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





horizontal resistance



ring spot



incompatible interaction






disease incidence



loose smut



dwarf mistletoe



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








3.     (6 pts) Altering cropping density 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) dodder

















9.     (5 pts)  Migratory endoparastic nematodes can cause severe problems on hosts such as peanut.  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 boxwood shrubs at a local nursery.  The manager tells you that they recently got a large shipment of boxwoods in with chlorotic and necrotic lesions on the leaves.  Some of the plants are somewhat defoliated.  The roots appeared to be ok and the plants were well watered. 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?





















11.  (5 pts)  White pine blister rust causes severe problems to the forest trees in New Mexico.  White pines are completely susceptible and you donŐt want to pour herbicides over the mountains to kill all the Ribes (alternate host).  You have decided to write a grant to develop resistance (transgenic or conventional) in pine to the disease.  What pathway, growth factor, or plant part will you try to improve?  What types of genes will you modify or add to the plant?