Chapter 15 Flashcards
It is natural for weeds to fill empty niches in cropping systems.
True
Weeds can be classified by the environments in which they grow.
True
Crop plants are never weeds.
False
Biennial weeds flower in the first year.
False
Most dicots are easier to kill by cultivation than monocots.
True
A weed must be alive in order to demonstrate allelopathic properties.
False
Over 95 percent of the corn, soybean, and cotton crops grown are treated with herbicides.
True
Weeds can interfere with harvesting equipment.
True
Weed seed tends to be bigger than crop seed.
False
Animals do not have a significant role in weed dispersal.
False
Insecticides are used more than any other pesticide.
False
It is a violation of federal law to use an herbicide in a manner inconsistent with its labeling.
True
Selective herbicides affect almost all plants.
False
Different crop species select for different weed species.
True
A disadvantage of biological control is the possibility of affecting non-target species.
True
Tillage is an effective strategy of weed control regardless of weed species.
False
The main concern with atrazine is leaching and accumulation in surface and groundwater.
True
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
D. all answers are correct
Weeds that are especially injurious are classified by the government as:
A. toxic
B. noxious
C. non-native
D. exotic
B. noxious
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
C. high seed production
A weed that reproduces asexually is most likely:
A. an annual
B. a biennial
C. a perennial
D. none of these answers are correct
C. a perennial
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
D. white snakeroot
The first defense against weeds is”
A. prevention of establishment
B. herbicides
C. tillage
D. biocontrols
A. prevention of establishment
Which agency of the USDA is responsible for preventing the introduction of noxious weeds?
A. EPA
B. APHIS
C. ARS
D. NRCS
B. APHIS
Which agency is responsible for approving new herbicides?
A. EPA
B. APHIS
C. ARS
D. NRCS
A. EPA
In what year were genetically engineered crops first introduced?
A. 1991
B. 1993
C. 1996
D. 1998
C. 1996
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
B. inert ingredient
LD50 is a measure of:
A. dispersion
B. toxicity
C. activity
D. suspension
B. toxicity
The mode of action for glyphosate is:
A. growth regulator
B. photosynthesis inhibitor
C. amino acid synthesis inhibitor
D. cell membrane disrupter
C. amino acid synthesis inhibitor
The mode of action for 2, 4-D is:
A. growth regulator
B. photosynthesis inhibitor
C. amino acid synthesis inhibitor
D. cell membrane disrupter
A. growth regulator
The mode of action for atrazine is:
A. growth regulator
B. photosynthesis inhibitor
C. amino acid synthesis inhibitor
D. cell membrane disrupter
B. photosynthesis inhibitor
Which type of herbicide is applied to foliage?
A. preemergence
B. preplant
C. systemic
D. contact
D. contact
Which type of herbicide would be most useful on an established perennial weed?
A. preemergence
B. preplant
C. systemic
D. contact
C. systemic
Which would NOT be an appropriate strategy to prevent herbicide resistance?
A. crop rotation
B. using extra herbicide
C. herbicide rotation
D. tillage
B. using extra herbicide
Grassy weeds would be easiest to control in which crop?
A. corn
B. wheat
C. soybean
D. oats
C. soybean
