MIDTRM96.HLP                                             Rev 10/96

   Nematology 100        MID-TERM EXAM     10/30/1996     90 minutes

   1.  (25 points) 
       You are provided with a sample of nematodes that represent a
       composite from several sources.
       a.  Place an adult female plant-parasitic nematode of any species on a 
           microscope slide.
           Kill the nematode with gentle heat.
           Apply a coverslip.
           Seal the edge of the coverslip with fingernail polish to prevent the
           slide from drying out.
           Place the slide on the compound microscope and adjust the microscope
           to provide Köhler illumination.
       b.  Indicate on your exam sheet the Class and Order of your nematode.
       c.  Draw and label the component parts of the stylet and esophagus for 
           this type of nematode (either from your specimen, or from your 
           knowledge of anatomy and morphology, or both).
       d.  Call the instructor for examination of your nematode.  If there is 
           more than one nematode present in the microscope field, indicate the 
           specimen you wish to have examined.  Do not ask or expect the 
           instructor to make the selection.
           Only the nematode that you indicate initially will be considered.

         adult female plant-parasite, good condition -              15 pts
         non-parasite, good condition -                              8 pts
         correct designation of Class and Order -                    2 pts
         correct drawing and identification of stylet/esophagus -    8 pts
         points off for damage, distortion, dry slides, etc.

  2.   (10 points)
       Describe the chemo- and tactile-sensory structures of Tylenchid
       nematodes and discuss their apparent function.

  3.   (15 points)
       Provide a generalized drawing of an adult male nematode of the Order
       Tylechida, with the esophageal glands of about equal size and bounded
       by a membrane.                            
       Label the features of the esophageal and stoma regions and of the 
       reproductive and digestive tracts.
       Provide an example of a nematode genus with the characteristics you
       have drawn.  
       Indicate whether you expect this nematode to feed as an ectoparasite
       or an endoparasite, and why.

   4.  (15 points)                                                              
       Briefly describe the technique that you would use to detect the presence
       of the following nematodes in a sample:
   a. Pratylenchus vulnus in bare-root grapevine nursery stock.
   b. Pin nematode in fallow soil in which onions will be planted.
   c. Radopholus similis in a sample from a banana plantation.
   d. Xiphinema americanum in an apple orchard.
   e. Mesocriconema xenoplax in a peach orchard.

   5.  (15 points)                    
       Radopholus similis is an important parasite of bananas in the Ivory 
         Coast of West Africa.
         Describe the damage that this nematode causes to the plant root system.
         Describe how this damage translates into crop loss.
         What methods are used to eliminate the nematode from planting stock?
         What methods are used to minimize the nematode damage in established 

   6.  (10 points)                                                             
       Which genera of nematodes transmit NEPO viruses?  Give an example of a
       NEPO virus, the plant host, and the nematode vector.

   7.  (10 points)
       List 5 diagnostic characteristics of organisms in the Phylum Nemata.