NEMATOLOGY 100 MID-TERM EXAM -- 1
1/2 HOURS NOVEMBER 1, 1995
1. (25 points)
You are provided with a sample of nematodes that represent a
composite from several sources.
a. Place an adult female plant-parasitic nematode of any species on a
Kill the nematode with gentle heat or by placing in dilute formalin
soultion 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.
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 details of the method in describing a procedure appropriate
a) Radopholus similis from citrus roots. What stages would be
recovered by your method?
b) Longidorus africanus from soil. What stages would be recovered?
3. (10 points)
Describe the various excretory system of tylenchid nematodes. How
does it differ from that in the genus Trichodorus?
4. (15 points)
In the class so far you have studied and/or discussed at least four
genera of ectoparasitic nematodes that are classified in the same
superfamily and that have some similar morphological, anatomical, and,
maybe, feeding habit characteristics. Those genera are:
a) Paratylenchus, b) Criconemoides, c) Hemicriconemoides, and
Provide the following general and diagnostic characters of that these
nematodes have in common by circling the appropriate choice or filling
in the blank:
(i) Common Name: a)
(ii) Order: a) Tylenchida
(iii) Esophagus type : a) tylenchid - butting
b) tylenchid - overlapping,
(iv) Number of ovaries (female): a) one
c) more than two
(v) Known vector of a plant virus? a) no
(vi) Adult female feeding habit: a)
c) sedentary endoparasite
(vii) a) males common (probably reproducing sexually)
b) males uncommon (probably parthenogenic)
c) varies among the four genera but males usually have reduced
5. (10 points)
List 5 diagnostic characteristics of organisms in the Phylum Nematoda.
6. (10 points)
a) Describe the processes of acquisition, retention (retention sites,
mechanism and retention period), and transmission of plant viruses by
b) Which genera of nematodes transmit NEPO viruses?
What are the shapes and sizes of these virus particles?
7. (10 points)
Discuss the life history, feeding habits and mode of
parasitism and survival of the rice root nematode (Hirschmanniella oryzae).
8. (10 points)
What is the function of the following structures in nematodes?
c) Caudal alae
f) Postcorpus of the esophagus in Tylenchida
i) Metacorpus of the esophagus in Tylenchida
j) Post-uterine sac
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