NEMATOLOGY 100

Laboratory Exercise 15

Rev. 01/01/2020

Purpose:  Sedentary endoparasitic nematodes:  morphology, anatomy, biology, feeding habits -- Meloidogyne (Order Rhabditida, Suborder Tylenchina, Tylenchoidea, Heteroderidae).

1.   Powerpoint presentation and slides of characteristics.

2.   Inspect tomato roots infected with Meloidogyne incognita.  Note hyperplasia, galling.  Examine root surface for presence of egg masses. 

3.   Examine Meloidogyne incognita juveniles and males extracted from soil.  Examine stained roots for presence of other developmental stages.

4.   Dissect adult females from the tomato root system provided.  Place on a microscope slide in a small drop of lactic acid.  Carefully cut the perineal section from the posterior region of the female of each species and mount on a microscope slide for observation under the compound microscope.  Also try the "squash and roll" technique.

5.   Identify species of Meloidogyne from perineal patterns and protein patterns using the keys provided.

6.   Note the taxonomic position of the root-knot nematodes in the Order Rhabditida, Suborder Tylenchina.

7.   Anhydrobiosis Experiment (continued):

Objective:  To compare the survival of nematodes in soil allowed to dry for 5 and 12 days with that in soil kept moist. 

• Count the total number of nematodes in your 12-day drying samples from the Baermann funnels set up at the last lab (lab 14).  Centrifuge the sample, place on a slide, and determine the numbers of each type of nematode or functional guild (as in the Lab. Project analysis).  Each member of the group should do the identifications separately to normalize for differences of opinion on nematode identity!

Questions:

Are there differences in the survival rates of different nematode taxa or of nematodes with different feeding habits?

Other than differential survival in dry and moist soils, are there other explanations for differences among the samples?

Report findings to the class.

8.   Videotapes

•     Life Cycle of the Rootknot Nematode, Meloidogyne javanica.
•     Meloidogyne incognita infecting roots of Arabidopsis thaliana.

9.   Homework Assignment:

     a) Soil Suppressiveness experiment.

Push two microcosm cylinders into a soil of your choice and cap each end with a small petri dish to preserve an undisturbed core.  Label cylinders and bring to the next lab.

     b)  NEMAPLEX Exercise
          Main Menu:
               Select...Biology and Taxonomy
                Select..Phylogenetic Classification
                 Select...Order Rhabditida, Suborder Tylenchina
               Select...Heteroderidae
                Review Meloidogyne, including M. incognita, M. hapla, M. javanica, and M. arenaria.  
           Return to Main Menu
           

 10.   NEMABASE Exercise
       

         Review the host range of nematodes in the genera Meloidogyne.  What are the indicated non-hosts?  Are there resistant cultivars available?
          From the Nemaplex main Menu, select Management and Decision Support, then Nemabase 2012.

         Alternatively, you can access the data from the descriptive page for each nematode. 

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