PCA NEMATODES EXAM
2026/2027 WITH ACTUAL CORRECT
QUESTIONS AND VERIFIED DETAILED
ANSWERS |CURRENTLY TESTING
QUESTIONS AND SOLUTIONS|ALREADY
GRADED A+|NEWEST |BRAND NEW
VERSION|JUST RELEASED!!
Describe the relative size of plant feeding nematodes.
Great variability. Range from 0.25 um to 12 mm in length.
Name five to six life stages of plant-parasitic nematodes.
Egg, juvenile 1, J2, J3, J4, adult
Shape and size of root-knot nematode
Females are round and lose their veriform shape as adults, males retain veriform shape
Shape and size of cyst nematode
Adult female is swollen, eggs retained inside of cyst and cyst is left behind after female dies
Shape and size of lesion nematode
Small, needle-like
Describe how nematode shape affects the choice of extraction method.
Larger nematodes that are swollen may be observed on the root system, but smaller nematodes
require actual extraction.
Define veriform.
Worm-shaped
1|Page
,Describe the major difference between the veriform stage and other nematode life stages.
Veriform stages are mobile, swollen stages are not.
Describe the feeding apparatus of plant-parasitic nematodes and how it is used to feed on
plants.
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.
Cyst and root-knot nematodes
Describe the differences in shape between males and females in nematodes that exhibit sexual
dimorphism.
Males are veriform, whereas females are swollen.
Describe how nematodes move.
Nematodes move with snake-like movements in short distances. For long distances, they move
with infected material, water, and equipment.
List the major environmental/ecological factors that influence the time it takes a nematode to
complete its life cycle.
Temperature, moisture, availability of food from the host.
Identify the host(s) of some non-plant parasitic nematodes.
Animals, humans, insects
Ectoparasite
Nematode that feeds on the outside of the plant.
Endoparasite
Nematode that feeds on the inside of the plant.
List three ways ectoparasitic and endoparasitic species differ.
2|Page
,Ectoparasites move to different plants.
Endoparasites move inside the plant tissue.
Ectoparastites are sampled from the soil, endoparasites are sampled from the plant.
Identify by genus and common name the major ectoparasitic nematode groups.
Xiphinema spp. - Dagger
Belonolaimus spp. - Sting
Trichodorus spp. - Stubby-root
Longidorus spp. - Needle
Paratylenchus spp. - Pin
Criconemoides & Mesocriconema spp. - Ring
Helicotylenchus & Rotylenchus spp. - Spiral
Tylenchorhynchus spp. - Stunt
Identify by genus and common name the major endoparasitic nematode groups.
Meloidogyne spp. - Root-knot
Heterodera & Globodera spp. - Cyst
Pratylenchus spp. - Lesion
Radopholus spp. - Burrowing
Rotylenchulus reniformis - reniform
List the two most economically important species of root-lesion nematodes on perennial crops
in California by genus and species.
Pratylenchus vulnus & Pratylenchus penetrans
List the two economically important cyst nematodes in California by genus and species.
Heterodera schachtii & Heterodera cruciferae
List five major root-knot nematodes in California by genus and species.
Meloidogyne Incognita (southern)
M. hapla (northern)
3|Page
, M. javanica (Javanese)
M. arenaria (peanut)
M. chitwoodi (columbia)
M. naasi (barley)
Egg laying habits of ectoparasitic nematodes
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.
Female lays one to two eggs a day for many days
Egg laying habits of stem and bulb nematodes.
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.
Egg laying habits of foliar nematodes.
Relatively few eggs laid. 20-30 total eggs has been observed in one species.
Egg laying habits of citrus nematodes
Egg masses of about 100 eggs are deposited into a gelatinous matrix.
Egg laying habits of root-knot nematodes.
Eggs are laid in a gelatinous matrix at posterior end of the body, which may be within the root
partially or completely. Low survival.
Sedentary ectoparasite
Nematodes that feed on the outside of the plant in one location for most of their life cycle.
Ex: Ring Nematode (Criconemella, Macroposthhonia)
Migratory ectoparasite
4|Page
2026/2027 WITH ACTUAL CORRECT
QUESTIONS AND VERIFIED DETAILED
ANSWERS |CURRENTLY TESTING
QUESTIONS AND SOLUTIONS|ALREADY
GRADED A+|NEWEST |BRAND NEW
VERSION|JUST RELEASED!!
Describe the relative size of plant feeding nematodes.
Great variability. Range from 0.25 um to 12 mm in length.
Name five to six life stages of plant-parasitic nematodes.
Egg, juvenile 1, J2, J3, J4, adult
Shape and size of root-knot nematode
Females are round and lose their veriform shape as adults, males retain veriform shape
Shape and size of cyst nematode
Adult female is swollen, eggs retained inside of cyst and cyst is left behind after female dies
Shape and size of lesion nematode
Small, needle-like
Describe how nematode shape affects the choice of extraction method.
Larger nematodes that are swollen may be observed on the root system, but smaller nematodes
require actual extraction.
Define veriform.
Worm-shaped
1|Page
,Describe the major difference between the veriform stage and other nematode life stages.
Veriform stages are mobile, swollen stages are not.
Describe the feeding apparatus of plant-parasitic nematodes and how it is used to feed on
plants.
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.
Cyst and root-knot nematodes
Describe the differences in shape between males and females in nematodes that exhibit sexual
dimorphism.
Males are veriform, whereas females are swollen.
Describe how nematodes move.
Nematodes move with snake-like movements in short distances. For long distances, they move
with infected material, water, and equipment.
List the major environmental/ecological factors that influence the time it takes a nematode to
complete its life cycle.
Temperature, moisture, availability of food from the host.
Identify the host(s) of some non-plant parasitic nematodes.
Animals, humans, insects
Ectoparasite
Nematode that feeds on the outside of the plant.
Endoparasite
Nematode that feeds on the inside of the plant.
List three ways ectoparasitic and endoparasitic species differ.
2|Page
,Ectoparasites move to different plants.
Endoparasites move inside the plant tissue.
Ectoparastites are sampled from the soil, endoparasites are sampled from the plant.
Identify by genus and common name the major ectoparasitic nematode groups.
Xiphinema spp. - Dagger
Belonolaimus spp. - Sting
Trichodorus spp. - Stubby-root
Longidorus spp. - Needle
Paratylenchus spp. - Pin
Criconemoides & Mesocriconema spp. - Ring
Helicotylenchus & Rotylenchus spp. - Spiral
Tylenchorhynchus spp. - Stunt
Identify by genus and common name the major endoparasitic nematode groups.
Meloidogyne spp. - Root-knot
Heterodera & Globodera spp. - Cyst
Pratylenchus spp. - Lesion
Radopholus spp. - Burrowing
Rotylenchulus reniformis - reniform
List the two most economically important species of root-lesion nematodes on perennial crops
in California by genus and species.
Pratylenchus vulnus & Pratylenchus penetrans
List the two economically important cyst nematodes in California by genus and species.
Heterodera schachtii & Heterodera cruciferae
List five major root-knot nematodes in California by genus and species.
Meloidogyne Incognita (southern)
M. hapla (northern)
3|Page
, M. javanica (Javanese)
M. arenaria (peanut)
M. chitwoodi (columbia)
M. naasi (barley)
Egg laying habits of ectoparasitic nematodes
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.
Female lays one to two eggs a day for many days
Egg laying habits of stem and bulb nematodes.
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.
Egg laying habits of foliar nematodes.
Relatively few eggs laid. 20-30 total eggs has been observed in one species.
Egg laying habits of citrus nematodes
Egg masses of about 100 eggs are deposited into a gelatinous matrix.
Egg laying habits of root-knot nematodes.
Eggs are laid in a gelatinous matrix at posterior end of the body, which may be within the root
partially or completely. Low survival.
Sedentary ectoparasite
Nematodes that feed on the outside of the plant in one location for most of their life cycle.
Ex: Ring Nematode (Criconemella, Macroposthhonia)
Migratory ectoparasite
4|Page
