CROP PESTS (ACE1022)
Self-Test Questions

General plant pathology

  1. What kinds of organisms can cause plant diseases?
  2. What are the three key criteria of successful disease control?
  3. What is the difference between 'symptoms' and 'signs'?
  4. Define 'biotrophic' and 'necrotrophic'.
  5. What is the structure by which many biotrophic pathogens obtain their nutrients from plant cells?
  6. How do necrotrophic pathogens damage plants?
  7. Why does host uniformity increase the danger of disease epidemics?
  8. What are the four stages of the typical infection cycle?
  9. What is the significance of whether one or many cycles of a disease occur in a growing season?
  10. What are three mechanisms by which fungal pathogens are dispersed?
  11. What is the major mechanism by which viral pathogens are dispersed?
  12. What are the key environmental factors that influence the development of plant diseases?
  13. What is the use of trying to predict disease severity?
  14. How can pathogens be excluded?
  15. Why is it sometimes useful to grow plants where a pathogen is absent?
  16. List three cultural practices for minimising initial inoculum.
  17. What was the first successful chemical for plant disease control?
  18. Why are systemic fungicides in general preferable to protectant fungicides?
  19. But what is the major problem with systemic fungicides?
  20. And are there any ways to reduce this problem?
  21. What are the principal mechanisms by which plants resist diseases?
  22. What are 'major-gene' and 'polygenic' resistance, and what are their respective advantages and disadvantages?
  23. Why is biological control not more widely used?
  24. How can genetic engineering be used to control plant viruses?
  25. In what ways do oomycetes differ from 'true' fungi?
  26. In what ways do basidiomycetes differ from ascomycetes?

Specific diseases

  1. Powdery mildew of cereals
  2. Septoria blotch of wheat
  3. Scald of barley
  4. Take-all of wheat
  5. Rusts of cereals
  6. Potato late blight