NEMATOLOGY 100 MID-TERM EXAM -- 1 1/2 HOURS NOVEMBER 3, 1993

   1.  (20 points) You are provided with a mixture of nematodes extracted from 
       several soil samples.
       Place an adult female plant-parasitic nematode that is either a "spiral
       nematode" (genus Helicotylenchus) or a "lesion nematode" (genus 
       Pratylenchus) on a microscope slide.
       Heat-kill the nematode with gentle heat before applying a coverslip.
       Place the slide on the compound microscope.                          
       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.  You should not have to leave your bench position.
       Grading:
         adult female spiral or lesion nematode, good condition     20 pts
         plant-parasite not spiral or lesion nematode               14 pts
         non-parasite, good condition -                              8 pts
         points off for damage, distortion, dry slides, etc.
   2.  (15 points)  What is the function of the following structures in 
       nematodes?

      a)  Gubernaculum
      b)  Phasmids
      c)  Odontophore
      d)  Scutellum
      e)  Spermatheca
      f)  Postcorpus of the
esophagus in Tylenchida
      g)  Labial papillae
      h) 
Cloaca
         

   3.  (10 points)  Under the dissecting microscope it is possible to see 
       several configurations of the interface of esophagus and intestine.  
       Briefly describe those configurations.  How do they appear to relate to 
       parasitic feeding habits?
   4.  (15 points) Provide a generalized drawing of an adult male nematode 
       with a tylenchid esophagus.
       Label the features of the reproductive and digestive tracts.
   5.  (10 points)  Briefly describe the technique that you would use to detect
       the following nematodes:
     a)  the sting nematode from soil and root samples from a golf course.
     b)  Paratrichodorus minor causing damage in onions.
     c)  Pratylenchus vulnus on bare root walnut nursery stock
     d)  Xiphinema americanum in an apple orchard
     e)  Mesocriconema xenoplax in a peach orchard
   6.  (10 points) How does the rice root nematode (Hirschmanniella oryzae) 
       reduce yield of rice.  What factors affect its survival between crops?
       What is its mode of parasitism?
   7.  (10 points) Describe the geographic location and soil conditions that 
       favor the awl nematode, Dolichodorus heterocephalus.  What crops are 
       damaged?
   8.  (10 points)  What are the characteristics of virus particles vectored
       by nematodes in the genus Xiphinema?  Indicate two virus diseases, the 
       crops affected and the species of Xiphinema that vector each virus.
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