Name   ______________________


            EPWS 310    EXAM 3    Fall 2004                     


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





nonpersistent stylet-borne


















(2 pts extra credit)  conk




2.    (8 pts) List the genus of an Basidiomycete fungus that causes root rot.  Describe how the pathogen overwinters, how it can be identified, how it is disseminated, and how the disease can be managed.











3.    (8 pts) List the genus of a fungus that causes vascular wilt, describe how the pathogen overwinters, how it is disseminated, how it causes disease, and how the disease can be managed.









4.    (6pts) Give an example of a fungal disease where plowing in the crop residue 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 loose smut of wheat caused by Ustilago nuda.  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.    (13 pts) In your job for Monsanto you are asked to develop a biocontrol agent (fungal or bacterial) to control wheat rust.  Explain which spore stage you will target and why.  Diagram the disease/life cycle of the rust, indicating which spore stages are found on which hosts. 















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


a) What is the survival structure?


b) What serves as secondary inoculum?


c) What are the primary means of control?


d) What pathogen causes the disease



10.  (12 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.  altering planting date

c.  sanitation of tools

d.  rogueing