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PCA - Nematodes Questions and Answers
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Describe the relative size of plant feeding nematodes. Ans: Great
variability. Range from 0.25 um to 12 mm in length.
Name five to six life stages of plant-parasitic nematodes. Ans: Egg,
juvenile 1, J2, J3, J4, adult
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Shape and size of root-knot nematode Ans: Females are round and lose
their veriform shape as adults, males retain veriform shape
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Shape and size of cyst nematode Ans: Adult female is swollen, eggs
retained inside of cyst and cyst is left behind after female dies
Shape and size of lesion nematode Ans: Small, needle-like
Describe how nematode shape affects the choice of extraction
method. Ans: Larger nematodes that are swollen may be observed on
the root system, but smaller nematodes require actual extraction.
Define veriform. Ans: Worm-shaped
Describe the major difference between the veriform stage and other
nematode life stages. Ans: Veriform stages are mobile, swollen stages
are not.
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Describe the feeding apparatus of plant-parasitic nematodes and how it
is used to feed on plants. Ans: Stylet is used to feed. It pierces the plant,
and draws nutrients from the plant.
List two groups of nematodes by common name that exhibit sexual
dimorphism. Ans: Cyst and root-knot nematodes
Describe the differences in shape between males and females in
nematodes that exhibit sexual dimorphism. Ans: Males are veriform,
whereas females are swollen.
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Describe how nematodes move. Ans: Nematodes move with snake-like
movements in short distances. For long distances, they move with
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infected material, water, and equipment.
List the major environmental/ecological factors that influence the time it
takes a nematode to complete its life cycle. Ans: Temperature, moisture,
availability of food from the host.
Identify the host(s) of some non-plant parasitic nematodes. Ans: Animals,
humans, insects
Ectoparasite Ans: Nematode that feeds on the outside of the plant.
Endoparasite Ans: Nematode that feeds on the inside of the plant.
List three ways ectoparasitic and endoparasitic species differ. Ans:
Ectoparasites move to different plants.
Endoparasites move inside the plant tissue.
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Ectoparastites are sampled from the soil, endoparasites are sampled
from the plant.
Identify by genus and common name the major ectoparasitic
nematode groups. Ans: Xiphinema spp. - Dagger
Belonolaimus spp. - Sting
Trichodorus spp. - Stubby-root
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Longidorus spp. - Needle
Paratylenchus spp. - Pin
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Criconemoides & Mesocriconema spp. - Ring
Helicotylenchus & Rotylenchus spp. - Spiral
Tylenchorhynchus spp. - Stunt
Identify by genus and common name the major endoparasitic
nematode groups. Ans: Meloidogyne spp. - Root-knot
Heterodera & Globodera spp. - Cyst
Pratylenchus spp. - Lesion
Radopholus spp. - Burrowing
Rotylenchulus reniformis - reniform
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List the two most economically important species of root-lesion
nematodes on perennial crops in California by genus and species. Ans:
Pratylenchus vulnus & Pratylenchus penetrans
List the two economically important cyst nematodes in California by
genus and species. Ans: Heterodera schachtii & Heterodera cruciferae
List five major root-knot nematodes in California by genus and species.
Ans: Meloidogyne Incognita (southern)
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M. hapla (northern)
M. javanica (Javanese)
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M. arenaria (peanut)
M. chitwoodi (columbia)
M. naasi (barley)
Egg laying habits of ectoparasitic nematodes Ans: Eggs are laid singly in
the soil around the roots, and females may lay up to 2,800 eggs
Egg laying habits of root-lesion nematodes. Ans: Female lays one to two
eggs a day for many days
Egg laying habits of stem and bulb nematodes. Ans: After fertilization by
a male, a female lays up to 10 eggs a day within host tissue and up to
500 eggs in a lifetime.
1
PCA - Nematodes Questions and Answers
(100% Correct Answers) Already Graded A+
Describe the relative size of plant feeding nematodes. Ans: Great
variability. Range from 0.25 um to 12 mm in length.
Name five to six life stages of plant-parasitic nematodes. Ans: Egg,
juvenile 1, J2, J3, J4, adult
© 2026 Assignment Expert
Shape and size of root-knot nematode Ans: Females are round and lose
their veriform shape as adults, males retain veriform shape
Guru01 - Stuvia
Shape and size of cyst nematode Ans: Adult female is swollen, eggs
retained inside of cyst and cyst is left behind after female dies
Shape and size of lesion nematode Ans: Small, needle-like
Describe how nematode shape affects the choice of extraction
method. Ans: Larger nematodes that are swollen may be observed on
the root system, but smaller nematodes require actual extraction.
Define veriform. Ans: Worm-shaped
Describe the major difference between the veriform stage and other
nematode life stages. Ans: Veriform stages are mobile, swollen stages
are not.
,For Expert help and assignment handling,
2
Describe the feeding apparatus of plant-parasitic nematodes and how it
is used to feed on plants. Ans: Stylet is used to feed. It pierces the plant,
and draws nutrients from the plant.
List two groups of nematodes by common name that exhibit sexual
dimorphism. Ans: Cyst and root-knot nematodes
Describe the differences in shape between males and females in
nematodes that exhibit sexual dimorphism. Ans: Males are veriform,
whereas females are swollen.
© 2026 Assignment Expert
Describe how nematodes move. Ans: Nematodes move with snake-like
movements in short distances. For long distances, they move with
Guru01 - Stuvia
infected material, water, and equipment.
List the major environmental/ecological factors that influence the time it
takes a nematode to complete its life cycle. Ans: Temperature, moisture,
availability of food from the host.
Identify the host(s) of some non-plant parasitic nematodes. Ans: Animals,
humans, insects
Ectoparasite Ans: Nematode that feeds on the outside of the plant.
Endoparasite Ans: Nematode that feeds on the inside of the plant.
List three ways ectoparasitic and endoparasitic species differ. Ans:
Ectoparasites move to different plants.
Endoparasites move inside the plant tissue.
,For Expert help and assignment handling,
3
Ectoparastites are sampled from the soil, endoparasites are sampled
from the plant.
Identify by genus and common name the major ectoparasitic
nematode groups. Ans: Xiphinema spp. - Dagger
Belonolaimus spp. - Sting
Trichodorus spp. - Stubby-root
© 2026 Assignment Expert
Longidorus spp. - Needle
Paratylenchus spp. - Pin
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Criconemoides & Mesocriconema spp. - Ring
Helicotylenchus & Rotylenchus spp. - Spiral
Tylenchorhynchus spp. - Stunt
Identify by genus and common name the major endoparasitic
nematode groups. Ans: Meloidogyne spp. - Root-knot
Heterodera & Globodera spp. - Cyst
Pratylenchus spp. - Lesion
Radopholus spp. - Burrowing
Rotylenchulus reniformis - reniform
, For Expert help and assignment handling,
4
List the two most economically important species of root-lesion
nematodes on perennial crops in California by genus and species. Ans:
Pratylenchus vulnus & Pratylenchus penetrans
List the two economically important cyst nematodes in California by
genus and species. Ans: Heterodera schachtii & Heterodera cruciferae
List five major root-knot nematodes in California by genus and species.
Ans: Meloidogyne Incognita (southern)
© 2026 Assignment Expert
M. hapla (northern)
M. javanica (Javanese)
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M. arenaria (peanut)
M. chitwoodi (columbia)
M. naasi (barley)
Egg laying habits of ectoparasitic nematodes Ans: Eggs are laid singly in
the soil around the roots, and females may lay up to 2,800 eggs
Egg laying habits of root-lesion nematodes. Ans: Female lays one to two
eggs a day for many days
Egg laying habits of stem and bulb nematodes. Ans: After fertilization by
a male, a female lays up to 10 eggs a day within host tissue and up to
500 eggs in a lifetime.
