FINAL95.HLP NEMATOLOGY 100 - FINAL EXAM Name: December 16, 1995 2 hours (50% of overall grade) 1. (10 points) Describe relationships between seed-gall nematodes and bacteria of the genus Clavibacter. What nematodes are involved and which crops are affected. What are the economic consequences? 2. (10 points) What factors will you consider in designing crop rotation strategies for managing plant-parasitic nematodes? Discuss the use of this approach for the management of nematodes in the genus Pratylenchus and the genus Globodera. 3. (10 points) Match the following. (Some letters may be used several times, others may not be used at all. There may be several answers to each question). _________1. Animal parasite a) Caenorhabditis elegans _________2. Plant parasite b) Trichodorus similis _________3. Predator c) Ditylenchus destructor _________4. Bacterial-feeding d) Cephalobus persegnis _________5. Lemon-shaped cysts e) Labronema sp _________6. Virus transmission f) Rotylenchulus reniformis _________7. A-rated pest (California) g) Wuchereria bancrofti _________8. Migratory endoparasite h) Heterodera glycines _________9. Order Tylenchida i) Ascaris suum _________10.Nematode/bacterium interaction j) Pseudomonas solanacearum 4. (12 points) On December 8, 1994 the California Department of Pesticide Regulation announced that permits can be issued in 13 counties for the use of Telone II nematicide. a) What type of nematicide is Telone and how does it move through soil? b) If you were asked to designate three California crops that you considered to have highest priority for use of this nematicide, what would they be, and why? c) What are the target nematode species in the case of each of your designated crops? d) Discuss the pros and cons of using the nematicide in situations where it has not been used for several years. 5. (12 points) What approaches would you take in attempting to increasing the abundance of parasites and predators of nematodes in a soil so that it becomes suppressive to plant-parasitic nematodes? What do you think the probabilitity of success is, and what factors may work against you? 6. (12 points) The following nematodes are detected in a field to be planted to peach in a sandy soil in Merced County, California: two plant-parasitic species - Heterodera schachtii and Meloidogyne incognita, a predaceous nematode- Seinura sp., and at least three species of microbial-feeding nematodes in the family Rhabditidae. Recommend any nematode control procedures that you think appropriate, environmentally sound, and economically justifiable. Indicate the nematodes that you are targeting with each procedure. 7. (10 points) Describe the distribution and life cycle of the dagger nematode, Xiphinema index. 8. (10 points) Describe the life cycle of a plant-parasitic nematode that is vectored by an insect. 9. (4 points) Sexual dimorphism is the description used when a male and female nematode differ morphologically. Sexual dimorphism is found in which of the following genera? Pratylenchus Tylenchulus Meloidogyne Tylenchorhynchus 10. (10 points) Describe the stimuli and responses that result in the syncytial feeding sites of Heterodera and Globodera spp.