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.