EPWS 310  EXAM 2, Fall 2002

 

1.  (2 pts each) Define the following terms:

 

haustorium

 

 

conidiophore

 

 

cleistothecium

 

 

antheridium

 

 

rhizoids

 

 

chlamydospore

 

 

aseptate

 

 

meiosis

 

 

2.  a)  (4 pts)  What environmental conditions favor downy mildews and why?

 

 

 

      b)  (2 pts)  How can you microscopically differentiate the genera of downy mildews?

 

 

 

3.   a)  (4 pts)  What environmental conditions favor peach leaf curl and why ?

 

 

 

      b)  (2 pts)  How can peach leaf curl be controlled?

 

 

 


4.   a) (4 pts)  What environmental conditions favor damping off and why?

 

 

 

      b)  (2 pts)  How can damping off be controlled?

 

 

 

5.  (12 pts) make a simple dichotomous key (or flow chart) to differentiate the Plasmodiophoromycetes, Chytridiomycetes, Oomycetes, Zygomycetes, and Ascomycetes.  Explain what characters differentiate the classes at each step or junction..

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


6.  (18 pts)  Compare and contrast Rhizopus rots of vegetables with powdery mildew of rose, including colonization, disease, overseasoning structures, asexual spore formation, environmental effects, and control.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7.  (12 pts) What is the nuclear state of Oomycete and Zygomycete mycelia and when does plasmogamy, karyogamy, and meiosis occur?

 

 

 

 

 

 

 

 

 

 

 

 

 


8. (20 pts)  Compare and contrast the life/disease cycle of Phytophthora capsici causing chile root rot with that of downy mildew of grapes caused by Plasmopora viticola.  Make sure to include both reproductive phases as well as dissemination and overseasoning, primary inoculum, secondary cycles, and control.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9.  (4 pts)  How do endomycorrhizae help their plant hosts?

 

 

 

 

 

 

 

(10 pts extra credit)  Outline the disease/life cycle of club root of crucifers.  What is the genus/species of the causal agent?  How can be the disease be controlled?