PCA: Weeds Exam Questions and Answers
Verified 100% Correct | Pass Assured
Weed control: steaming - ANSWER The use of high temperature water onto weeds
Describe some preventative measures that can be used to manage weeds: Quarantine -
ANSWER Hold livestock that may be infested with seed in a single location until they are
shorn or until weed seeds have had the chance to pass through their digestive system.
Feed out infested fodder in a feed lot type situation only and introduce clean fodder to
stock.
Mode of Action - ANSWER The mechanisms by which herbicides kill plants
amides (propanil) - ANSWER MoA- inhibition of their photosynthesis and CO2 fixation
bipyridiliums (paraquat, diquat) - ANSWER MoA- inhibiting photosynthesis
dinitroanilines (trifluralin, pendimethalin); - ANSWER MoA- inhibition of cell mitosis
diphenylethers (oxyfluorfen); - ANSWER MoA- upturing of the cell membrane. Soil and
foliar applied with limited movement in the soil
glycine (glyphosate); - ANSWER MoA- binds to and blocks the activity of the enzyme
enolpyruvylshikimate-3-phosphate synthase
, phenoxy carboxylic acids (auxinic herbicides, 2,4-D); - ANSWER MoA- plant growth
hormone auxin, which results in uncontrolled growth and eventually death. selective
herbicide which kills many terrestrial and aquatic broadleaf weeds
phosphinic acid (glufosinate); - ANSWER MoA- glutamine synthetase inhibitor that binds
to the glutamate site. die due to a buildup of ammonia in the thylakoid lumen
sulfonylureas (chlorsulfuron, rimsulfuron); - ANSWER MoA- direct inhibition of DNA
synthesis.
thiocarbamates (EPTC, thiobencarb); - ANSWER MoA-
triazines (atrazine, simazine); - ANSWER MoA- act as inhibitors of plastoquinone
binding; inhibits Photosystem II
ureas (linuron, diuron). - ANSWER MoA- foliar absorbed and residual herbicide. inhibits
photosynthesis at photosystem II
phytotoxicity; - ANSWER Injury or damage to a sensitive plant caused by a chemical
exposure.
adjuvant; - ANSWER ormulation or added to the spray tank to improve herbicidal
activity or application characteristics.
cross-resistance; - ANSWER Refers to a biotype that is resistant to two or more
chemically similar herbicides
multiple resistance; - ANSWER Refers to weed biotype that is resistant to two or more
chemically unrelated herbicides
Verified 100% Correct | Pass Assured
Weed control: steaming - ANSWER The use of high temperature water onto weeds
Describe some preventative measures that can be used to manage weeds: Quarantine -
ANSWER Hold livestock that may be infested with seed in a single location until they are
shorn or until weed seeds have had the chance to pass through their digestive system.
Feed out infested fodder in a feed lot type situation only and introduce clean fodder to
stock.
Mode of Action - ANSWER The mechanisms by which herbicides kill plants
amides (propanil) - ANSWER MoA- inhibition of their photosynthesis and CO2 fixation
bipyridiliums (paraquat, diquat) - ANSWER MoA- inhibiting photosynthesis
dinitroanilines (trifluralin, pendimethalin); - ANSWER MoA- inhibition of cell mitosis
diphenylethers (oxyfluorfen); - ANSWER MoA- upturing of the cell membrane. Soil and
foliar applied with limited movement in the soil
glycine (glyphosate); - ANSWER MoA- binds to and blocks the activity of the enzyme
enolpyruvylshikimate-3-phosphate synthase
, phenoxy carboxylic acids (auxinic herbicides, 2,4-D); - ANSWER MoA- plant growth
hormone auxin, which results in uncontrolled growth and eventually death. selective
herbicide which kills many terrestrial and aquatic broadleaf weeds
phosphinic acid (glufosinate); - ANSWER MoA- glutamine synthetase inhibitor that binds
to the glutamate site. die due to a buildup of ammonia in the thylakoid lumen
sulfonylureas (chlorsulfuron, rimsulfuron); - ANSWER MoA- direct inhibition of DNA
synthesis.
thiocarbamates (EPTC, thiobencarb); - ANSWER MoA-
triazines (atrazine, simazine); - ANSWER MoA- act as inhibitors of plastoquinone
binding; inhibits Photosystem II
ureas (linuron, diuron). - ANSWER MoA- foliar absorbed and residual herbicide. inhibits
photosynthesis at photosystem II
phytotoxicity; - ANSWER Injury or damage to a sensitive plant caused by a chemical
exposure.
adjuvant; - ANSWER ormulation or added to the spray tank to improve herbicidal
activity or application characteristics.
cross-resistance; - ANSWER Refers to a biotype that is resistant to two or more
chemically similar herbicides
multiple resistance; - ANSWER Refers to weed biotype that is resistant to two or more
chemically unrelated herbicides
