Contents

Preface

List of Contributors

1. Taxonomic Issues

Introduction

Interpreting variation in aphids

The taxonomy of pest aphids – what's in a name?

The 14 aphid species of most agricultural importance

Acyrthosiphon pisum (pea aphid)

Aphis craccivora (cowpea aphid)

Aphis fabae (black bean aphid)

Aphis gossypii (cotton or melon aphid)

Aphis spiraecola (green citrus aphid or spiraea aphid)

Diuraphis noxia (Russian wheat aphid)

Lipaphis pseudobrassicae (mustard aphid)

Macrosiphum euphorbiae (potato aphid)

Myzus persicae (peach–potato aphid)

Rhopalosiphum maidis (corn leaf aphid)

Rhopalosiphum padi (bird cherry–oat aphid)

Schizaphis graminum (greenbug)

Sitobion avenae (grain aphid)

Therioaphis trifolii (spotted alfalfa and yellow clover aphids)

Conclusions

References

2. Population Genetic Issues: The Unfolding Story Using Molecular Markers

Introduction

Application of molecular markers in aphidology

Detection of genetic variation

Molecular phylogenetics and karyotypes

Clonal studies

Life cycle

Adaptation to host plants

Insecticide resistance

Pathogenicity

Dispersal and geographic range

Geographic colonization

Conclusions

Acknowledgements

References

3. Life Cycles and Polymorphism

Introduction

Types of life cycle

Host-alternating aphids

Non-host-alternating aphids

Two-year life cycles

Holocyclic and anholocyclic life cycles

Factors determining the production of different morphs

Determination of sexual morphs

Determination of asexual winged morphs

Diapausing morphs

Colour polymorphism

The importance of different morphs for crop protection

Pest status

Virus transmission

Forecasting

The importance of polymorphism in determining pest status

Conclusions

References

4. Host-plant Selection and Feeding

Introduction

Orientation and host-plant finding

Visual responses

Olfactory responses

Plant contact after landing

Plant penetration and feeding

Pathway phase

Phloem phase

Phloem feeding

Xylem drinking

Leaving a plant

Plant responses and predisposition to aphid feeding

Aphids and host plants – a challenging research field

Conclusions

References

5. Nutrition and Symbiosis

Introduction

Microbial symbiosis in aphids

Diversity of microorganisms

Location of symbiotic microorganisms

Acquisition of symbiotic microorganisms

Significance of symbiotic microorganisms to aphids

Carbon nutrition

Sugars

Lipids

Nitrogen nutrition

Amino acids and their sources

The fate of amino acids in aphids

Other dietary sources of nitrogen

Minerals and micronutrients

Artificial diet

History of artificial diets for aphids

Recipe for the diet and practical procedures

Relation between the diet and plant phloem sap

Aphid performance on the diet

How useful is the diet for studies on aphid nutrition?

Conclusions and future prospects

Acknowledgements

References

6. Growth and Development

Introduction

Definitions

Uses of aphid growth and developmental rates

Measurement of aphid growth and development rates

Growth rates

Developmental rates

The intrinsic rate of increase, Γ[sub(m)]

Experimental techniques

Aphid cages

Disadvantages of aphid cages

Factors affecting aphid growth and development

Factors affecting the reliability of size x fecundity relationships

Difference between nymphs destined to be apterous and alate

Temperature

Population-scale factors

Conclusions

References

7. Aphid Movement: Process and Consequences

Introduction

Pest status

The nature of aphid movement

Conceptual framework for aphid movement

Modes of transport

Scales of displacement

Aphid life stages, morphs and active modes of transport

The migratory process

Events leading to take-off

Take-off and ascent

Horizontal translocation

Switching off the migratory urge

Appetitive dispersal

Stimuli that cause aphids to disperse in an appetitive manner

Response to multiple perturbations

Landing and alighting cues

Incorporating aphid movement into Pest Management strategies

Components of IPM programmes

Categories of aphids as agricultural pests

Conclusions

Acknowledgments

References

8. Predators, Parasitoids and Pathogens

Introduction

Predators

Coccinellidae (ladybird beetles)

Syrphidae (hover flies)

Chrysopidae and Hemerobiidae (lacewings)

Cecidomyiidae (predatory midges)

Other arthropod predators

Parasitoids

General biology

Foraging behaviour and host finding

Patterns of resource use

Aphid pathogens

Biology of entomophthoralean fungi

Epizootiology of entomophthoralean fungi

Intraguild interactions, mutualistic ants and aphid symbionts

Intraguild predation and competition

The effects of mutualistic interactions with ants on predation and parasitism

Aphid symbionts and resistance to parasitism

Conclusions

References

9. Chemical Ecology

Introduction

Methods

Interactions between aphids

Sex pheromones

Alarm pheromones

Social interactions: aggregation, density regulation and avoidance

Interaction with plants

Host-plant semiochemicals

Non-host-plant semiochemicals

Aphid effects on the plant

Interaction with natural enemies

Responses of natural enemies to aphid-produced chemicals

Responses of natural enemies to aphid-induced plant signals

Conclusions

References

10. Insecticide Resistance

Introduction

Diagnosis of resistance in aphids

Relevance of bioassays to field control

Biochemistry and molecular basis of resistance

Resistance mechanisms in Myzus persicae (peach–potato aphid)

Resistance mechanisms in other aphid species

Neonicotinoid resistance

Factors affecting the dynamics of insecticide resistance in the field

Selection pressures

Ecological factors

Pleiotropic effects of resistance

Aphids in which resistance poses a minor or potential threat

Conclusions

Acknowledgements

References

11. Coping with Stress

Introduction

Plant factors

Nutritional stress

Non-nutritional plant factors

How aphids cope with nutritional stress

Temperature stresses

Effects of temperature on development, reproduction and movement

Cold Stress

Coping with cold

Heat stress

A molecular approach to understanding aphid responses to stress

Conclusions

References

12. Population Dynamics

Introduction

Biological background

Aphid biology relevant to population dynamics

Biology of natural enemies relevant to aphid population dynamics

Theory of aphid population dynamics

Features of aphid population dynamics that should be incorporated in models

Regression model

Regression model with stochasticity

Logistic model with variable 'carrying capacity'

Cumulative density model

Logistic model with variable carrying capacity and growth rate affected by cumulative density

Comparison of the different population models

Natural enemies and aphid abundance

Practical problems

Field estimates of abundance and population growth rate

Trap estimates of abundance

Consequences for pest management

Conclusions

References

13. Feeding Injury

Introduction

Injury classification

Asymptomatic injury

Symptomatic injury

Aetiological agents in Aphidoidea saliva

The biochemical and physiological bases for symptoms of injury

Basis of asymptomatic injury

Basis of symptomatic injury

Ecological modulation of aphid injury

Abiotic factors

Biotic factors

Ramifications of aphid injury research for crop protection

Conclusions on research frontiers in the understanding of injury from aphid feeding

References

14. Transmission of Plant Viruses

Introduction

Virus–vector interactions

Aphids as effective virus vectors

Host selection related to virus acquisition and inoculation

Transmission modes of plant viruses by aphids

Non-persistent transmission

Semi-persistent transmission

Persistent transmission

Epidemiology

Biological factors

Cultural practices

Weather

Disease forecasting

Disease management strategies

Use of genotypes resistant to the virus and/or to the aphid vectors

Elimination of virus sources

Prevention or reduction of virus spread

Conclusions

Acknowledgements

References

15. Chemical Control

Introduction

Choice of aphicide

Modes of action

Organophosphates and carbamates

Pyrethroids

Neonicotinoids

Pymetrozine

Diafenthiuron

Triazamate

Adjuvants and synergists

Application

Thresholds for control

Wheat and barley

Pea

Field bean

Brassicas

Cotton

Sugar beet

Top fruit

Efficacy

Poaceae

Soft Fruit

Top fruit

Solanaceae

Chenopodiaceae

Leguminosae

Brassicas

Lettuce

Other vegetables

Malvaceae

Others

Conclusions

References

16. Cultural Control

Introduction

Overview

Mulches

Row covers

Particle films

Sowing and planting date

Plant density

Crop-plant pruning

Irrigation and fertilizer management

Intercropping, living mulches and cover crops

Trap crops

Provision of resources for natural enemies

Provision of refuges for natural enemies

Conclusions

References

17. Host-plant Resistance

Introduction

Types of host-plant resistance to aphids

Antixenosis

Antibiosis

Tolerance

What is the preferred type of resistance?

Mechanisms of host-plant resistance to aphids

Mechanisms of antixenosis

Mechansims of antibiosis

Mechanisms of tolerance

Further considerations

Yield drag or other fitness costs

Negative effects on natural enemies

Problem trading

Biotypes

Spread of virus

Interactions with other control measures

Conclusions

Acknowledgments

References

18. Biological Control

Introduction

Parasitoids

Cereal aphids

Legume aphids

Aphids on orchard crops

Banana aphids

Aphids on forest and urban trees

Glasshouse aphids

Aphidoletes aphidimyza (predatory gall midge)

Glasshouse aphids

Aphids on field and orchard crops

Coccinellidae (ladybird beetles)

Glasshouse aphids

Aphids on field crops and amenity plants

Aphids on orchard crops

Lacewings

Glasshouse aphids

Aphids on field crops and amenity plants

Aphids on orchard crops and tree seedlings

Syrphidae (hover flies)

Entomopathogenic fungi

Glasshouse aphids

Aphids on field crops

Cotton aphids

Aphids in orchards

Aphids on vegetables

Conclusions

References

19. Monitoring and Forecasting

Introduction

Why monitor and forecast?

What should be monitored and forecast?

Where should monitoring and forecasting be carried out?

When should monitoring and forecasting be undertaken?

How can aphids be monitored and forecast?

Monitoring

Databases and data handling

Forecasting

Conclusions

Acknowledgements

References

20. Integrated Pest Management and Introduction to IPM Case Studies

Introduction

IPM as the use of multiple control measures

The golden rules of IPM

Interaction between chemical and biological control

Interaction between chemical control and host-plant resistance (HPR)

Interaction between biological control and host-plant resistance

Three-way interaction between chemical control, host-plant resistance and biological control

Interaction between cultural control and biological control

The IPM case studies

Conclusions

References

21. IPM Case Studies: Brassicas

Introduction

Biology of pest aphids in the UK

Integrated crop management

Chemical control

Monitoring and forecasting

Sampling and decision-making

Biological control

Host-plant resistance

Cultural control

Crop covers

Increasing crop diversity

Executive summary

References

22. IPM Case Studies: Berry Crops

Introduction

Aphid IPM in raspberry

Aphid IPM in blueberry

Aphid IPM in strawberry

Aphid IPM in grape

Acknowledgements

Executive summary

References

23. IPM Case Studies: Cotton

Introduction

Biological and ecological characteristics of Aphis gossypii

Infestation

Damage and its economic importance

Control and its evolution

The limits of chemical control of A. gossypii

Evolution towards integrated control

IPM of Aphis gossypii in the USA

IPM of Aphis gossypii in Brazil and elsewhere in South America

IPM of Aphis gossypii in South-east Asia and China

IPM of Aphis gossypii in Africa and Madagascar

Executive summary

References

24. IPM Case Studies: Leafy Salad Crops

Introduction

What are leafy salad crops?

The IPM challenge

The aphids

Components for aphid IPM

Chemicals and resistance to insecticides

Reducing insecticides

Biological control

Host-plant resistance

Modifying aphid behaviour

IPM in practice

Assurance and accreditation schemes

Practical control

Executive summary

References

25. IPM Case Studies: Grain

Introduction

Population dynamics

Damage

Direct damage

Indirect damage

Control possibilities

Chemical control

Forecasting systems

Monitoring and decision-making systems

Biological control

Host-plant resistance

Cultural control

Habitat management practices

Conclusions

Executive summary

References

26. IPM Case Studies: Seed Potato

Introduction

Certification

Vector species

Economic thresholds

Mathematical modelling

IPM tactics

Monitoring aphid flight

Chemical control

Biological control

Host-plant resistance

Cultural control

Executive summary

References

27. IPM Case Studies: Sorghum

Introduction

A short history of Schizaphis graminum on sorghum

Current greenbug management practices

Chemical control

Biological control

Host-plant resistance

Cultural control

Putting the pieces together

The 'current model' and the future

Conclusions

Executive summary

References

28. IPM Case Studies: Cucurbits

Introduction

Aphid-vectored viruses affecting cucurbits

Management options for aphids and aphid-vectored viruses in cucurbits

Chemical control

Biological control

Host-plant resistance

Cross-protection

Cultural control

IPM programmes for cucurbits that include aphid management

Executive summary

References

29. IPM Case Studies: Deciduous Fruit Trees

Introduction

Apple and pear aphids

Damage and virus transmission

Monitoring and economic thresholds

Chemical and supervised control

Biological control

Stone-fruit tree aphids

Damage and virus transmission

Monitoring and economic thresholds

Chemical and supervised control

Biological control

Acknowledgements

Executive summary

References

30. IPM Case Studies: Tropical and Subtropical Fruit Trees

Introduction

Citrus aphids

Damage and virus transmission

Monitoring and economic thresholds

Chemical and supervised control

Biological control

Tropical fruit tree aphids

Damage and virus transmission

Monitoring and economic thresholds

Supervised chemical control

Biological control

Acknowledgements

Executive summary

References

31. Decision Support Systems

Introduction

What is a Decision Support System?

Are aphids suitable subjects for the development of DSSs?

Examples of aphid and virus DSSs

Development and delivery of DSSs

Case studies

New Zealand Decision Support System

Western Australian Decision Support System

Conclusions

Acknowledgements

References

Taxonomic Glossary

APHIDS AND THEIR NATURAL ENEMIES

Aphidoidea

Natural enemies of aphids

OTHER INSECTS

Aleyrodoidea

Thysanoptera

Lepidoptera

Diptera

Coleoptera

Hymenoptera – Formicidae

Hymenoptera – Braconidae

ACARINA

NEMATODA

OTHER MICROORGANISMS

PLANTS

Index

A

B

C

D

E

F

G

H

I

J

K

L

M

N

O

P

R

S

T

U

V

W

X

Y

Z