Nematology 100                                             Name:

MID-TERM EXAM, 10/27/2010

90 minutes

1. (25 points)

You are provided with a smorgasbord of nematodes extracted from soil around the roots of plants.

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

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

d. Which of the morphological and anatomical characteristics of the specimens suggest that the nematodes feed as ectoparasites?

Which characteristics suggest that they feed as endoparasites? 

e. 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 expect the instructor to make the selection.

Only the nematodes that you indicate initially will be considered.

Grading:

• adult female plant-parasite, good condition                    10 pts
• adult male plant-parasite, good condition                         4 pts
  • or, juvenile or non-parasite, good condition           3 pts
• correct designation of Class and Order                            3 pts
• reasonable justification of feeding habit designation        4 pts
• correct drawing and identification of esophagus

         and reproductive structures                                           8 pts

• points off for damage, distortion, dry slides, microscope not in Köhler illumination, etc.

 2.  (15 points) 

What is the function of the following structures in  nematodes?

            a)  Gubernaculum
     

b)  Phasmids

            c)  Odontophore

            d)  Amphids

           e)  Spermatheca

            f)  Postcorpus of the esophagus in Tylenchida

 g)  Labial papillae

h)  Cloaca

3. (10 points)

List six diagnostic characteristics of the Phylum Nematoda.

4.  (20 points)

Provide the following information for each of the nematodes in the lower box.  Answer by using the appropriate letter.

(i)

Order

(ii)

Esophagus type

(iii)

Number of ovaries (female):

(iv)

Vector of a plant virus?

(v)

Adult female feeding habit

a)    Tylenchida

b)    Rhabditida

c)    Diplogastrida

d)  Dorylaimida

a) tylenchid - butting,

b) tylenchid - overlapping,

c) dorylaimid

a) one

b) two

c) more than two

d) none

a) no

b) yes

a) migratory ectoparasite,    

b) migratory endoparasite,

c) sedentary endoparasite

Belonolaimus longicaudatus

(sting nematode)

Pratylenchus penetrans

(root lesion nematode)

Paratylenchus hamatus

(pin nematode)

Hirschmanniella oryzae

(rice root nematode)

(i)

(i)

(i)

(i)

(ii)

(ii)

(ii)

(ii)

(iii)

(iii)

(iii)

(iii)

(iv)

(iv)

(iv)

(iv)

(v)

(v)

(v)

(v)

 5.  (15 points)                    

       Radopholus similis is an important parasite of bananas in Central America and other tropical areas.

a)    Describe the damage that this nematode causes to the plant root system.

  b)   Describe how this damage translates into crop loss.

c)    What methods are used to eliminate the nematode from planting stock?

d)     What methods are used to minimize the nematode damage in established plantations?

 6. (15 points)

a)  What is the size and shape of Nepoviruses particles?

b)  Provide genera or common names of two nematodes that transmit Nepoviruses.

c)  Describe the symptoms and crop damage caused by grapevine fanleaf virus.  What are the effects of the virus on the vector?

d)  Are plant viruses passed through the nematode egg stage to subsequent generations?

7.  (10 points)

 Describe the feeding process in Paratrichodorus minor (the stubby root nematode).