PCA Nematodes Exam 10th Edition with verified
questions and answers
Describe why ectoparasitic nematodes are not found in root samples. -
Answers-They spend their entire lives outside of roots in the soil, so they
will be found in soil samples.
Describe why root-knot nematodes may not be found in a root sample that
has nematode galls on it - Answers-Dagger and needle nematodes also
produce root galling, so root galls caused by nematodes are not always
caused by root-knot nematodes.
List the common units used to report nematode population levels from soil
and from roots. - Answers-Basis of a volume or weight of soil, or weight of
plant tissue.
Describe the factors that influence the efficiency of the extraction method. -
Answers-Size of soil particles, organic matter content and size, shape and
motility of nematode, and capability of the technician
Explain extraction efficiency and its importance in nematode sampling. -
Answers-Indicates percentage of nematodes recovered from a sample to
which a known number of nematodes has been added.
Identify the different extraction methods used by labs. - Answers-Sieving,
Fenwick Can, Elutriator, Baermann Funnel, Mist, Sugar Flotation, Sugar
Centrifugation, Staining Roots, Greenhouse Bioassay
,List the preferred extraction method for nematodes of foliage or stems -
Answers-Baermann funnel, mist chambers
List the preferred extraction method for dagger nematodes - Answers-
Baermann funel, Sugar flotation and Centrifugation
List the preferred extraction method for cyst nematodes - Answers-Sugar
flotation and centrigufation, Baermann funnel
List factors to consider in conjunction with every nematode sample -
Answers-Suitability of sample, efficiency of extraction method,
pathogenicity of nematodes present, biological and environmental factors
that might influence pathogenicity
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
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.
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
questions and answers
Describe why ectoparasitic nematodes are not found in root samples. -
Answers-They spend their entire lives outside of roots in the soil, so they
will be found in soil samples.
Describe why root-knot nematodes may not be found in a root sample that
has nematode galls on it - Answers-Dagger and needle nematodes also
produce root galling, so root galls caused by nematodes are not always
caused by root-knot nematodes.
List the common units used to report nematode population levels from soil
and from roots. - Answers-Basis of a volume or weight of soil, or weight of
plant tissue.
Describe the factors that influence the efficiency of the extraction method. -
Answers-Size of soil particles, organic matter content and size, shape and
motility of nematode, and capability of the technician
Explain extraction efficiency and its importance in nematode sampling. -
Answers-Indicates percentage of nematodes recovered from a sample to
which a known number of nematodes has been added.
Identify the different extraction methods used by labs. - Answers-Sieving,
Fenwick Can, Elutriator, Baermann Funnel, Mist, Sugar Flotation, Sugar
Centrifugation, Staining Roots, Greenhouse Bioassay
,List the preferred extraction method for nematodes of foliage or stems -
Answers-Baermann funnel, mist chambers
List the preferred extraction method for dagger nematodes - Answers-
Baermann funel, Sugar flotation and Centrifugation
List the preferred extraction method for cyst nematodes - Answers-Sugar
flotation and centrigufation, Baermann funnel
List factors to consider in conjunction with every nematode sample -
Answers-Suitability of sample, efficiency of extraction method,
pathogenicity of nematodes present, biological and environmental factors
that might influence pathogenicity
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
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.
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
