Chapter 15

Question 1

It is natural for weeds to fill empty niches in cropping systems.

Answer 1

True

Question 2

Weeds can be classified by the environments in which they grow.

Answer 2

True

Question 3

Crop plants are never weeds.

Answer 3

False

Question 4

Biennial weeds flower in the first year.

Answer 4

False

Question 5

Most dicots are easier to kill by cultivation than monocots.

Answer 5

True

Question 6

A weed must be alive in order to demonstrate allelopathic properties.

Answer 6

False

Question 7

Over 95 percent of the corn, soybean, and cotton crops grown are treated with herbicides.

Answer 7

True

Question 8

Weeds can interfere with harvesting equipment.

Answer 8

True

Question 9

Weed seed tends to be bigger than crop seed.

Answer 9

False

Question 10

Animals do not have a significant role in weed dispersal.

Answer 10

False

Question 11

Insecticides are used more than any other pesticide.

Answer 11

False

Question 12

It is a violation of federal law to use an herbicide in a manner inconsistent with its labeling.

Answer 12

True

Question 13

Selective herbicides affect almost all plants.

Answer 13

False

Question 14

Different crop species select for different weed species.

Answer 14

True

Question 15

A disadvantage of biological control is the possibility of affecting non-target species.

Answer 15

True

Question 16

Tillage is an effective strategy of weed control regardless of weed species.

Answer 16

False

Question 17

The main concern with atrazine is leaching and accumulation in surface and groundwater.

Answer 17

True

Question 18

A plant can be classified as a weed if it:

A. causes economic loss to a crop
B. is harmful to humans and livestock
C. is detrimental to wildlife or ecosystems
D. all answers are correct

Answer 18

D. all answers are correct

Question 19

Weeds that are especially injurious are classified by the government as:

A. toxic
B. noxious
C. non-native
D. exotic

Answer 19

B. noxious

Question 20

The long-term persistence of a certain annual weed species is most likely due to:

A. extensive root system
B. herbicide resistance
C. high seed production
D. tolerance to tillage

Answer 20

C. high seed production

Question 21

A weed that reproduces asexually is most likely:

A. an annual
B. a biennial
C. a perennial
D. none of these answers are correct

Answer 21

C. a perennial

Question 22

Milk sickness is caused when people drink milk from cows who have consumed which weed?

A. poisen ivy
B. musk thistle
C. pigweed
D. white snakeroot

Answer 22

D. white snakeroot

Question 23

The first defense against weeds is”

A. prevention of establishment
B. herbicides
C. tillage
D. biocontrols

Answer 23

A. prevention of establishment

Question 24

Which agency of the USDA is responsible for preventing the introduction of noxious weeds?

A. EPA
B. APHIS
C. ARS
D. NRCS

Answer 24

B. APHIS

Question 25

Which agency is responsible for approving new herbicides? A. EPA B. APHIS C. ARS D. NRCS

Answer 25

A. EPA

Question 26

In what year were genetically engineered crops first introduced? A. 1991 B. 1993 C. 1996 D. 1998

Answer 26

C. 1996

Question 27

Which type of ingredients are added to a herbicide formulation to facilitate application and handling or to increase activity? A. active ingredient B. inert ingredient C. chemical ingredient D. restricted ingredient

Answer 27

B. inert ingredient

Question 28

LD50 is a measure of: A. dispersion B. toxicity C. activity D. suspension

Answer 28

B. toxicity

Question 29

The mode of action for glyphosate is: A. growth regulator B. photosynthesis inhibitor C. amino acid synthesis inhibitor D. cell membrane disrupter

Answer 29

C. amino acid synthesis inhibitor

Question 30

The mode of action for 2, 4-D is: A. growth regulator B. photosynthesis inhibitor C. amino acid synthesis inhibitor D. cell membrane disrupter

Answer 30

A. growth regulator

Question 31

The mode of action for atrazine is: A. growth regulator B. photosynthesis inhibitor C. amino acid synthesis inhibitor D. cell membrane disrupter

Answer 31

B. photosynthesis inhibitor

Question 32

Which type of herbicide is applied to foliage? A. preemergence B. preplant C. systemic D. contact

Answer 32

D. contact

Question 33

Which type of herbicide would be most useful on an established perennial weed? A. preemergence B. preplant C. systemic D. contact

Answer 33

C. systemic

Question 34

Which would NOT be an appropriate strategy to prevent herbicide resistance? A. crop rotation B. using extra herbicide C. herbicide rotation D. tillage

Answer 34

B. using extra herbicide

Question 35

Grassy weeds would be easiest to control in which crop? A. corn B. wheat C. soybean D. oats

Answer 35

C. soybean