial correlation with mean maximum temperature.
• Observation of P. charybdis is different from North Island & Australian studies in which two generations are often observed. This is
likely due to local environmental conditions which were notably dry during this particular monitoring season.
• Observations of other species do not conflict substantially with limited studies of previous observations from North Island or Australia.
• Impacts of defoliation by P. charybdis and O. eucalypti on E. bosistoana growth are also being assessed.
Nov Dec Jan Feb Mar
Nov Dec Jan Feb Mar
Nov Dec Jan Feb Mar
Nov Dec Jan Feb Mar
Abundancepershoot(±SE)Abundancepershoot(±SE)
0.05
0.00
0.15
0.10
Life stage: eggbatch early instar mid instar late instar
Abundancepershoot(±SE)Abundancepershoot(±SE)
1.00
0.75
0.50
0.25
0.00
Nov Dec Jan Feb Mar
0.4
0.2
0.0
0.6
Life stage: total larvae early instar mid instar late instar
Lifestage: totallarvae earlyinstar mid instar lateinstar prepupae adult
0.075
0.050
0.025
0.000
Conclusion
Life stage: eggbatch 1st instar 2nd instar 3rd instar 4th instar adult