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:
(ii) Order: a) Tylenchida
(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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