EPWS 310 FINAL EXAM, FALL 2008

 

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

 

parasite

 

 

vertical resistance

 

 

mosaic

 

 

incompatible interaction

 

 

plasmodium

 

 

disease incidence

 

 

loose smut

 

 

phytoplasma

 

 

2.     (6 pts)  Give specific examples of how plant nutrition influence biotic and abiotic diseases.

 

 

 

 

 

 

 

3.     (6 pts) Altering planting date can be used to manage plant diseases of annual crops.  Give a disease example of when this will work well, and an example when it will not help control a disease of an annual crop.

 

 

 

 

 

 

4.     (12 pts)  Chose one of the following bacterial diseases (ring rot of potato or crown gall) and answer the questions below about its disease cycle.  For 6 extra credit points, answer both questions.

 

a)    What are the symptoms of the disease?

 

 

b)   How does the pathogen enter the plant?

 

 

c)    How is the pathogen disseminated?

 

 

d)   Where does the pathogen overwinter?

 

 

e)    How can the pathogen be controlled?

 

 

f)     What is the genus of the pathogen?

 

 

5.     (10 pts)  Draw and label disease progress curves for polycyclic and monocyclic diseases.  Name a disease that would show each type of curve.

 

 

 

 

 

 

 

 

 

 

6.     (6 pts)  Choosing either Alternaria leaf spot of tomato or Fusarium wilt of tomato, explain which factors you would select in designing a predictive model of disease for northern New Mexico and why.  For 3 pts extra credit answer for both diseases.

 

 

 

 

 

 

 

 

 

7.     (12 pts)  Using the disease pyramid, discuss the epidemiology (and each component) of a specific (1) fungal disease, (2) bacterial disease, (3) viral disease, and (4) nematode disease.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8.     (12 pts)  Compare the dissemination and overwintering survival of (1) a downy mildew fungus, (2) Rhizopus soft rotter(3) fire blight bacteria, (4)  root knot nematode (5) alfalfa mosaic virus, and (6) true leafy mistletoe

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9.     (5 pts)  Migratory ectoparasitic nematodes can cause severe problems on a wide range of hosts such as corn and turf.  How do they interact with the plant?  What sorts of symptoms do they cause?

 

 

 

 

 

 

 

10.  (10 pts)  Due to your experience in this class, you have been called to look at an onion field in the north western part of the state.  The grower tells you that the leaves and seed stalks have large diamond-shaped yellow or necrotic spots.  Describe the steps you will take to diagnose the problem.  What type of pathogen would most likely cause the disease?  What control measures would you suggest for next yearŐs crop to decrease the problem?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11.  (5 pts)  Soybean rust is one of the most important disease problems currently in plant pathology.  You are writing a grant for funds to develop transgenic resistance to the disease in soybean.  Which component or pathway will you try to improve?  What type of genes will you modify or add to the plant?