Nematology 100 Name:

MID-TERM EXAM, 11/03/99

90 minutes

1. (25 points)

You are provided with nematodes extracted from roots of plants lining an irrigation ditch in Solano County.

a. Place an adult female plant-parasitic nematode of any species on a microscope slide.

Kill the nematode with gentle heat.

Apply a coverslip.

Seal the edge of the coverslip with fingernail polish to prevent the slide from drying out.

Place the slide on the compound microscope and adjust the microscope to provide Köhler illumination.

b. Indicate on your exam sheet the Class and Order of your nematode.

c. Draw and label the component parts of the stylet and esophagus for this type of nematode (either from your specimen, or from your knowledge of anatomy and morphology, or both).

d. Call the instructor for examination of your nematode. If there is more than one nematode present in the microscope field, indicate the specimen you wish to have examined. Do not ask or expect the instructor to make the selection.

Only the nematode that you indicate initially will be considered.


adult female plant-parasite, good condition 15 pts

non-parasite, good condition 8 pts

correct designation of Class and Order 2 pts

correct drawing and identification of stylet/esophagus 8 pts

points off for damage, distortion, dry slides, etc.



2. (15 points)

Describe, with the aid of drawings, the components of the male reproductive system of tylenchid nematodes.

Briefly describe the function of each structure.


3. (10 points)

a. Describe the geographic distribution and soil conditions that favor the sting nematode, Belonolaimus longicaudatus.

b. Does it occur in California?

c. Which crops are damaged?

d. What is the feeding habit of this nematode?



4. (10 points)

Compare general anatomical characteristics of stoma and esophageal structures of endoparasitic and ectoparasitic plant-feeding nematodes.



5. (20 points)

a) Sketch the anterior portion of three nematode genera that are vectors of viruses.

b) Identify each genus drawn.

c) List the particle type and virus classification for each genus.

Indicate the location of the virus in the nematode

Describe persistence or transmission of the virus across various stages of the nematode lifecycle.

f) (i) Name a nematode vectored virus disease in California.

(ii) Name the vector.

(iii) Name the plant host.

(iv) In what general group is this type of virus classified?



6. (10 points)

In the table below, provide the following information for each of the nematodes listed (answer by using the appropriate letter).

(i) Order: a) Tylenchida,

b) Rhabditida,

c) Diplogasterida,

d) Dorylaimida.

(ii) Esophagus type a) tylenchid - butting,

b) tylenchid - overlapping,

            c) dorylaimid.

(iii) Ovaries a) one,

b) two,

c)more than two.

(iv) Virus vector? a)no,


(v) Adult female feeding habit a) migratory ectoparasite,

         b) migratory endoparasite,

c) sedentary endoparasite.

(vi) Provide a recognized common name.



Tylenchorhynchus claytoni

Hemicycliophora arenaria

Paratrichodorus minor

Virus vector?      
Feeding habit?      
Common name?      


7. (10 points)

Discuss factors that contribute to bacterial canker of peach in California.