2025 PCA WEEDS PRACTICE TEST GUIDE EXAM QUESTIONS WITH
ANSWERS GUARANTEE A+ 2025/2026
Function of root hairs - these structures increase the surface area of the roots so that
they can absorb water efficiently
Function of root tip (meristem) - Point of active cell division within roots
Function of stomata - controls the entering and exiting of gases
Describe the conditions necessary for weed seeds to germinate - Adequate water, light,
temperature
Compare how differing weed germination requirements affect management decisions. -
Seedlings are most vulnerable, so different germination requirements will influence the
management decision as to which method of germination will be used pre- or post-plant
Define seed dormancy - State in which viable seeds do not germinate. Seeds have to
break dormancy before germination.
Describe some factors that regulate or break seed dormancy - Scarification/penetration
of hard seed coat, chemical inhibition, temperature
Describe the effect of seed size on dormancy and the depth from which a weed seed
can successfully germinate. - Larger seed can germinate from deeper depths. Smaller
seed can germinate from shallow depths.
Smaller seed is more persistent than larger seed and can remain dormant for longer
periods of time.
Annual Weed - Weed plant that completes its life cycle in 1 year
Perennial Weed - Weed that persists in the community by continuing to grow year after
year
Biennial Weed - Weed that completes its life cycle in 2 years
Summer Annual Weed - Weeds that germinate in the spring or early summer, grow
through summer, flower and set seed by autumn.
Winter Annual Weed - Weeds that germinate in fall or early winter, grow during the
winter or spring, and flower and usually set seed by early to mid-summer
Dicot - Plants with two cotyledons. Generally have net venation and flower parts are
usually found in multiples of four or five.
,Monocot - Plants with a single seed leaf. Most have leaves with parallel venation and
flower parts occurring in multiples of three
Describe the influence of seasonal changes on the weed spectrum - Different seasons
will see different groups of weeds present in fields (winter vs summer annuals)
Describe the influence of weed growth on water and nutrient availability to the crop. -
Weeds will out-compete crops for water and nutrient availability, hence why it is
important to manage weeds before they become out of control.
Describe the influence of temperature on plant growth. - Warmer temperatures will lead
to increased plant growth but too hot of temperatures can damage plants and retard
their growth
Recognize the importance of light and space in plant growth and development - Plants
need space from other plants as well as adequate light to grow and develop
Reproductive capability of weeds - Weeds can produce seed which can be dispersed
across space, or they can produce propagules which make them very persistent and
difficult to manage
Seeds are only way for annuals and biennials to reproduce.
Propagules are how perennials reproduce and allow for recovery from mechanical
damage.
Describe the mechanisms by which weed seeds are disseminated. - Weed seeds can
be dispersed naturally by wind, water, and animals. They can also be dispersed via
tumbling weeds. They can also be dispersed by humans such as on equipment, in soil
on equipment, or seeds that puncture tires.
Describe how biotic factors of the environment contribute to regulating the seed bank
and seed longevity. - Natural decay can break seed dormancy which if left unmanaged
can replenish the seed bank. Biotic factors can replenish the weed seed bank.
Describe how loss of seed viability contributes to regulating the seed bank and seed
longevity. - Loss of seed viability reduces the amount of weeds that are able to
germinate and reproduce more seed. If a seed bank were to theoretically become
unviable, there would be no weed problems.
Describe how production practices, such as applications of preemergence herbicides,
contribute to regulating the seed bank and seed longevity. - Preemergence herbicides
can reduce the amount of weeds that emerge and have the potential to set seed, thus
reducing the seed bank as well as seed longevity.
Describe how cultural practices contribute to regulating the seed bank and seed
longevity. - Cultural practices, such as preirrigation or crop rotation, can reduce the
, seed bank and longevity by germinating weed seeds to be cultivated, or rotating to a
crop that outcompetes the current weed seeds.
Describe how different types of vegetative propagules spread. - When weeds with
vegetative propagules are fragmented, they can be spread to different fields or parts of
the field.
Describe how to map a field in relationship to weed management considerations. - A
field should be mapped to show what weeds are present, where the weeds are present,
how many weeds are present, and if there are any factors that will influence the choice
of management (water sources, sensitive sites, etc)
List information necessary to document a field's weed history - Cropping history, weeds
prevalent, areas of high weed pressure
Absolute sampling - Sampling to count every individual in a given area
Relative sampling - Sampling to give an estimate of a total population by sampling a
proportion of a population in a given area
Random sampling patterns - Every sample unit has an equal chance of selection
Stratified sampling patterns - Partitions the habitat into subunits that may vary in
character, each subunit is then independently sampled
Systematic sampling patterns - Each sample unit is chosen systematically from a
randomly selected starting point, such as every 50th plant or every 5 feet.
Identify essential times during which monitoring should be done for annual weeds -
Winter annuals during fall and winter, summer annuals during spring and summer
Identify essential times during which monitoring should be done for perennial weeds - At
all times aware that some species are dormant during some seasons
Define biological control - Use of organism or byproducts of living organisms to
suppress or kill pests
Describe and give an example of biological weed control using arthropods. - -Gall
forming mite (Aceria chondrillae) on rush skeletonweed
-Tetranychus lintearius to control gorse
-Cinnabar moth (Tyria jacobaea) on tansy ragwort
-Ragwort seed fly (Botanophila seneciella) on tansy ragwort
-Ragwort flea beetle (Longistarsus jacobaeae) on tansy ragwort
-Klamath weed beetle (Chrysolina quadrigemina) on Klamath weed/St. Johnswort
ANSWERS GUARANTEE A+ 2025/2026
Function of root hairs - these structures increase the surface area of the roots so that
they can absorb water efficiently
Function of root tip (meristem) - Point of active cell division within roots
Function of stomata - controls the entering and exiting of gases
Describe the conditions necessary for weed seeds to germinate - Adequate water, light,
temperature
Compare how differing weed germination requirements affect management decisions. -
Seedlings are most vulnerable, so different germination requirements will influence the
management decision as to which method of germination will be used pre- or post-plant
Define seed dormancy - State in which viable seeds do not germinate. Seeds have to
break dormancy before germination.
Describe some factors that regulate or break seed dormancy - Scarification/penetration
of hard seed coat, chemical inhibition, temperature
Describe the effect of seed size on dormancy and the depth from which a weed seed
can successfully germinate. - Larger seed can germinate from deeper depths. Smaller
seed can germinate from shallow depths.
Smaller seed is more persistent than larger seed and can remain dormant for longer
periods of time.
Annual Weed - Weed plant that completes its life cycle in 1 year
Perennial Weed - Weed that persists in the community by continuing to grow year after
year
Biennial Weed - Weed that completes its life cycle in 2 years
Summer Annual Weed - Weeds that germinate in the spring or early summer, grow
through summer, flower and set seed by autumn.
Winter Annual Weed - Weeds that germinate in fall or early winter, grow during the
winter or spring, and flower and usually set seed by early to mid-summer
Dicot - Plants with two cotyledons. Generally have net venation and flower parts are
usually found in multiples of four or five.
,Monocot - Plants with a single seed leaf. Most have leaves with parallel venation and
flower parts occurring in multiples of three
Describe the influence of seasonal changes on the weed spectrum - Different seasons
will see different groups of weeds present in fields (winter vs summer annuals)
Describe the influence of weed growth on water and nutrient availability to the crop. -
Weeds will out-compete crops for water and nutrient availability, hence why it is
important to manage weeds before they become out of control.
Describe the influence of temperature on plant growth. - Warmer temperatures will lead
to increased plant growth but too hot of temperatures can damage plants and retard
their growth
Recognize the importance of light and space in plant growth and development - Plants
need space from other plants as well as adequate light to grow and develop
Reproductive capability of weeds - Weeds can produce seed which can be dispersed
across space, or they can produce propagules which make them very persistent and
difficult to manage
Seeds are only way for annuals and biennials to reproduce.
Propagules are how perennials reproduce and allow for recovery from mechanical
damage.
Describe the mechanisms by which weed seeds are disseminated. - Weed seeds can
be dispersed naturally by wind, water, and animals. They can also be dispersed via
tumbling weeds. They can also be dispersed by humans such as on equipment, in soil
on equipment, or seeds that puncture tires.
Describe how biotic factors of the environment contribute to regulating the seed bank
and seed longevity. - Natural decay can break seed dormancy which if left unmanaged
can replenish the seed bank. Biotic factors can replenish the weed seed bank.
Describe how loss of seed viability contributes to regulating the seed bank and seed
longevity. - Loss of seed viability reduces the amount of weeds that are able to
germinate and reproduce more seed. If a seed bank were to theoretically become
unviable, there would be no weed problems.
Describe how production practices, such as applications of preemergence herbicides,
contribute to regulating the seed bank and seed longevity. - Preemergence herbicides
can reduce the amount of weeds that emerge and have the potential to set seed, thus
reducing the seed bank as well as seed longevity.
Describe how cultural practices contribute to regulating the seed bank and seed
longevity. - Cultural practices, such as preirrigation or crop rotation, can reduce the
, seed bank and longevity by germinating weed seeds to be cultivated, or rotating to a
crop that outcompetes the current weed seeds.
Describe how different types of vegetative propagules spread. - When weeds with
vegetative propagules are fragmented, they can be spread to different fields or parts of
the field.
Describe how to map a field in relationship to weed management considerations. - A
field should be mapped to show what weeds are present, where the weeds are present,
how many weeds are present, and if there are any factors that will influence the choice
of management (water sources, sensitive sites, etc)
List information necessary to document a field's weed history - Cropping history, weeds
prevalent, areas of high weed pressure
Absolute sampling - Sampling to count every individual in a given area
Relative sampling - Sampling to give an estimate of a total population by sampling a
proportion of a population in a given area
Random sampling patterns - Every sample unit has an equal chance of selection
Stratified sampling patterns - Partitions the habitat into subunits that may vary in
character, each subunit is then independently sampled
Systematic sampling patterns - Each sample unit is chosen systematically from a
randomly selected starting point, such as every 50th plant or every 5 feet.
Identify essential times during which monitoring should be done for annual weeds -
Winter annuals during fall and winter, summer annuals during spring and summer
Identify essential times during which monitoring should be done for perennial weeds - At
all times aware that some species are dormant during some seasons
Define biological control - Use of organism or byproducts of living organisms to
suppress or kill pests
Describe and give an example of biological weed control using arthropods. - -Gall
forming mite (Aceria chondrillae) on rush skeletonweed
-Tetranychus lintearius to control gorse
-Cinnabar moth (Tyria jacobaea) on tansy ragwort
-Ragwort seed fly (Botanophila seneciella) on tansy ragwort
-Ragwort flea beetle (Longistarsus jacobaeae) on tansy ragwort
-Klamath weed beetle (Chrysolina quadrigemina) on Klamath weed/St. Johnswort
