PCA: Weeds Exam Study Guide3+Questions and
Answers Verified 100% Correct
amides (propanil) - ANSWER MoA- inhibition of their photosynthesis and CO2 fixation
bipyridiliums (paraquat, diquat) - ANSWER MoA- Electron acceptors - PSI ( accepts
electrons to form toxic free radicals)
dinitroanilines (trifluralin, pendimethalin); - ANSWER MoA- inhibition of cell mitosis
diphenylethers (oxyfluorfen); - ANSWER MoA- desctruction 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- Energy production inhibitors.
Inhibits lipid synthesis and cell division.
, 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 Formulation 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
plantback restrictions. - ANSWER some pesticides can adversely affect the growth of
sensitive rotational crops or because a tolerance for the active ingredient has not been
established for the next crop in rotation.
Describe soil conditions that: increase the persistence or availability of most soil-applied
herbicides. - ANSWER Are held tightly in soils that have high clay content or high levels
or OM. Results- have to increase herbicide usage.
pH - ANSWER pH affects the herbicides ability to be absorbed.
Answers Verified 100% Correct
amides (propanil) - ANSWER MoA- inhibition of their photosynthesis and CO2 fixation
bipyridiliums (paraquat, diquat) - ANSWER MoA- Electron acceptors - PSI ( accepts
electrons to form toxic free radicals)
dinitroanilines (trifluralin, pendimethalin); - ANSWER MoA- inhibition of cell mitosis
diphenylethers (oxyfluorfen); - ANSWER MoA- desctruction 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- Energy production inhibitors.
Inhibits lipid synthesis and cell division.
, 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 Formulation 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
plantback restrictions. - ANSWER some pesticides can adversely affect the growth of
sensitive rotational crops or because a tolerance for the active ingredient has not been
established for the next crop in rotation.
Describe soil conditions that: increase the persistence or availability of most soil-applied
herbicides. - ANSWER Are held tightly in soils that have high clay content or high levels
or OM. Results- have to increase herbicide usage.
pH - ANSWER pH affects the herbicides ability to be absorbed.
