Lab. Exercise 18

NEMATOLOGY 100

Laboratory Exercise 18

Rev. 01/01/2020

Purpose: Economics of the nematode management decision process.

Note: Please bring laptop computers for Laboratory 19 on 12/5/12.

1. Powerpoint presentation and slides: Physical and cultural management of plant-parasitic nematodes.

2. Analyze soil suppressiveness experiment set up in Lab 17:

Determine the suppressiveness of each soil by the relative number of Heterodera bacteriophora recovered from the faunated and defaunated treatments. Are there differences between the soils and the organism-free sand?

Report to the class on soil suppressiveness.

3. Nematodes of grapevines: PowerPoint presentation as an example for management of a nematode community.

The Soil Food Web: Powerpoint presentation on food web structure, function and management.

4. Discussion of management decisions and information delivery.
Components of a simple expert system for nematode management decisions.

            a. Nematode/plant compatibility chart - consider need for a database, e.g. Nemabase.
            b. Relationship between numbers and plant growth - key pest.
            c. Relative value of other nematodes in terms of key pest - pathogenic equivalents - how to estimate.
            d. Environmental suitability parameters:

soil texture
geographic region
crop season

e. Seasonal multiplication rates - literature and experimentation, extrapolate.

f. Decline rates - winter and non-host - literature and experiments.

g. Annual multiplication rates.

h. Control costs:

nematicides
crop rotation, alternate crops - what is predominant species (key pest)?
resistant varieties - what is the predominant species (key pest)?

            i. Steady-state population convergence.
            j. Initial population assessment - reliability, variability, alternatives.
            k. Economic analysis:

consider production costs
potential crop value
grower perception and management objective
steady-state population.

l. Development of user-friendly software

expert systems protocols.
- Economic Threshold Model
- Cropping Sequence Optimizer
  - Determine the effects of changes in management costs, crop values and nematode virulence.
  - Determine the impact of crop values and nematode survival rate under nonhost conditions.
  - Report to class.

5. PowerPoint presentations:

Nematode damage thresholds.

6. Videotapes:

The proper handling and application of Telone soil fumigants.
Soil Sampling for Soybean Cyst Nematode

7. Homework Assignments:

Review Laboratory 19 assignment and start planning your strategy.

          NEMAPLEX Exercise
          Main Menu:
            Select...Management and Decision Support
               Select...Nematode Management
                  Review: Principles of Nematode Management.
                           Tactics: (Various tactics listed)
                           Emerging Research Developments: (Various topics)
           Return to Main Menu
            Select...Literature
                     Review current research on Nematode Management.

8. Use Nemabase2010 to review susceptibility and/or resistance of plants to different nematode species.

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