NEMATOLOGY 100

Laboratory Exercise 11

Rev. 10/30/2008

Purpose:  Above-ground feeding nematodes:  morphology, anatomy, biology, feeding habits -- Ditylenchus and Anguina (Tylenchida, Tylenchina, Tylenchoidea, Anguinidae).

1.   Slide presentation of characteristics, including a review of Ditylenchus and Anguina.

2.   Tease apart galls on leaves of Wyethia mollis collected at at Donner Pass in summer 2000 and earlier.  Observe Anguina balsamophila in the coiled anhydrobiotic condition.  What stages are present in the galls? 

3.   Examine Anguina agrostis extracted from ryegrass seed after more than 25 years of storage.  What stages are present?

4.  Examine dried nematodes of Ditylenchus dipsaci and Anguina agrostis stored since 1964.  Are they still viable?

5.  Examine seed galls caused by Anguina tritici.

6.  If available, select green stem galls from Poa annua golf course turf.  Dissect the galls to release nematodes (Anguina pacificae).  What stages are present?  Is there evidence of bacteria in mature galls?

7.  Hand-pick live adults of Anguina balsamophila and Ditylenchus. dipsaci.  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.

8.   Note the taxonomic position of these nematodes in the order Tylenchida and suborder Tylenchina.

9.   Examine descriptive charts of these plant-parasitic nematodes in the Anguinidae.

10.   Videotapes:
          a)   The Burrowing Nematode
          b)   The Stem Nematode: a pest in agriculture.

11.  Anhydrobiosis Experiment:

        Pipette 0.5 ml of suspension of Aphelenchus avenae into a dry BPI watchglass and also into a BPI watchglass lined with water agar.  Or, place a piece of moist agar containing the nematodes in the BPI glass so that the drying occurs slowly.  The process of slow drying is critical to allow the nematodes to alter their physiology.

        Place the watchglasses in a covered petri dish and leave them to dry slowly on the lab bench.  

        At the next lab (or after they have dried) we will try to revive the nematodes.

12.  Study photographs of characteristics and damage by stem, bulb, bud and seedgall nematodes.

13.   Homework Assignment:

          NEMAPLEX Exercise
          Main Menu:
               Select...Biology and Taxonomy
                Select..Phylogenetic Classification
                 Select...Tylenchida
               Select...Anguinidae
                           Review Anguina, including A. tritici, A. agrostis and A. pacificae.
                           Review Ditylenchus, including D. angustus,   
                           D. destructor, D. dipsaci and D. myceliophagus.
                

14.   NEMABASE Exercise

Determine the host range for the genera Ditylenchus and Anguina.

In Nemabase select "All Plants" and "Genus" Ditylenchus, then  Anguina. 

Also examine the host range of individual species.
Set "Host" filter to Host.  Process.

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