NEMATOLOGY 100 MID-TERM EXAM -- 1 1/2 HOURS NOVEMBER 1, 1995

   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 or by placing in dilute formalin
           soultion before applying 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.

       Grading:
         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)
         Provide details of the method in describing a procedure appropriate
         for extracting:
      a)  Radopholus similis from citrus roots.  What stages would be
          recovered by your method?
      b)  Longidorus africanus from soil.  What stages would be recovered? 

   3.  (10 points)                                                      
         Describe the various excretory system of tylenchid nematodes.  How
         does it differ from that in the genus Trichodorus? 

   4.  (15 points)                                                            
        In the class so far you have studied and/or discussed at least four 
        genera of ectoparasitic nematodes that are classified in the same 
        superfamily and that have some similar morphological, anatomical, and,
        maybe, feeding habit characteristics.  Those genera are:   
        a) Paratylenchus, b) Criconemoides, c) Hemicriconemoides, and 
        d) Hemicycliophora.
        Provide the following general and diagnostic characters of that these
        nematodes have in common by circling the appropriate choice or filling 
        in the blank:

       (i) Common Name:  a)
                         b)
                         c)
                         d)

       (ii) Order: a) Tylenchida                                       
                   b) Rhabditida
                   c) Diplogastrida
                   d) Dorylaimida

      (iii) Esophagus type : a) tylenchid - butting
                             b) tylenchid - overlapping,
                             c) dorylaimid

      (iv) Number of ovaries (female): a) one
                                       b) two
                                       c) more than two

      (v) Known vector of a plant virus? a) no
                                         b) yes

      (vii) a) males common (probably reproducing sexually)
            b) males uncommon (probably parthenogenic)
            c) varies among the four genera but males usually have reduced
               feeding structures

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

   6.  (10 points)                                                             
       a)  Describe the processes of acquisition, retention (retention sites, 
           mechanism and retention period), and transmission of plant viruses by
           plant-parasitic nematodes.
       b)  Which genera of nematodes transmit NEPO viruses?  
           What are the shapes and sizes of these virus particles?

   7.  (10 points)
         Discuss the life history, feeding habits and mode of
         parasitism and survival of the rice root nematode (Hirschmanniella oryzae).
         

   8.  (10 points)
        What is the function of the following structures in nematodes?
        a)  Gubernaculum
        b)  Amphids
        c)  Caudal alae
        d)  Scutellum
        e)  Spermatheca
        f)  Postcorpus of the esophagus in Tylenchida
        g)  Stomatostyle
        h)  Cloaca
        i)  Metacorpus of the esophagus in Tylenchida
        j)  Post-uterine sac

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