Crop protection integrated control of macadamia pests in south africa with specific emphasis on...
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Transcript of Crop protection integrated control of macadamia pests in south africa with specific emphasis on...
Integrated control of macadamia pests in South Africa with specific
emphasis on stink bugs
Schalk Schoeman
Introduction
• Understand the problem • Difficult to monitor for the stinkbugs (no
pheromones!!) • Low tolerance for damage • Bugs migrate between various crops as well as wild
hosts • Most chemicals really only work for a few days • Integrate/coordinate control between a number of
crops. • Website regarding macadamia monitoring a beginning
but more is needed
Materials and methods
• Monitoring with branch shaking method since the spring of 2010
• Nut dissection during the early part of the season
• Pheromones for the tortricid complex
• Quantification of eggs, larvae as well as damage up to physiological maturity
• Two localities – unsprayed mixed cultivar orchards
Relative seasonal abundance - Nelspruit
0
5
10
15
20
25
30
35
40
n d j j f m m a a m m j j j j a s s o o n n d d j j f f m m a a m
Tota
l nu
mb
er
of
stin
kbu
gs/1
0 t
ree
s
2011 2010 2012
Relative seasonal abundance - Friedenheim
2011 2012
Overwintering/diapause of the two spotted bug - Nelspruit
2010
Overwintering/diapause of the two spotted bug - Friedenheim
Seasonal succession of indigenous stinkbugs at Nelspruit
0
20
40
60
80
100
120
n d j j f m m a a m m j j j j a s s o o n n d d j j f f m m a a m m j j j j
Pe
rce
nta
ge
Two spotted bug Other pentatomid bugs 2012 2010
Seasonal succession of indigenous stinkbugs at Friedenheim
0
20
40
60
80
100
120
o o n n n n d d d j j j j f f f f f m m m m a a a m m m m m j j j j j j a
Pe
rce
nta
ge
Weeks
Two spotted bug Other pentatomid bugs 2011 2012
Relative seasonal abundance of the coconut bug
2011 2012
0
10
20
30
40
50
60
70
80
o o n n n n n d d d d j j j j j f f f f m m m m
Nu
mb
er
of
dam
age
d f
ruit
/5 t
ree
s
Litchis
Host switching behaviour
0
10
20
30
40
50
60
70
80
o o n n n n n d d d d j j j j j f f f f m m m m
Nu
mb
er
of
dam
age
d f
ruit
/5 t
ree
s
Macadamia Litchis
Host switching behaviour
0
20
40
60
80
100
120
140
o o n n n n n d d d d j j j j j f f f f m m m m
Nu
mb
er
of
dam
age
d f
ruit
/5 t
ree
s
Avocado Macadamia Litchis
Host switching behaviour
Summary of insect ecology in the orchard
Summary of insect ecology in the orchard
Summary of insect ecology in the orchard
Summary of insect ecology in the orchard
Summary of insect ecology in the orchard
Summary of insect ecology in the orchard
Summary of insect ecology in the orchard
Summary of insect ecology in the orchard
Summary of insect ecology in the orchard
Summary of insect ecology in the orchard
Proposed spraying dates
Proposed spraying dates
Proposed spraying dates
Proposed spraying dates
Proposed spraying dates
Relative abundance of nut borers and related damage
Relationship between pheromone trap catches and various nut borer stages
Regression coefficient (r2)
Eggs Larvae Damage
Ne
lsp
ruit
Eggs
Larvae 0.372
Damage 0.864 0.399
Moths 0.588 0.277 0.47
Frie
de
nh
eim
Eggs
Larvae -0.453
Damage 0.676 -0.421
Moths -0.641 0.451 -0.488
Relative seasonal abundance of nut borer moths in relation to damage - Nelspruit
Relative seasonal abundance of nut borer moths in relation to damage - Friedenheim
Conclusions • Summer peak of two spotted bug ± 1220 degree days
• Autumn peak of two spotted bug ± 2220 less well defined
• Coconut bug is important !! – check for fallen nuts during December
• Two spotted bug overwinter as adults and nymphs
• Very low population levels during early summer – only adults
• Other bugs migrate into macadamia orchards during winter but don’t breed.
• Moths migrate into mac orchards ± 9 weeks after full bloom.
• Mating and oviposition takes place soon afterwards
• Best time for spraying a contact insecticide - ± 2 weeks after peak moth flights are recorded during Nov/Dec
• Scouting for both complexes will be available on a website before the new season.
• Website will be updated weekly
• Initially Nelspruit area but Levubu and KZN will be added through the season
Acknowledgements
• Subtrop
• Members of the stink bug working group and particularly Gerhard Nortje
• ARC-ITSC
• Colleen Hepburn
• Prof. Ben Botha