PCA – NEMATODES EXAM: 100% EXPERT VERIFIED
STUDY GUIDE REAL TESTING 2026|2027 QUESTIONS
DETAILED ANSWERS AND INSTRUCTOR NOTE FOR A+
GUARANTEED PASS
Define damage threshold. - Answers -Level at which the pest is expected to damage the crop
Describe the factors that influence the damage threshold for nematodes. - Answers -
Temperature at time of planting
List the resources for finding out methods for controlling nematodes in specific crops. - Answers
-UC IPM Pest Management Guidelines
Describe the role of the California Nursery Certification program in preventing the spread of
nematodes - Answers -Keeps devastating nematodes out of state, certifies nurseries as having
nematode-free stock so that they may sell in California.
List methods used to prevent the spread of nematodes - Answers -Quarantine, certified planting
materials, check suspect materials before planting, nematodes may be present in manure, clean
equipment before moving, avoid contaminated irrigation water
1|Page
,Describe the importance of cleaning equipment to limit the spread of nematodes - Answers -
Nematodes spread among fields mostly by dirty equipment. Cleaning equipment eliminates the
possibility of spread.
Describe the feasibility of eradicating 100% of the nematodes from a field. - Answers -Not
feasible. But, it is feasible to manage nematode problems.
Describe how crop rotations can be used to manage nematode populations - Answers -Rotating
to a non host can help reduce problematic nematode populations
Identify an example of a successful crop rotation program against a nematode pest in California
- Answers -Rotating sugarbeet with tomatoes because of the sugarbeet cyst nematode's narrow
host range
Describe the use of degree-day models and how the manipulation of planting or harvest dates
can be used to limit nematode damage. - Answers -Planting at temperatures colder than
minimum needed for infection can lead to reduced damage. Early harvest may reduce damage
and nematode populations as well. Degree-day models give an indication of when nematodes
will develop into their infections stage of development.
Describe the role of weed control in roration programs for nematode pest management. -
Answers -Weeds are potential hosts for many damaging nematodes, so management of weeds
is important because the program's success depends on the absence of host roots to prevent
nematode reproduction and feeding.
2|Page
,Describe the impact of solarization on nematodes. - Answers -Solarization may have some
success against some nematodes, but nematodes may be so deep that it is not effective.
Describe how soil amendments can be used to reduce nematode damage. - Answers -Some
amendments reduce stress and make nematode damage less severe, some stimulate plant
growth, some stimulate predators of nematodes
Define "replant problem" - Answers -Replant disease affects trees and vines in ground where
perennial crops were previously planted, but it is not known what exactly in the soil causes the
problem.
Describe how cover crops can impact nematode problems. - Answers -Some cover crops may be
hosts or non-hosts of certain nematodes. It is important to know what nematodes are present
as well as if the cover crop is a host before planting.
List four types of organisms known to attack nematodes in the soil. - Answers -Tardigrades,
insects, mites, nematodes
Resistance - Answers -Plant may or may not show damage but is not overwhelmed by nematode
Tolerance - Answers -Plants able to withstand nematode attack
3|Page
, Biotype - Answers -Localized races of nematodes that very in host-range specificity
Differentiate between host resistance and tolerance - Answers -Tolerant hosts can sometimes
show damage, resistant hosts will likely not show damage
List factors that need to be considered when determining whether to plant a nematode
resistant cultivar. - Answers -Which nematodes is cultivar resistant to, will nematodes damage
the cultivar, will nematodes reproduce on the cultivar
Immune plants - Answers -Nematodes do not attack.
Ex: root-knot nematodes completely avoid roots of Blenheim apricots
Susceptible host plants - Answers -Host plant that is prone to attack from nematodes.
Nonhost plants - Answers -Plant is not a host for nematodes
Ex: citrus is a nonhost for root-knot nematodes
4|Page
STUDY GUIDE REAL TESTING 2026|2027 QUESTIONS
DETAILED ANSWERS AND INSTRUCTOR NOTE FOR A+
GUARANTEED PASS
Define damage threshold. - Answers -Level at which the pest is expected to damage the crop
Describe the factors that influence the damage threshold for nematodes. - Answers -
Temperature at time of planting
List the resources for finding out methods for controlling nematodes in specific crops. - Answers
-UC IPM Pest Management Guidelines
Describe the role of the California Nursery Certification program in preventing the spread of
nematodes - Answers -Keeps devastating nematodes out of state, certifies nurseries as having
nematode-free stock so that they may sell in California.
List methods used to prevent the spread of nematodes - Answers -Quarantine, certified planting
materials, check suspect materials before planting, nematodes may be present in manure, clean
equipment before moving, avoid contaminated irrigation water
1|Page
,Describe the importance of cleaning equipment to limit the spread of nematodes - Answers -
Nematodes spread among fields mostly by dirty equipment. Cleaning equipment eliminates the
possibility of spread.
Describe the feasibility of eradicating 100% of the nematodes from a field. - Answers -Not
feasible. But, it is feasible to manage nematode problems.
Describe how crop rotations can be used to manage nematode populations - Answers -Rotating
to a non host can help reduce problematic nematode populations
Identify an example of a successful crop rotation program against a nematode pest in California
- Answers -Rotating sugarbeet with tomatoes because of the sugarbeet cyst nematode's narrow
host range
Describe the use of degree-day models and how the manipulation of planting or harvest dates
can be used to limit nematode damage. - Answers -Planting at temperatures colder than
minimum needed for infection can lead to reduced damage. Early harvest may reduce damage
and nematode populations as well. Degree-day models give an indication of when nematodes
will develop into their infections stage of development.
Describe the role of weed control in roration programs for nematode pest management. -
Answers -Weeds are potential hosts for many damaging nematodes, so management of weeds
is important because the program's success depends on the absence of host roots to prevent
nematode reproduction and feeding.
2|Page
,Describe the impact of solarization on nematodes. - Answers -Solarization may have some
success against some nematodes, but nematodes may be so deep that it is not effective.
Describe how soil amendments can be used to reduce nematode damage. - Answers -Some
amendments reduce stress and make nematode damage less severe, some stimulate plant
growth, some stimulate predators of nematodes
Define "replant problem" - Answers -Replant disease affects trees and vines in ground where
perennial crops were previously planted, but it is not known what exactly in the soil causes the
problem.
Describe how cover crops can impact nematode problems. - Answers -Some cover crops may be
hosts or non-hosts of certain nematodes. It is important to know what nematodes are present
as well as if the cover crop is a host before planting.
List four types of organisms known to attack nematodes in the soil. - Answers -Tardigrades,
insects, mites, nematodes
Resistance - Answers -Plant may or may not show damage but is not overwhelmed by nematode
Tolerance - Answers -Plants able to withstand nematode attack
3|Page
, Biotype - Answers -Localized races of nematodes that very in host-range specificity
Differentiate between host resistance and tolerance - Answers -Tolerant hosts can sometimes
show damage, resistant hosts will likely not show damage
List factors that need to be considered when determining whether to plant a nematode
resistant cultivar. - Answers -Which nematodes is cultivar resistant to, will nematodes damage
the cultivar, will nematodes reproduce on the cultivar
Immune plants - Answers -Nematodes do not attack.
Ex: root-knot nematodes completely avoid roots of Blenheim apricots
Susceptible host plants - Answers -Host plant that is prone to attack from nematodes.
Nonhost plants - Answers -Plant is not a host for nematodes
Ex: citrus is a nonhost for root-knot nematodes
4|Page
