PCA: Weeds Exam Questions and Answers
Verified 100% Correct
What is the major barrier to herbicide entry into plant shoots - ANSWER Epidermis
Under what conditions are weeds seeds most likely to germinate - ANSWER When they
are in a suitable micro environment with both water and light
Weeds that are winter annuals would be best be controlled with - ANSWER A pre-
emergent herbicide in the late summer
How many weed species have seeds with a hard coat or chemical substance in them
that - ANSWER Until broken causes the seed to be dormant
Seeds from annual plants are often produced and reached the soil under adequate
conditions for germination yet do not germinate until the following year why not -
ANSWER Most seeds have some type of primary dormancy which halts immediate
germination
Small weed seeds generally persist longer than large weed seeds because - ANSWER
Small seeds can move deeper into the soil profile preventing germination
Winter annuals are plants that are - ANSWER Non dormant in fall and early winter and
dormant in spring and summer
What two simple molecules are used in photosynthesis to make carbohydrates and
what is the energy source for the mild synthetic process. - ANSWER CO2 & water
, Reproductive capability of weeds is enhanced by - ANSWER Their ability to grow over a
wide range of conditions
Primary methods of weed seed dispersal include all of the following methods except -
ANSWER Spread through vegetative propoguels
Tillage affects the weed seed bank by - ANSWER All of the above
Perennial plants - ANSWER Live longer than two years
A biotype of a weed is a - ANSWER Locally adapted variety of a weed that is genetically
distinct from other population
In rice the repeated use of sulfonylurea herbicides has - ANSWER Monitoring for weeds
would will be less expensive
One pattern of weed sampling that can be taken into account field variation is -
ANSWER Stratified sampling
Classical biological control is achieved through - ANSWER Establishment of self
sustaining populations of exotic natural enemies
Which type of organisms is most commonly used for biological controlled weeds -
ANSWER Arthropods
In order to have a classical biological control program which of the following steps
would be needed - ANSWER The project must be approved by the agricultural
department of the county from which the invasion weed originates
Verified 100% Correct
What is the major barrier to herbicide entry into plant shoots - ANSWER Epidermis
Under what conditions are weeds seeds most likely to germinate - ANSWER When they
are in a suitable micro environment with both water and light
Weeds that are winter annuals would be best be controlled with - ANSWER A pre-
emergent herbicide in the late summer
How many weed species have seeds with a hard coat or chemical substance in them
that - ANSWER Until broken causes the seed to be dormant
Seeds from annual plants are often produced and reached the soil under adequate
conditions for germination yet do not germinate until the following year why not -
ANSWER Most seeds have some type of primary dormancy which halts immediate
germination
Small weed seeds generally persist longer than large weed seeds because - ANSWER
Small seeds can move deeper into the soil profile preventing germination
Winter annuals are plants that are - ANSWER Non dormant in fall and early winter and
dormant in spring and summer
What two simple molecules are used in photosynthesis to make carbohydrates and
what is the energy source for the mild synthetic process. - ANSWER CO2 & water
, Reproductive capability of weeds is enhanced by - ANSWER Their ability to grow over a
wide range of conditions
Primary methods of weed seed dispersal include all of the following methods except -
ANSWER Spread through vegetative propoguels
Tillage affects the weed seed bank by - ANSWER All of the above
Perennial plants - ANSWER Live longer than two years
A biotype of a weed is a - ANSWER Locally adapted variety of a weed that is genetically
distinct from other population
In rice the repeated use of sulfonylurea herbicides has - ANSWER Monitoring for weeds
would will be less expensive
One pattern of weed sampling that can be taken into account field variation is -
ANSWER Stratified sampling
Classical biological control is achieved through - ANSWER Establishment of self
sustaining populations of exotic natural enemies
Which type of organisms is most commonly used for biological controlled weeds -
ANSWER Arthropods
In order to have a classical biological control program which of the following steps
would be needed - ANSWER The project must be approved by the agricultural
department of the county from which the invasion weed originates
