Nematology 100 FINAL EXAM

December 6, 2010 2 hours

(100 points total;       50% of overall grade)



1.  (15 points)

What factors will you consider in developing crop rotation strategies for nematode groups with different feeding habits and life history strategies? 

Discuss the utility and constraints of crop rotation for management of the genus Pratylenchus and the genus Globodera.



2.  (10 points)

Compare and contrast the development and characteristics of the feeding sites incited by Heterodera and Meloidogyne.


3.  (12 points)

Briefly describe the modes of parasitism of the fungi that are antagonistic to nematodes. Provide examples where possible.  Suggest approaches for enhancing the abundance and activity of these fungi in soil.


4.  (16 points)

Based on your knowledge of nematode control, biology, distribution and host ranges, list control measures that are available and practical for the following nematode-host associations? (short answers please):

a)  the potato rot nematode, Ditylenchus destructor, on potato

b)  the foliar nematode, Aphelenchoides ritzemabosi, on chrysanthemum

c)  the root lesion nematode, Pratylenchus vulnus, on roses

d)  the pine wood nematode, Bursaphelenchus xylophilus, in pine trees.


5.  (12 points)
What strategies are available for management of nematodes in a walnut orchard?
Consider options before planting as well as for orchards with established trees.


6.  (5 points)


Using the associated letter(s) in the list on the right, indicate which descriptors apply to the nematicides below (there may be more than one answer)


a) halogenated hydrocarbons

b) fumigants

c) nonfumigants

d) organophosphates

e) carbamates


Telone II (1,3-dichloropropene)


Temik 10G (aldicarb)


Vapam (methyl isothiocyanate)


Furadan (carbofuran)





7.  (10 points)

As a member of a technical advisory committee to the California Department of Food and Agriculture, what actions would you recommend if infestations of the burrowing nematode, Radopholus similis, were found in three newly-planted citrus orchards in southern California?


8.  (10 points)




True (T)


False (F)


Mesocriconema xenoplax, a ring nematode, feeds on roots of woody perennials and is associated with increased severity of bacterial canker in peach.



Soil fumigants such as 1,3-Dichloropropene (Telone) move through the air spaces in soil much faster than through water.



Anguina agrostis is sometimes associated with a bacterial infection of grasses caused by Clavibacter.



The potato cyst nematode recently discovered in Idaho, Globodera pallida, is widely distributed in California.



Genes conferring resistance in plants to soil nematodes have been found most commonly for nematodes like Tylenchorhynchus that are not usually very damaging to crops.



Males of the reniform nematode, Rotylenchulus reniformis and the citrus nematode, Tylenchulus semipenetrans complete several developmental stages without feeding.



Nematophagous fungi are present in many soils but may be below suppressive levels.



Two of the characters indicating relationships of Nematoda with other phyla of animals are that they are segmented and coelomate.



Nematode-virus relationships are non-specific and a nematode such as Longidorus elongatus will vector all strains of Tobacco Rattle virus.



Migratory endoparasites like lesion nematodes are often found in the soil and may also feed ectoparasitically.



9.  (10 points)

Design an experiment to test whether two soils have biological suppressiveness to nematodes and whether they differ in their levels of suppressiveness.  Explain how you will measure and calculate the levels of suppressiveness.