Nematology 100 MID-TERM EXAM 10/29/97 90 minutes 1. (25 points) You are provided with nematodes that represent a composite of samples from bulb fields and walnut orchards recently submitted to the Nematology Extension Laboratory. a. Place an adult female plant-parasitic nematode of any species on a microscope slide. Kill the nematode with gentle heat. Apply 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) Describe the various sensory structures of Tylenchid nematodes and indicate their position on a sketch of a nematode. Briefly discuss the apparent function of each structure. 3. (10 points) Provide a generalized, labelled drawing of the reproductive system of an adult female nematode that is diovarial, amphidelphic and sexually reproducing. 4. (15 points) Briefly describe the technique that you would use to detect the following nematodes: a. Paratylenchus hamatus (a pin nematode) from soil around walnut roots b. Pratylenchus vulnus (a lesion nematode) in bare-root nursery stock c. Belonolaimus longicaudatus (sting nematode) in fallow soil 5. (15 points) Helicotylenchus multicinctus (a spiral nematode) and Radopholus similis (a burrowing nematode) are important parasites of bananas on the Ivory Coast of West Africa. a. What types of damage do they cause to the plant tissues? b. What is the economic effect on crop yield and value? c. What are the approaches used for reducing the damage? 6. (10 points) Which genera of nematodes transmit NEPO viruses? Give two examples of NEPO virus diseases and indicate the crop affected. 7. (15 points) Describe the life cycle, feeding habits, damage symptoms and unique anatomical features of the stubby root nematode Paratrichodorus minor.