EPWS 310 EXAM 2, Fall 2014
1. (2 pts each) Define the following terms:
2. (9 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?
3. (4 pts) What are two types of diseases induced by Olpidium, a Chytridiomycete.
4. (12 pts) Compare the primary inoculum, dissemination mechanism, secondary inoculum, the fungal component that overseasons and the location that overseasoning occurs, and control of club root of crucifers and powdery mildew of roses.
5. (6 pts) List and explain 4 ways that Oomycetes differ from Glomeromycetes (Zygomycetes).
6. (6 pts) Both Rhizopus soft rot and damping off are problems primarily in man-made environments. What are the environmental conditions that promote each disease, what spore types are most responsible for spread, and how can each be controlled?
7. (12 pts) Compare the dissemination methods, primary inoculum, secondary inoculum, overseasoning methods and forms, and control of late blight of potato and downy mildew of grape. (Extra credit 2 pts each, give the genus of the causal agent).
8. ( 4 pts) Phytophthora ramorum, which causes sudden oak death, is of major concern in the US and Europe. Describe control of the disease in trees and shrubs in homeowner lawns and public parks.
9. You have been called to a local field to look at wilted dying chile plants. You suspect root rot.
a) (8 pts) How can you microscopically determine if you are looking at root rot caused by Phytophthora capsici or root rot caused by Pythium? Which fungal components would look similar and which would differ? Which of these two diseases would you more expect to find on young chile in April? On mature chile in August?
b) (18 pts) You decide that the wilt and root rot is caused by Phytophthora capsici. You need to explain the disease to the grower. Draw the disease cycle, 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.
c) (3 pts) The grower wants to know if changing their irrigation practices will help control the disease. Do you answer yes or no, and what control measures will you advise?
(8 pts extra credit) Outline the disease/life cycle of peach leaf curl. What is the causal agent (genus and species)? How can the disease be controlled?
(4 pts extra credit) On Monday, a woman from a local day care brought in a orange-colored growth from the bark chips on their playground. She wants to know if it will hurt the children, if she should be worried about it and how she can get rid of it. The bag is in the front of the room. Please come look at it when making your decision. What answers should I provide the woman when I email her?