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











compatible interaction






disease severity






dwarf mistletoe



2.     (5 pts)  Give specific examples of how plant nutrition can influence biotic and abiotic disease.







3.     (6 pts)  Sanitation steps suchas remvoing crop residue and cleaning tools can be used to manage plant diseases.  Give a disease example when sanitation will limit disease and an example when it will not decrease disease.





4.     (12 pts)  Chose one of the following bacterial diseases (crown gall or bacterial cancer of stone fruit) 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 disease 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 Fusarium bulb rot of onion or Stemphilium leaf spot of alfalfa, explain which factors you would chose in designing a predictive model of disease for northern New Mexico and why.  For 3 pts extra credit answer for both diseases. (Hint:  Stemphilium is closely related to Alternaria)







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) Pythium, (2) a fungus causing leaf spots such as Septoria, (3) an Erwinia causing soft rot, (4) root knot nematode, (5) zucchini yellow mosaic potyvirus, and (6) dodder.













9.  (5 pts) Migratory endoparasitic nematodes can cause severe problems on a hosts such as peanut.  How do they interact with the plant? What sorts of symptoms do they cause?









10  (10 pts)  During your vacation to Italy (gift for graduation) you hear about a possible disease of olives that is causing panic among growers.  You read online that although the officials are not certain of the cause, they are chain sawing and burning the trees to control possible spread into the top olive growing regions.  The death of these 500 to 1,00 year old trees is causing protests and clashes with police, because many growers believe it is all a plot to run them out of business.  The newspaper describes symptoms as leaf scorch, drying of leaves, followed by rapid death of the trees. There is likely a spittlebug associated with the disease in some way.  To impress your friends and maybe preserve some awesome trees, you decide to viisit the groves. 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. (6 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?