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

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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

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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

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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

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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

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o o n n n n n d d d d j j j j j f f f f m m m m

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mb

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ruit

/5 t

ree

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Litchis

Host switching behaviour

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o o n n n n n d d d d j j j j j f f f f m m m m

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Macadamia Litchis

Host switching behaviour

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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