Agron 317 Test 4

The ALS enzyme is involved in the synthesis of

amino acids

Group 15 herbicides are applied

both of the above

There are no know weeds that have evolved resistance to group 4 herbicides

false

A farmer is concerned with the slow growth and development of his corn crop, and suspects herbicides might be playing a role....

group 3

Group 4 herbicides mimic the activity of

indole acetic acids (IAA)

The mode of action of the dinitroaniline herbicides is:

inhibiting polymerization of tubulin

Which best describes the mode of action of group 27 herbicides?

inhibition of carotene synthesis results in chlorophyll destruction and bleaching of leave

The mode of action of paraquat is:

inhibition of electron transfer in photosystem l

The mode of action of the triazine herbicides is:

inhibition of electron transfer in photosystem ll

The mode of action of triazine herbicides is:

inhibition of electron transfer in photosystem ll

The mode of action of glufosinate is:

inhibition of photosynthesis via disrupting incorporation of ammonia into glutamine

The mode of action of glyphosate is:

inhibition of the shikimate acid pathway

A primary risk with the deregulations of the new growth regulator resistant crops is:

injury to non-target plants from herbicide drift or contamination of groundwater

What happens to the half-life of atrazine as the soil pH increases:

it increases

You visit a soybean field where Farmer A suspects his soybean crop....

lactofen (PPO inhibitor)

The purpose of AMS commonly added to the spray tank when using glyphosate is to:

limit tie-up of glyphosate

Group 1 herbicides inhibit:

lipid synthesis

The symptoms of glyphosate are highly variable depending....Which of the following would NOT be expected following glyphosate drift on sensitive corn?

necrotic lesions developing rapidly on leaves contacted by the spray

Injury Symptoms of postemergence applications of HG 14 includes:

necrotic lesions where spray droplets contact foilage

Dinitroaniline herbicides are used for:

preemergence and postemergence control of germinating weeds or both

The major use of group 27 herbicides is best described as

preemergence and postemergence herbicides used in corn

Group 15 herbicides are used

preemergence to control germinating weeds

Which of the following best describes how group 5 herbicides kill plants?

production of reactive oxygen species disrupts cellular membranes

Which factor does not contribute to the high level of effectiveness of glyphosate?

rapid absorption into the plant

At label rates glufosinate does not have soil activity due to:

rapid degradation by soil microbes

Glyphosate is a

systemic, postemergence herbicide

Glufosinate is a

systemic, preemergence herbicide??

The Enlist herbicide trait in corn provides resistance to both 2-4-D, and fop herbicides (ACC-ase inhibitor) because:

the herbicide molecules have a similar structual arrangement that the transgenic enzyme can metabolize

The primary advantage of resolved isomer formulations (e.g. s-metolachlor, Dual ll Magnum) is that:

the risk of selecting resistance is reduced

At label rates glyphosate does NOT have soil activity due to:

tight binding by soil colloids

At label rates, paraquat does not have soil activity due to:

tight binding to soil colloids

Which of the following herbicide groups is only used for non-selective, postemergence weed control?

22

A high Kd results in this herbicide family providing less consistent weed control in dry soils than other preemergence herbicides.

Acetamides

Which herbicide has been detected most frequently in Iowa surface waters?

Atrazine

The primary injury symptom of the Group 27 herbicides is:

Bleaching of foliage

The ACC-ase inhibiting herbicides are ineffective on broadleaves becasue:

Broadleaves have an insensitive form of ACC-ase enzymes

The HPPD enzyme is involved in the synthesis of

Carotenes

The PPO enzyme is involved in the synthesis of

Chlorophyll

Symptoms of sublethal doses of glufosinate are best described as

Chlorosis and necrosis of foilage contacted by the spray

The site of action for glyphosate is:

EPSPS

An advantage of group 2 herbicides is that all of the products are short lived in the soil and thus a user doesn't need to worry about rotational crop sensitivity.

False

Which herbicide family started the chemical era of weed management?

Growth Regulator

ACCase

HG 1

Which herbicide group is used primarily postemergence to control grasses in broadleaf crops?

HG 1

PPO

HG 14

Which of the following herbicide groups includes contact postemergence herbicides:

HG 14

Which of the following herbicide groups is registered for postemergence applications in soybean and consistently cauess necrosis to emerged leaves when applied postemergence?

HG 14

Improper unfurling of leaves on corn seedlings is a characteristic of which herbicide group?

HG 15

ALS

HG 2

Which herbicide group has the most herbicide resistant species worldwide:

HG 2

Which of the following herbicides has the most herbicide resistant species worldwise:

HG 2

HPPD

HG 27

Which herbicide family is used primarily postemegence to control broadleaves in grass crops?

HG 4

Photosystem ll

HG 5

Which herbicide group is used to control weeds preemergence and postemergence?

HG 5

Acetamide

HG15

Bottlebrush roots on corn seedlings is a common symptom of:

HG2

Sulfonylurea

HG2

Weeds may escape control by preemergence herbicides if rainfall fails to move the herbicides...Which herbicides group

HG3 or 15

Phenoxy

HG4

Triazine

HG5

Glyphosate

HG9

Any herbicides can drift from target sit....

HPPD inhibitor

The mode of action of Group 15 herbicides is:

Inhibition of very long chain fatty acids

Which herbicide is most toxic to humans and other animals?

Paraquat

The distinct injury symptom of the ACC-ase inhibitors is:

Rotting of growing points

What condition occasionally causes girding of the soybean hypocotyl with preemergence of group 14 herbicides?

The first rain after herbicide application occurs when soybeans are just emerging through the soil surface

Which best describes how most herbicides disrupt plant processes?

The herbicide binds to the target site, therefore preventing it from functioning

All herbicides that interfere with photosynthesis disrupt the light reactions rather than dark reactions.

True

Group 1 herbicides are phloem mobile

True

Injury symptoms of the group 4 herbicides include:

abnormal leaf veination, epinastry