EPWS 310  EXAM 3, Fall 2000

 

1. (12 pts) Briefly define the following terms:

 

autoecious

 

 

virion

 

 

rhizomorphs

 

 

anamorph

 

 

microcyclic

 

 

semipersistent

 

 

2. (8 pts) Give the genus of one fungus that causes leaf spots.  Describe how the pathogen overwinters, how it is disseminated and how it can be controlled.

 

 

 

 

 

 

 

 

 

3.  (8 pts) Outline the life cycle of corn smut.  Include how it overwinters, the two spore types, how it infects and how it causes disease.

 

 

 

 

 

 

 

 


4. (10 pts) Gray mold and white mold are devastating diseases.  What fungi causes these diseases, what types of diseases do they cause, how do they overseason, and what measures work to control them?

 

 

 

 

 

 

 

 

 

 

 

5.  (10 pts)  Answer the questions below about the disease cycle of ergot.  (For 5 points extra credit, answer the questions for brown rot of peaches.)

 

a) What is the survival structure?

 

 

b) What serves as primary inoculum

 

 

c) What serves as secondary inoculum?

 

 

d) What is the primary means of control?

 

 

e) What pathogen causes the disease?

 

 

 

6. (8 pts) Describe how a (-) ssRNA virus replicates in a cell

 

 

 

 

 

 

 

 


7.  (10 pts) Give an example of a fungal disease where fungicides will work well and one where it is of limited value and explain your answers.

 

 

 

 

 

 

 

 

 

8.  (10 pts)  For 2 viruses in different groups, discuss what types of symptoms they cause, what are the hosts, how they are transmitted (vector and persistence), and how they can be controlled.

 

 

 

 

 

 

 

 

 

 

9.  (14 pts)  Diagram the life cycle/disease cycle of cotton rust.  Show the nuclear state of all stages and which host it is on.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

10.  (10 pts) 7.  What type of situation (ie. crop, transmission characteristics, etc.) would you suggest using each of the following methods as a way to manage viral disease spread?

 

a.  insecticides

b.  host free period

c.  rogueing

d.  biological control of insect vector

e.  heat treatment of plant