EPWS 310 EXAM 2, Fall 2003
1. (2 pts each) Define the following terms:
2. (4 pts) Contrast the control of damping off with control of Rhizopus soft rot.
3. (3 pts) List two ways that downy mildew fungi overwinter?
4. (4pts) List 2 types of diseases induced by Olpidium (Chytridiomycete) infection?
5. (6 pts) List 4 ways that Oomycetes differ from Ascomycetes.
6. (3 pts) Compare control of slime mold on turf with sooty mold on beans.
7. (6 pts) Contrast the control of Rhizopus soft rot with that of damping off.
8. (8 pts) Which classes of fungi that we discussed in class produce zoospores? What environmental conditions favor diseases caused by these fungi? What methods can be used to control all these fungi?
9. (12 pts) Compare the dissemination, primary inoculum, secondary cycles, and overseasoning of the disease cycles of late blight of potato and Phytophthora crown and root rot.
10. You have been called to the field to look at mildew on grapes.
a) (4 pts) What are two ways that you can determine if you are looking at powdery mildew or downy mildew?.
b) (3 pts) You decide that it is powdery mildew. How can you microscopically differentiate among the genera of powdery mildew to determine which one is present?
c) (20 pts) You need to explain the disease to the grower. Draw the disease cycle of powdery mildew, indicating what serves as primary inoculum, secondary inoculum, how it is disseminated, and how it overwinters. Also show where in the cycle that meiosis, plasmogamy, and karyogamy occur.
d) (6 pts) The grower wants to know if changing their water management will help control the disease. Do you answer yes or no, and if no, what control measures will you advise?
11. ( 5 pts) List 2 ways that the peach leaf curl fungus differs from the rest of the Ascomycete plant pathogens and explain how this influences fungicide control.
(8 pts extra credit) Outline the disease/life cycle of club root of crucifers caused by Plasmodiophora brassicae. How can the disease be controlled?