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 allopathic properties
False
Over 95% 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 crops 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 ecosystem
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. Poison 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 Ingredients B. Inert Ingredients C. Chemical Ingredients D. Restricted Ingredients
B. Inert Ingredients
LD50 is a measure of: A. Dispersion B. Toxicity C. Activity D. Suspension
B. Toxicity
The mode of action of 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. Pre Emergence B. Pre Plant C. Systemic D. Contact
D. Contact
Which type of herbicide would be most useful on an established perennial weed? A. Pre Emergence B. Pre Plant 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
Weeds that live on land are classified as ________, whereas those that are a problem in water are _______
Terrestrial and Aquatic
The three life cycles weeds can be classified by are _______, _______ and _______
Annual, Biennial and Perennial
_______ annual weeds are those that germinate in the fall, are vegetative in the winter and flower in the following spring
Perennial
Biennial plants require _______ season to complete their life cycle
Two
Rye infected with Claviceps purpurea forms ________
Ergot
The reservoir of weed seeds in the soil is called the ______
Seed Bank
Weed can develop _______ to herbicides with detoxifying or morphological modifications
Biotypes
The most widely used herbicide is ________
Round Up
On its label, an herbicide has three names, including the _______ name, the _______ name and the _______ name
Common, Trade and Chemical
_______ use pesticides present little danger to humans or the environment, whereas _______ use pesticides are harmful to humans or the environment
General and Ristricted
The types of herbicide application based on timing are _______, ________, ________ and ________
Pre-plant, Pre-Emergent, Post-Emergent and Post-Harvest
Bull Thistle
Biennial
Pigweed
Summer Annual
Jimson Weed
Summer Annual
Bermuda Grass
Perennial
Canada Thistle
Perennial
Velvetleaf
Summer Annual
Leafy Spurge
Perennial
Shepherd’s Purse
Winter Annual
Dandelion
Perennial
Musk Thistle
Biennial
Johnsongrass
Perennial
Chickweed
Winter Annual
Caution
Category III
Warming
Category II
Danger
Category I
Poison
Category I