Epidemic Development and the Measurement of Disease Levels and Crop Losses

  • G. R. Dixon


Epidemiology has been the subject of much recent experimentation and thought by pathologists. Basically, this is an attempt to quantify in scientific terms the reasons why epidemics develop in particular ways and to differentiate between different forms of epidemic. From this work has developed a set of equations describing disease incidence and relating this to the likely success of control techniques, especially the use of various forms of host resistance. The topic has evolved a mathematical basis, and hence prediction of epidemics has changed from an art to a science. In order to control plant pathogens by host resistance, by husbandry methods or by chemicals, it is essential to understand that host-parasite interactions differ in the manner of their development and their interrelation with the environmental conditions. Techniques of disease measurement and prediction need to become objective so that they may be applied on the widest possible basis. Hence disease assessment keys need to be internationally standardised, allowing uniform and unbiased evaluation of disease amount. Epidemiological studies now permit advance calculation of the likely life expectancy of novel forms of host resistance in relation to the capacity of the pathogen population to develop compatible virulences at high frequency levels. Such work is now becoming integrated with studies of population genetics of host and pathogen. Notice is also being taken of the need to quantify losses due to pathogens.


Powdery Mildew Downy Mildew Pathogen Population Disease Level Compound Interest 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Beaumont, A. and Staniland, L. N. (1933). A. Rep. Seale Hayne agric. College 1932Google Scholar
  2. Bourke, P. M. A. (1955). The Forecasting from Weather Data of Potato Blight and Other Plant Diseases and Pests, Technical Note No. 10. World Meteorological Organisation, 42, 3–48.Google Scholar
  3. Bourke, P. M. A. (1970). A. Rev. Phytopath. 8, 345–70.CrossRefGoogle Scholar
  4. Dixon, G. R. (1974a) Euphytica 23, 671–9.CrossRefGoogle Scholar
  5. Dixon, G. R. (1974b). PL Path. 25, 105–9.CrossRefGoogle Scholar
  6. Dixon, G. R., Tonkin, M. H. and Doodson, J. K. (1973). Ann. appl. Biol. 74, 307–13.CrossRefGoogle Scholar
  7. van Everdingen, E. (1926). Tijdschr. PlZiekt. 32, 129–39.Google Scholar
  8. Feekes, W. (1941). Vers XVII tech. Tarive Commissie, Groningen, 560–1.Google Scholar
  9. Grainger, J. (1969). The Reduction of Crop Disease Losses in West Scotland, Research Bulletin No. 43. West of Scotland Agricultural College, Ayr.Google Scholar
  10. Large, E. C. and Doling, D. A. (1962). Pl. Path. 11, 47–57.CrossRefGoogle Scholar
  11. Myers, A. and Watson, L. (1969). Nature, Lond. 223, 964–5.CrossRefGoogle Scholar
  12. van der Plank, J. E. (1963). Plant Diseases: Epidemics and Control. Academic Press, London.Google Scholar
  13. Priestley, R. H. (1978). Detection of increased virulence in populations of wheat yellow rust. In Plant Disease Epidemiology ( P. R. Scott and A. Bainbridge, eds). Blackwell Scientific Publications, Oxford.Google Scholar
  14. Selman, I. W. and Pegg, G. F. (1957). Ann. appl. Biot 45, 674–81.CrossRefGoogle Scholar

Further Reading

  1. Anon. (1971). Crop Loss Assessment Methods: Food and Agriculture Organisation Manual on the Evaluation and Prevention of Losses by Pests, Disease and Weeds (L. Chiarappa, ed.). Commonwealth Agricultural Bureau, Farnham Royal.Google Scholar
  2. Anon. (1976). Manual of Plant Growth Stages and Disease Assessment Keys. Ministry of Agriculture, Fisheries and Food, London.Google Scholar
  3. Kranz, J. (ed.) (1974). Epidemics of Plant Diseases: Mathematical Analysis and Modelling. Springer-Verlag, Berlin.Google Scholar
  4. Large, E. C. (1952). PL Path. 1, 109–17.CrossRefGoogle Scholar
  5. Large, E. C. (1955). Ann. appl. Biol., 42, 344–54.CrossRefGoogle Scholar
  6. van der Plank, J. E. (1968). Disease Resistance in Plants. Academic Press, London.Google Scholar
  7. van der Plank, J. E. (1975). Principles of Plant Infection. Academic Press, London.Google Scholar
  8. Scott, P. R. and Bainbridge, A. (1978). Plant Disease Epidemiology. Blackwell Scientific Publications, Oxford.Google Scholar

Copyright information

© G. R. Dixon 1981

Authors and Affiliations

  • G. R. Dixon
    • 1
  1. 1.Head of Horticulture DivisionSchool of AgricultureAberdeenUK

Personalised recommendations