1. (25 points) Note: read this question carefully, it is a little
different from previous years!
You are provided with a sample of nematodes that represent a
composite from several sources. The sources include a lawn, a grape
vineyard, and greenhouse pot cultures.
a. Place an adult female plant-parasitic nematode of any species on a
microscope slide.
Heat-kill the nematode with gentle heat before applying a coverslip.
Seal the edge of the coverslip with fingernail polish to prevent the
slide from drying out.
Place the slide on the compound microscope and adjust the microscope
to provide Köhler illumination.
b. Indicate on your exam sheet the Class and Order of your nematode.
c. Draw and label the component parts of the stylet and esophagus for
this type of nematode (either from your specimen, or from your
knowledge of anatomy and morphology, or both).
d. 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.
Grading:
adult female plant-parasite, good condition - 15 pts
non-parasite, good condition - 8 pts
correct designation of Class and Order - 2 pts
correct drawing and identification of stylet/esophagus - 8 pts
points off for damage, distortion, dry slides, etc.
2. (10 points) Provide a generalized drawing of the reproductive structures
of an adult male nematode in the Order Tylenchida. Label the parts.
3. (10 points) On the field trip you recovered the ring nematode from an
almond orchard. You also studied the nematode in the laboratory.
Provide the following general and diagnostic characters of this nematode
by circling the appropriate choice or filling in the blank:
(i) Genus:
(ii) Order: a) Tylenchida
b) Rhabditida
c) Diplogastrida
d)
Dorylaimida
(iii) Esophagus type : a) tylenchid - butting
b) tylenchid - overlapping,
c) dorylaimid
(iv) Number of ovaries (female): a) one
b) two
c) more than two
(v) Known vector of a plant virus? a) no
b) yes
(vi) Adult female feeding habit: a)
migratory ectoparasite, (vii) a) males common (probably reproducing sexually)
b) males uncommon (probably parthenogenic)
4. (10 points) List 5 diagnostic characteristics of organisms in the
Phylum Nematoda.
5. (15 points)
a) Describe the processes of acquisition, retention (retention sites,
mechanism and retention period), and transmission of plant viruses by
plant-parasitic nematodes.
b) Which genera of nematodes transmit TOBRA viruses?
What are the shapes and sizes of these virus particles?
6. (10 points) Briefly describe a method of separating nematodes from soil
that does not require the nematodes to be motile.
7. (15 points) Discuss the life history, feeding habits and mode of
parasitism and survival of the rice root nematode (Hirschmanniella oryzae).
8. (10 points) Describe the goegraphic location and soil conditions that
favor the sting nematode, Belonolaimus longicaudatus. What crops are
damaged?
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