Microbial Plant Pathogens: Detection and Management in Seeds and Propagules

Healthy seeds and propagules are the basic requirement for producing good grains, fruits and vegetables needed for human survival and perpetuation. Dispersal of microbial plant pathogens via seeds and propagules has assumed more importance than other modes of dispersal, as infected seeds and propagules have the potential to become the primary sources of carrying pathogen inoculum for subsequent crops. Several diseases transmitted through seeds and propagules have been shown to have the potential to damage economies as a result of huge quantitative and qualitative losses in numerous crops. Hence, it is essential to rapidly detect, identify and differentiate the microbial plant pathogens present in seeds and propagules precisely and reliably, using sensitive techniques.

Microbial Plant Pathogens: Detection and Management in Seeds and Propagules provides a comprehensive resource on seed–borne and propagule–borne pathogens. Information on the biology of microbial pathogens, including genetic diversity, infection process and survival mechanisms of pathogens and epidemiology of diseases caused by them, are discussed critically and in detail to highlight weak links in the life cycles of the pathogens.
Development of effective disease management systems, based on the principles of exclusion and eradication of pathogens and immunization of crop plants to enhance the levels of resistance of cultivars to diseases, has been effective to keep the pathogens at bay. The need for production of disease–free seeds/propagules has been emphasized to prevent the carryover of the inoculum to the next crop or introduction of the pathogens to other locations. Effectiveness of adopting simple cultural practices and development of cultivars resistant to diseases through traditional breeding methods or biotechnological approach have resulted in reducing the pathogen inoculum and disease incidence. Although application of different chemicals may reduce the disease incidence effectively, biological management of crop diseases, employing potential biological control agents have to be preferred to preserve the agroecosystems. Greater efforts have to be made to integrate compatible strategies to enhance the effectiveness of diseases management systems.
Protocols appended at the end of relevant chapters form a unique feature of this book to enable the researchers to fine–tune their projects.

This 2 volume set provides comprehensive and updated information about the economically–important groups of microbial plant pathogens carried by seed and propagules. Graduate students, researchers and teachers of plant pathology, plant protection, microbiology, plant breeding and genetics, agriculture and horticulture, as well as certification and quarantine personnel will find the information presented in this book useful.

 

Preface

Acknowledgement

1. Introduction

1.1 Concepts and implications of pathogen infection of seeds and propagules

1.2 Economic importance of seed– and propagule–borne microbial pathogens

1.3 Nature of seed– and propagule–borne microbial pathogens

1.4 Development of crop disease management systems

References

2. Detection and identification of fungal pathogens

2.1 Detection and differentiation of fungal pathogens in seeds

2.2 Detection and differentiation of fungal pathogens in propagules

Appendix

References

3. Biology of fungal pathogens

3.1 Biological characteristics

3.2 Physiological characteristics of fungal pathogens

3.3 Genotypic characteristics of fungal pathogens

3.4 Influence of storage conditions

Appendix

References

4. Process of infection by fungal pathogens

4.1 Invasion paths of seedborne fungal pathogens

4.2 Invasion paths of propagule–borne fungal pathogens

References

5. Detection and identification of bacterial and phytoplasmal pathogens

5.1 Detection and identification of bacterial pathogens

5.2 Detection of bacterial pathogens in propagules

5.3 Detection of phytoplasmal pathogens

Appendix

References

6. Biology and infection process of bacterial and phytoplasmal pathogens

6.1 Biology of bacterial pathogens

6.2 Disease cycles of seedborne bacterial pathogens

6.3 Disease cycles of propagule–borne bacterial pathogens

6.4 Biology of phytoplasmal pathogens

6.5 Disease cycles of phytoplasmal pathogens

Appendix

References

7. Detection and identification of viruses and viroids

7.1 Detection of viruses in seeds

7.2 Detection of viruses in propagules

7.3 Detection of viroids in seeds

7.4 Detection of viroids in propagules

Appendix

References

8. Biology and infection process of viruses and viroids

8.1 Characteristics of plant viruses

8.2 Biological properties of viruses

8.3 Infection process of plant viruses

8.4 Characteristics of viroids

8.5 Infection process of viroids

References

9. Epidemiology of seed– and propagule–borne diseases

9.1 Epidemiology of fungal diseases

9.2 Epidemiology of bacterial diseases

9.3 Epidemiology of virus diseases

References

10. Crop disease management: Exclusion of pathogens

10.1 Health status of seeds and propagules

10.2 Plant quarantines for preventing entry of microbial pathogens

10.3 Production of disease–free seeds and propagules

Appendix

References

11. Crop disease management: Reduction of pathogen inoculum

11.1 Reduction of pathogen inoculum by cultural practices

11.2 Reduction of pathogen inoculum by physical techniques

11.3 Reduction of pathogen inoculum by chemical techniques

References

12. Crop disease management: Enhancement of genetic resistance of crop plants

12.1 Kinds of disease resistance

12.2 Identification of sources of resistance to crop diseases

12.3 Improvement of disease resistance through biotechnological approaches

References

13. Crop disease management: Biological management stratetgies

13.1 Evaluation of biotic agents for biological control potential

13.2 Evaluation of abiotic agents for biological control potential

13.3 Methods of application of formulated products of biological control agents

13.4 Integration of biological control with other management practices

References

14. Crop disease management: Chemical application

14.1 Application of chemicals

References

15. Crop disease management: Integration of strategies

15.1 Development of integrated disease management systems

15.2 Management of fungal diseases

15.3 Management of bacterial diseases

15.4 Management of virus diseases

References

Index

About the Author
P. Narayanasamy, served in various capacities as Postdoctoral Research Fellow, International Rice Research Institute, Philippines, as Virus Pathologist at the Indian Agricultural Research Institute, New Delhi and as Professor and Head, at the Tamil Nadu Agricultural University, India.