NEMATOLOGY 100
Laboratory Exercise 5
Rev. 10/14/2008

Purpose:  Ectoparasitic nematodes:  morphology, anatomy, feeding habits -- Tylenchidae, Belonolaimidae, Dolichodoridae, Hoplolaimidae.

1.   Slide presentation of characteristics.

2.   Hand-pick live adult males and females of the true ectoparasites from samples provided.
a) Tylenchus spp. (small stomatostyle, butting esophagus, monovarial, pointed tail)
b) Tylenchorhynchus sp. - stunt nematode - (short stomatostyle, butting esophagus, diovarial, tapered to rounded tail)
 

Examine mounts of preserved specimens of

a) Dolichodorus heterocephalus - awl nematode - (rounded, offset lip region, long, slender stomatostyle, butting esophagus, diovarial, rounded tail)

b) Belonolaimus longicaudatus - sting nematode - long stomatostyle, overlapping esophagus, diovarial, pointed tail)

Also, hand-pick live adult males and females of the ectoparasite/migratory endoparasite Helicotylenchus sp.  (short stomatostyle, esophagus with a short ventral overlap, diovarial, rounded tail, spiral shape when relaxed).

Draw the nematodes observing the following characteristic features:

          a)   stylet length and morphology.
          b)   esophagus type and anatomy, nature of postcorpus interface with intestine.
          c)   male and female reproductive structures.
          d)   general shape when heat-relaxed.

     3.   Note the taxonomic position of these nematodes in the Tylenchoidea.

     4.   Examine charts of other plant-parasitic nematodes in these families.

     5.   Set up Baermann dishes to determine nematode survival after exposure to plant residues (lab #4).

     6.   Videotape:  Feeding of Trichodorus similis on roots of rape seedlings.

     7.   Videotape:  Nematode egg-laying and egg development (Pelodera sp.).
 
     8.   Observe nematodes extracted from student samples.

     9.   Study photographs of characteristics and damage by migratory ectoparasites: Tylenchorhynchus, Dolichodorus, Belonolaimus and family Tylenchidae.
 
    10.   Homework Assignment:
 
          NEMAPLEX exercise.
           Main Menu:
               Select...Biology and Taxonomy
                Select..Phylogenetic Classification
                 Select...Tylenchida
                  Select...Belonolaimidae
                              Dolichodoridae
                              Hoplolaimidae
                              ......Review information on genera and species discussed today:  
                                      Tylenchorhynchus
                                      Belonolaimus
                                     Dolichodorus
                                      Helicotylenchus
                                      Rotylenchus

     11.   Nemabase Exercise
 You can use Nemabase on Plant Pathology or Nematology computers.  You can also download and install it on your personal computer from:

http://ucipm.ucdavis.edu/NEMABASE/index.html

Review the host range of these nematodes.  What are the indicated non-hosts?
          In Nemabase select "All Plants" and "Genus" to the genus of interest.
          Set "Host" filter to Host.  Process.