Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

AGR 549 (Weeds) > Exam 3 > Flashcards

Exam 3 Flashcards

1
Q

What is an example of biological weed control?

A

Using the thistle head weevil to control Musk (Nodding) Thistle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How does the thistle head weevil control musk (nodding) thistle?

A
  • lays its eggs in the head of the thistle

- larvae hatch and feed on the thistle head

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the concern with chemical weed control?

A

Resistance building up in weeds to herbicides.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the “goals” of chemical weed control?

A

1- Permit weed control where tillage isn’t possible.
2- Allow for no-till farming
3- reduce # of tillage operations required
4- reduce amount of labor related to weed control
5- controls weeds that were previously difficult and costly to control
6- allow for more flexibility for crop management

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is an example previous practice that chemical control has allowed us to replace because of its costliness and difficulty?

A

Clean fallowing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are some of the issues with chemical weed control? (5)

A
  • Kills non-target plants (via drift, runoff, etc.)
  • harms animals indirectly ( via algae)
  • Poor public reception
  • perception by some that herbicide can resolve all weed issues
  • problems caused improper selection, storage, handling, and application.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What plant was found to be resistant to 4 classes of herbicide across the state of Missouri?

A

Water Hemp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What herbicides were predominantly used between 1900-1940?

A

Inorganic Herbicides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the example family of herbicides used between 1900-1940?

A

Chlorates

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What herbicides were predominantly used between 1940-1980?

A

Organic Herbicides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What herbicides were predominantly used between 1980-1995?

A

Selective Post-Emergent Herbicides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What herbicides were predominantly used between 1995-Present?

A

Trangenic crops with herbicide tolerance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is an example “family/brand” of the herbicides used between 95-present?

A

Roundup Ready Beans/Corn

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does 2,4-D control? What is significant about this?

A
  • Broadleaf plant species

- Was the 1st to provide complete control of creeping perennial broadleafs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How does 2,4-D control weeds so effectively?

A

It is translocated throughout the plant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the #1 herbicide for weed control in corn?

A

Atrazine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What was significant about Paraquat? How toxic is it?

A
  • allowed for no-till practices to become common
  • 1st non selective kill-all herbicide
  • very toxic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does glyphosate control?

A

-perennial grasses and perennial broadleafs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the max amount of Atrazine app. allowed on soils with 30% residue on surface?

A

2lbs/Ac

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is Karst Terrain?

A

Areas that are underlain by limestone that have been opened up by water flow so that sinkholes, caves, and channels are common topographic features.

21
Q

What are the distance restrictions with Atrazine for these features:

  • wells and sinkholes?
  • streams or rivers?
  • lakes or resiovors?
A
  • 50ft
  • 66ft
  • 200ft`
22
Q

Why were 2,4,5-T and Silvex removed from the US market? What is significant about these herbicides?

A

Because they contained trace amounts of vioxin which is a carinogenic compound.
Were used as agent orange in vietnam.

23
Q

What is an example family of post-emergence herbicides?

A

sulfonylurea herbicides

24
Q

(T/F) The total amount of herbicides applied annually have increased sinced 1982

A

False

25
Q

What are the 4 ways herbicides are named?

A
  • Chemical Name
  • Biological Active Ingredient
  • Common Name
  • Trade Name
26
Q

Example of chem name, active ingredient, common name, and trade name?

A

chem name: N-(phosphonomethyl) glycine
active ingredient: isopropylamine salt
common name: Glyphosate
trade name: Roundup-ultra

27
Q

What are the 2 types of plant responses? Examples of each?

A

selective
ex- atrazine (corn is tolerant, pigweeds are not)
non-selective
ex- glyphosate (kills most plants)

28
Q

What are the 2 types of applications? Example of each.

A

-soil applications
Ex- atrazine
-foliar applications
Ex- Glyphosate

29
Q

What are the 4 classes of length of persistence?
What do they each mean?
What is an example of (r) and (hp)?

A

-no residual: doesn’t hurt other crops
-residual: will kill/injure germinating seedlings for relatively short period of time.
Ex- Scepter (53 days)
-persistent: can harm crops planted in rotation after treated crop is harvested.
-highly persistent: harms crops planted during 2nd season after original crop is harvested.
Ex-Lightning (40 months)

30
Q

What are 3 different coverage methods?

A
  • broadcast
  • banded
  • spot-spraying
31
Q

What are 4 methods of spraying (time-wise)?

A
  • early preplant
  • preplant
  • preemergence
  • postemergence
32
Q

What are the 4 types of post emergence spraying (time wise)?

A
  • early postemergence
  • late postemergence
  • directed postemergence
  • layby application
33
Q

What were the 2 methods of soil applications?

A
  • surface applied

- preplant incorporated

34
Q

What are the 4 ways chems are distributed through plants?

A
  • symplastic translocation (phloem translocation)
  • apoplastic translocation (xylem translocation)
  • contact (no translocation)
  • modes of action (cover later)
35
Q

What are the 3 herbicide families named?

A
  • Sulfonylurea
  • Triazine
  • Other ones
36
Q

What is vapor drift? What herb. has this really been an issue with lately?

A

Herb. hits target, then some of it vaporizes and moves with the wind.
-Dicamba

37
Q

What is the issue that has been causing dicamba problems? Explain it.

A

Air Inversion- warm and cool air flip causing sideway wind

38
Q

Who labels Herbs in US?

A

EPA

39
Q

Can each state select its legal herbs?

A

Yes

40
Q

What is hazard formula?

A

Hazard=toxicity * exposure

41
Q

What is tolerance level?

A

max amount (dosage) of herb. allowed in crop

42
Q

How is toxicity measured?

A

LD50

43
Q

What is LD50?

A

amount of dose required to kill half of test pop.

44
Q

How is LD figured?

A

mg of chemcal/kg of body wt.

45
Q

(T/F)Once EPA approves registration, it is a legal document?

A

True

46
Q

What is FIFRA? What’s it do?

A

Federal Insecticide, Fungicide, and Rodenticide Act

Also requires labelling of herbicides

47
Q

(T/F) If a product is pasture labelled, you can assume it is good for all plants found in pastures ( including clovers)?

A

True

48
Q

Will herbicides be specifically labelled by livestock type such as Horse?

A

No, will only say livestock.

AGR 549 (Weeds) (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions