EPWS 310 EXAM 2, Fall 2009
1. (2 pts each) Define the following terms:
2. A. (2 pts) How does peach leaf curl differ from other pathogenic Ascomycetes?
B. (2 pts) How does that influence the environmental conditions that favor the disease?
C. (2 pts) How can the disease be controlled?
(2 pts extra credit) List the genus and species of the fungus that causes peach leaf curl.
3. (16 pts) Compare the disease, primary inoculum types and locations, dissemination mechanisms, secondary inoculum types, overseasoning place and form, and control of Rhizopus on fruit and Phytophthora infestans on potato.
4. (10 pts) Make a flow chart or simple dichotomous key to differentiate the Ascomycetes, Oomycetes, Chytridiomycetes, Zygomycetes, and Plasmodiophoromycetes. Explain what characters differentiate the classes at each step of junction.
5. (12 pts) Compare the dissemination methods, primary inoculum, secondary inoculum, overseasoning methods and forms, and control of Sphaerotheca panosa, which causes powdery mildew on roses and Plasmopora viticola, which causes downy mildew on grape.
6. (18 pts) Draw the disease cycle of Phytophthora capsici, indicating what serves as primary inoculum, secondary inoculum, how it is disseminated, and how it overwinters. Include the sexual gametes and show where plasmogamy, karyogamy, and meiosis occur.
7. (10 pts) A local elementary school teacher calls with a problem. Her class project is to make a small vegetable garden plot outside their school. The kids plant the seed into pots and put them in the window of the classroom to grow large enough to transplant outside. The first round of plants worked great, but now, even though the plants are well-watered, many of the seedlings are dying. What will you look for when you visit the classroom? What do you expect the disease problem to be? What pathogens do you think that you might isolate from the plants? What will you suggest to the teacher to prevent the problem when they replant the pots again?
8. A. (2 pts) What conditions favor Phytophthora ramorum infection and why?
B. (4 pts) In what forms can the pathogen overwinter?
C. (4 pts) In what ways is the pathogen disseminated and how do these influence control?
(8 pts extra credit) Outline the disease/life cycle of club root of crucifer. What is the pathogen name (genus and species)? How can the disease be controlled?