EPWS 310 FINAL EXAM,  FALL 2005

 

 

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

 

pathogen

 

 

vertical resistance

 

 

mosaic

 

 

incompatible interaction

 

 

oospore

 

 

disease severity

 

 

loose smut

 

 

phytoplasma

 

 

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

 

 

 

 

 

 

3.     (6 pts)  Crop rotation is often used to manage plant diseases of annual crops.  Give a disease example when crop rotation 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 (crown gall and angular leaf spot of cotton) 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 powdery mildew on chile or Verticillium wilt of cotton, explain which factors you would chose in designing a predictive model of disease for New Mexico and why.  For 3 pts extra credit answer for both diseases.

 

 

 

 

 

 

 

7.      (12 pts)  Using the disease pyramid, discuss the epidemiology 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) downy mildew fungus such as Plasmopora which infects grape, (2) a vascular wilt fungus such as Verticillium or Fusarium, (3) fire blight bacteria, (4) root knot nematode, (5) beet curly top virus, and (6) dodder.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9.  (5 pts)  a) 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 the cause?

 

 

 

 

 

 

 

 

 

10  (10 pts)  Due to your experience in this class you have been called to look at a grape vineyard in Deming.  The leaves on the plants are yellow or necrotic at the margins of the leaves. The 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 the next yearŐs crop?

 

 

 

 

 

 

 

 

 

 

 

 

 

11. (5 pts)  What is a transgenic plant?  Give an advantage and a disadvantage of using transgenic plants to control plant diseases.