1. (20 points) You are provided with a mixture of nematodes extracted from several soil samples. Place an adult female plant-parasitic nematode that is either a "spiral nematode" (genus Helicotylenchus) or a "lesion nematode" (genus Pratylenchus) on a microscope slide. Heat-kill the nematode with gentle heat before applying a coverslip. Place the slide on the compound microscope. 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. You should not have to leave your bench position.
Grading: adult female spiral or lesion nematode, good condition 20 pts plant-parasite not spiral or lesion nematode 14 pts non-parasite, good condition - 8 pts points off for damage, distortion, dry slides, etc.
2. (15 points) What is the function of the following structures in nematodes?
f) Postcorpus of the esophagus in Tylenchida
g) Labial papillae
3. (10 points) Under the dissecting microscope it is possible to see several configurations of the interface of esophagus and intestine. Briefly describe those configurations. How do they appear to relate to parasitic feeding habits?
4. (15 points) Provide a generalized drawing of an adult male nematode with a tylenchid esophagus. Label the features of the reproductive and digestive tracts.
5. (10 points) Briefly describe the technique that you would use to detect the following nematodes: a) the sting nematode from soil and root samples from a golf course. b) Paratrichodorus minor causing damage in onions. c) Pratylenchus vulnus on bare root walnut nursery stock d) Xiphinema americanum in an apple orchard e) Mesocriconema xenoplax in a peach orchard
6. (10 points) How does the rice root nematode (Hirschmanniella oryzae) reduce yield of rice. What factors affect its survival between crops? What is its mode of parasitism?
7. (10 points) Describe the geographic location and soil conditions that favor the awl nematode, Dolichodorus heterocephalus. What crops are damaged?
8. (10 points) What are the characteristics of virus particles vectored by nematodes in the genus Xiphinema? Indicate two virus diseases, the crops affected and the species of Xiphinema that vector each virus.
Return to Nematology 100 Menu