Nematology 100 - Final Exam, 1991 12/91 NEMATOLOGY 100 - FINAL EXAM December 12, 1991 2 hours (12 points) 1. Provide three examples of plant-parasitic nematode species for which resistance to desiccation is an important survival mechanism. What life stages are involved, and what are the feeding habits of the nematodes? Briefly describe the economic significance and potential management approaches in each case. (10 points) 2. Describe the development of the feeding site in the genera Globodera and Meloidogyne. What are the sources of the stimuli in the nematodes? (12 points) 3. Briefly discuss the economic importance, distribution, host range, injury to host, relation to host tissue, and management, of the following: a. Pratylenchus vulnus. b. Hirschmanniella oryzae. c. Heterodera glycines. (10 points) 4. Describe the proposed causality of bacterial canker of Prunus spp. (almonds and peaches), in California. What biological and environmental factors seem to play a role in the disease? (10 points) 5. What factors will you consider in developing crop rotation for various plant-parasitic nematode species? Discuss the use of this approach for the citrus nematode, Tylenchulus semipenetrans, and the sugar beet cyst nematode, Heterodera schachtii. (15 points) 6. Based on your knowledge of nematode management tactics, biology, distribution and host ranges, what control measures are available and practical for the following nematode/crop combinations: a) Globodera rostochiensis on potatoes b) Meloidogyne incognita on grape c) Anguina tritici on wheat d) Paratrichodorus minor on cotton e) Xiphinema index on grape (11 points) 7. What effects effects might cover crops have on populations of plant-parasitic nematodes. (10 points) 8. If Radopholus similis was found attacking citrus trees in two groves in southern California, what measures would you take if you were an official charged with enforcing regulatory laws. (10 points) 9. Describe the interaction of organisms that results in the condition called 'staggers' in sheep in Australia.