EPWS 310 PLANT PATHOLOGY EXAM 2, Fall 2005
1. (2 pts each) Define the following:
2. a)(3 pts) What environmental conditions favor powdery mildews and why.
b) (2 pts) How can you microscopically differentiate among the genera of powdery mildew?
c) (3 pts) List two ways that powdery mildew overwinter.
d) (4 pts) What are two methods to control powdery mildew
e) ( 4 pts) What are two ways that you can determine if you a looking at a powdery mildew or a downy mildew?
f) (2 pts) How can you microscopically differentiate among the genera of downy mildew?
3. (4 pts) List 2 types of disease induced by Olpidium (Chytridiomycete) infection.
4. (4 pts) List 4 ways that Plasmodiophoromycetes differ from Ascomycetes.
5. (12 pts) Compare the disease, dissemination, primary inoculum, secondary cycles, overseasoning, and control for Phytophthora capsici infecting chile roots with grape disease caused by Plasmopora viticola.
6. (8 pts) What is the nuclear state of Oomycete and Ascomycete mycelia and when do plasmogamy, karyogamy, and meiosis occur?
7. (8 pts) A new local nursery calls you because their lettuce seedlings are dying before they can be sold. When you go to the store for the first time what will you look for in diagnosing the problem? What might you expect their disease problem to be? What pathogen(s) might you expect to isolate? What will you suggest to control or avoid the problem?
8. a)(4 pts) What environmental conditions favor peach leaf curly and why?
b)(4 pts) How does peach leaf curl differ from other pathogenic Ascomycetes?
9. (14 pts) Compare the disease, spore types, dissemination, asexual spore types, secondary cycles, survival, and control of Rhizopus infection of fruit with Pythium infection of carrot.
10. a)(2 pts) What conditions favor late blight of potato and why?
b) (6 pts) How does the pathogen overwinter, how is it disseminated, and how do these influence control?
(10 pts extra credit) Outline the disease cycle of club root of crucifers. What is thhe genus of the causal agent? How can the disease be controlled?