FINAL98.HLP                                                 Rev 5/99

FINAL EXAM              December 16, 1998           2 hours 
(100 points total;  50% of overall grade)

1.  (10 points)
Discuss the impact and factors affecting the efficacy of soil solarization 

2.  (24 points)
Based on your knowledge of nematode control, biology, distribution, host ranges,
and environmental conditions, what control measures are available and practical 
for the following nematode problems:

a)  Globodera rostochiensis on potatoes in Europe

b)  Meloidogyne incognita on tomato in greenhouses

c)  Ditylenchus destructor on peanut in South Africa

d)  Aphelenchoides fragariae on ferns in a botanical garden

e)  Ditylenchus dipsaci on alfalfa in California

f)  Anguina tritici on wheat in India

g)  Bursaphelenchus cocophilus on oil palm in Equador

h)  Tylenchulus semipenetrans on citrus in southern California

3.  (10 points)
Indicate, by placing an ‘X’ in the cell, which of the nematicides in the 
column satisfy the description in the header row.  Note, there may be more than 
‘X’ in any column or row.

Header row:
halogenated hydrocarbon
methylisothiocyanate source
fermentation product

Left column:
Temik 10G
Methyl bromide

4.  (10 points)
List some animal predators of nematodes and indicate their phyla.  
Briefly discuss your view of the potential of each of these organisms as a 
control agent in the tomato cropping system of Yolo county.

5.  (9 points)
Ditylenchus dipsaci, Ditylenchus destructor, and Ditylenchus angustus are 
parasites of plants.  Name at least one host plant of each and indicate the part
the plant where you would expect to find each of the nematode species.

6.  (12 points)
Compare life-history strategies and feeding site establishment of Meloidogyne 
and Heterodera spp. in relation to their importance in cropping systems.

7.  (5 points)
Match the following by placing the appropriate letter in the first column:

Name(s)         Event/Contribution

Hewitt, Raski, and Goheen
A  1913-1932 leader in  nematology in U.S.

Sydney Brenner
B  cyst nematode on sugarbeet in Germany in 1859

Benjamin G. Chitwood 
C  attached rnase gene to a specific promoter for Meloidogyne control.

Turbeville Needham
D  separated Meloidogyne spp on the basis of cuticular markings.

Furney A. Todd
E  parasites and predators of nematodes.

H. Schacht
F  first report of transmission of plant viruses by nematodes.

Joseph N. Sasser
G  R6P with F.A.T.!.

Opperman and Conklin
H  noted anhydrobiotic Anguina tritici becoming active in H2O

Nathanial A. Cobb
G  initiated the research effort on Caenorhabditis elegans

Bruce A. Jaffee
I  Separated Meloidogyne spp on the basis of host differentials

8.  (10 points)
Preliminary experiments indicate that yields, and consequently the crop value, 
sweet corn are diminished by Longidorus africanus as follows:

population level    crop value ($/acre)
        0               1000
        10              950
        20              900
        30              850
        40              800
        50              750
        60              700
Estimate the lowest population density at which the use of a nematicide 
costing $125/acre is profitable.
Assume that the nematicide reduces the population level to zero so that maximum 
crop value is attained after treatment.

9.  (10 points)
Describe the life cycle of a plant-parasitic nematode that is vectored by an 

Nem100 Final, 1998	                                                             
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