Name   ______________________

 

            EPWS 310    EXAM 3    Fall 2014            

 

1.    (2 pts each) Briefly define the following terms:

 

virion

 

 

persistently propagative

 

 

microcyclic rust

 

 

perithecium

 

 

heterokaryon

 

 

pycnidia

 

 

rhizomorph

 

 

mosaic

 

 

 

2.    (8 pts) For a Basidiomycete fungus that that causes heart rot of trees, describe how the pathogen overwinters, how it is disseminated, and how the disease can be managed on fruit trees and on forest trees. 

 

 

 

 

 

 

 

3.    (8 pts) List the genus of an Ascomycete fungus that causes root rot.  Describe how the pathogen overwinters, how it is disseminated, and how the disease can be managed.

 

 

 

 

4.    (5pts) Give an example of a fungal disease where crop rotation works well to limit disease and another example where it does not work well and explain your answers.

 

 

 

 

 

 

 

5.    (8 pts) List the steps for a (-) ssRNA plant virus to replicate beginning with entry into a cell and concluding with exit from a cell.  What steps differ if the virus is (+) ssRNA?

 

 

 

 

 

 

 

 

 

 

 

 

6.    (8 pts) Explain the life cycle of covered smut (bunt) of wheat caused by Tiletia.  Include how it overwinters, the spore type(s) it produces, how it infects, and how it causes disease.

 

 

 

 

 

 

 

7.    (15 pts) For 3 viruses in different groups, explain what types of symptoms they cause, what hosts they typically infect, how they are transmitted (vector and persistence), and how they can be controlled.

 

 

 

 

 

 

 

 

 

 

 

 

8.    (9 pts)  Diagram the disease/life cycle of wheat rust, indicating which spore stages are found on which hosts.  (For 7 extra credit points give the nuclear state (ploidy) of all stages.)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9.    (8 pts) Answer the questions below about the disease cycle of apple scab.  (For 4 extra credit points, answer the questions for brown rot of peaches.)

 

a) What is the survival structure?

 

 

b) What serves as secondary inoculum?

 

 

c) What are the primary means of control?

 

 

d) What pathogen (genus, species) causes the disease

 

 

 

10.  (15 pts)  For each of the following methods explain the type of situation (transmission characteristics, vectors, crops etc) in which it would work (+) and not work (-) as an effective way to manage viral disease spread

 

a.  systemic insecticide

b.  removing weed hosts

c.  sanitation of tools

d.  altering planting date

e.  crop free period