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Weed Science > Final Study Guide > Flashcards

Final Study Guide Flashcards

0
Q

Invasive species

A

Non native or alien to the ecosystem or a species whose introduction causes economic, environmental, or human health problems

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1
Q

Define weed

A

ANy undesirable plant in an environment that is competitive with desirable plants or has no function.

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2
Q

3 ways seeds are dispersed,

A

Wind, water, animals

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3
Q

Define ecology

A

The study of organisms in their environment.

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4
Q

What is a perfect flower?

A

A flower with all reproductive parts.

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5
Q

What does WSSA Stand for?

A

Weed science society of America.

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6
Q

Dioecious

A

A plant species that has pistillate and staminate flowers on different plants

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7
Q

Leaf arrangement in which there are two leaves per node.

A

Opposite

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8
Q

Rhizomes

A

Horizontal underground stems

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9
Q

A group of organisms within the same species that occur in a given time and space.

A

Population

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10
Q

Glabrous

A

Leaf that is smooth

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11
Q

Horizontal above ground stems

A

Stolons

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12
Q

Dehiscent

A

Term for type of dry fruit, in which the fruit splits open at maturity

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13
Q

A community plus it’s non living environment

A

Ecosystem

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14
Q

Leaf arrangement with 3 or more leaves per node

A

Whorled

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15
Q

A flower with stamens but no pistil

A

Staminate

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16
Q

Anther and filament make this structure

A

Stamen

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17
Q

Niche

A

An organisms place in its environment

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18
Q

Aggregate

A

A fruit that develops from several ovaries within one flower.

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19
Q

An orderly change in species resulting from modification of the physical environment by the plant community

A

Succession

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20
Q

Monocots have how many:
Cotyledons in seed?
Number of flower parts?
Leaf venation?

A

One
3s
Parallel

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21
Q

Dicots have how many:
Cotyledons per seed?
# of flower parts?
Leaf venation?

A

Two
4s or 5s
Branched

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22
Q

Reasons herbicides are the main method of controlling weeds,

A

They are cheaper
More reliable
Higher return on investment

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23
Q

Induced dormancy

A

Type of dormancy in which unfavorable conditions cause sees to go dormant.

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24
Q

r group

A

Plants that are short lived and produce lots of seed.

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25
Q

The K group

A

Longer lived less seeds

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26
Q

Obligate weeds

A

Weeds that have never been found in the wild stage and that grow only in association with man.

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27
Q

A plant that completes its life cycle in one year

A

Annual

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28
Q

Negative effects of weeds

A 
Reduced yields
Increased costs
Hard to remove 
Harbor other crop pests
Interfere with harvests 
Extra cleaning and processing
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29
Q

Ideal characteristics of weeds

A 
Quickly reproducing
Competitive
Tolerant of stressful conditions
Hard to get rid of
Produces lots of seeds 
Quickly germinating
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30
Q

What are the goals of herbicide application?

A

To kill or suppress the grown of plants

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31
Q

Define formulation

A

Preparation supplied by manufacturing for use,

Manufacturing process carried out by the formulator in preparing a chemical for packaging,

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32
Q

Dry formulation types

A

Water soluble powders and water dispensable granules

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33
Q

Liquid formulation types

A

Water soluble liquids and water dispersal liquids

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34
Q

Dry formulation for direct application

A

Granules and pellets

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35
Q

What carries can be used for herbicide applicators

A

Water or other liquids

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36
Q

Adjuvant define

A

Any substance in herbicide formulation or added to spray tank to modify herbicidal activity

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37
Q

What does a Wetting agent do?

A

Enables spray deposit to spread and make better contact with plant surface

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38
Q

What are the 5 types of adjuvants

A 
Surfactants 
Crop oil concentrate
Comparability agents
Anti foaming agents
Drift control agents
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39
Q

What is the range for ground applications?

A

10 - 20 GPA

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40
Q

What is the range for Air spraying

A

3- 10 GPA

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41
Q

why do different nozzle sizes matter

A

Poor control
Crop injury
Wasted chemical

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42
Q

How should herbicides be stored

A

In a locked temperature controlled area with chemical resistant container treys

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43
Q

How do you dispose of herbicides

A

Triple rinse, drain, and puncture

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44
Q

What are the 3 types of herbicide names

A

Common, chemical, trade name

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45
Q

What’s the difference in selective herbicides and non selective

A

Selective are more toxic to some plants than others

Non selective toxic to all plants

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46
Q

Short residual herbicides

A

Injure or kill in short periods and used in rotated crops

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47
Q

Long residual herbicides

A

Soil sterilants, herbicides used in non-crop perennial crops.

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48
Q

Non-residual herbicides

A

No soil activity noticeable, burn down herbicides and selective post herbicides.

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49
Q

Use to kill crops before planting

A

Preplant burndown

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50
Q

Herbicide rolled into the soil before planting

A

Preplant incorporated

51
Q

Application of herbicide at time of planting or before crop emergence

A

Preemergence

52
Q

After crop or weed emergence

A

Post emergence

53
Q

Difference between systemic and contact herbicides?

A

Systemic translocation to phloem

Contact -no movement plant tissue damaged after exposure

54
Q

Symplastic transport site in plant

A

Phloem affects photosynthesis

55
Q

Apoplastic transport location

A

Xylem moves up only

56
Q

What types of properties or characteristics are used to group herbicides into families

A

Physical/ chemical, biological, environmental fate and impact, toxicological hazards.

57
Q

Measure of the amount of compound that is harmful or lethal when exposed by ingestion, inhalation, or dermal exposure.

A

Toxicity

58
Q

Probability of encountering a harmful dose of a compound.

A

Exposure

59
Q

What does oncogenicity mean?

A

Tumor producing

60
Q

The six Carcinogenicity

A

Six cancer potential categories

61
Q

Birth deformities

A

Tetratogenicity

62
Q

Genetic abnormality

A

Mutagenicity

63
Q

What is the difference between acute and chronic toxicity?

A

Acute is harm after short exposure and chronic is repeat exposure.

64
Q

What is mode of action?

A

The plant process affected by the herbicide.

65
Q

What is mechanism of action?

A

The biochemical site within a plant each herbicide directly interacts with.

66
Q

3 herbicide classification systems

A

WSSA , AUstrailian, Herbicide resistance action committee

67
Q

Lipid synthesis inhibitors are in what group?

A

WSSA 1 and blocks production of phospholipids

68
Q

Amino acid synthesis inhibitors group?

A

WSSA 2 reduction of cell division

69
Q

Nitrogen metabolism inhibitors group?

A

WSSA 10 increase in ammonia.

70
Q

Growth regulators group

A

WSSA 4 clogs xylem and phloem

71
Q

Mitosis inhibitors group

A

WSSA 15 microtubules inhibitors

72
Q

What does LD 50 mean

A

Dose of a substance lethal to 50% of organisms

73
Q

What does LC50 stand for?

A

Concentration of a substance lethal to 50% of organisms

74
Q

What are the five types of toxicological studies that must be done on herbicides?

A

Acute, subacute, chronic feeding and oncogenicity, fish and aquatic organisms, birds

75
Q

How long does it take to develop and register a new herbicide?

A

10-12 years

76
Q

Difference between general use pesticide and restricted use?

A

General use - no reasonable adverse effects on environment and safe to apply
Restricted use- sold only to trained and certified applicators.

77
Q

Section 18 allows for?

A

Emergency situation application

78
Q

IR -4 allows for

A

Research project anoung state exp stations

79
Q

DANGER

A

Highly toxic

80
Q

Warning

A

Moderately toxic

81
Q

caution

A

Slightly toxic

82
Q

Preventative measures when spraying?

A

Long sleeves and pants, gloves, shoes and socks , eyewear.

83
Q

What is included on a herbicide label?

A

Mixing instructions, spraying instructions, calibration, application directions.

84
Q

What informating needed when identifying problems with herbicide?

A

Locate crop injury, access crop condition, determine if label was followed , record all important information.

85
Q

What factors other than herbicide application can cause a problem?

A

Application at wrong stage of growth

86
Q

What is carrying capacity

A

The plant density that can be maintained in a given community over time.

87
Q

What 5 morphological factors of weeds are important?

A 
High germination rate 
Early extensive root system
Large expansive foliage 
Multiple shoots
Climbing growth
88
Q

What is the LAI? Leaf area index?

A

Amount of photosynthetic material or leaf suspended per unit of area of land.

89
Q

When does a weed become competitive in LAI?

A

At 1.0

90
Q

How do weeds reach the LAI ?

A

Through size density,

91
Q

The interaction among species involving both competition and allelopathy,

A

Interference

92
Q

The inhibition of one plant by another through release of toxins,

A

Allelopathy

93
Q

The mutually adverse effects of plants which are competing for a resource in short supply.

A

Competition

94
Q

Interference of plants of the same species.

A

Intraspecific interference

95
Q

Interference of plants of a different species

A

Interspecific interference

96
Q

What weed factors are important?

A 
Species cultivar,
 planting date,
 planting rate,
 duration,
Growth rate growth habit
Allelopathy
97
Q

What crop factors are important?

A 
Species cultivar 
Planting date
Planting rate
Duration
Growth rate
Allelopathy
98
Q

Other factors that influence interference?

A 
Weather
Soil type
Soil fertility 
Tillage
Herbicides and pests
99
Q

Sigmoid relationship chart axis
Y:
X:

A

Y: crop yield
X: weed density

100
Q

What does a longer critical period mean?

A

The crop is less competitive

101
Q

How can weeds still have an effect of there is no yield loss from competition?

A

It can still produce seeds

102
Q

6 general method of control

A 
Preventative and regulatory
Mechanical 
Cultural
Biological
Herbicide 
Biotechnical
103
Q

What is preventative control?

A

The prevention of introduction, establishment, and spread of specific weeds.

104
Q

Farm management practices can be taken to reduce weeds in weed sanitation?

A

Plant weed free seed, clean equipment, screen irrigation water, inspection, pay special attention

105
Q

What regulations are in place for weed seed in seeds?

A

There are noxious laws that prevent noxious weed seed in planting sees or nursery stock.

106
Q

What are noxious weeds?

A

Weeds that cannot be sold and are limited by number / lbs

107
Q

Isolates or prevents the spread of?

A

Quarantine

108
Q

Elimination of weed species?

A

Eradication

109
Q

Implies a reduction in an infestation level?

A

Control

110
Q

What are the mechanical methods of weed control?

A

Tillage, hand picking, mowing, smothering or mulching.

111
Q

Advantages and disadvantages of mechanical control

A

Adv: selective, effective, alternative to herbs, stimulates germination, destroys.
Dis: time consuming, tedious, expensive,

112
Q

Primary tillage is how deep?

Secondary tillage?

A

P: 6- 36
Sec: less than 6

113
Q

Disadvantages of mechanical tillage

A

Soil erosion, energy requirements, increases weed, damages crops, buries weed seed.

114
Q

Use of clear plastic film to cover soil for disease and insect control

A

Solarization

115
Q

3 areas hand weeding is still used?

A

Homeowners,
High priced horticulture
Organic farmers

116
Q

What weed can survive flooding?

A

Johnsongrass

117
Q

What types of management practices improve crop competitiveness?

A

Optimum planting date
Seeding rate
Fertility and irrigation
Cultivar selection

118
Q

What is biological weed control?

A

Using natural methods to fight weeds,

Ex. Bugs

119
Q

Why are biological controls usually aimed at perennial weeds?

A

2/3s of them are perennial!

120
Q

Types of biological control? 3

A

Classical- natural predators
Mycroherbicidal- fungal spores
Feeding- animals

121
Q

What are the 8 contributions of herbicides?

A 
Cost effective
Permit control 
Reduce tillage
Reduce human effort
Controls difficult weeds economically 
Flexible management system
Can solve most weed problems
122
Q

Major risks of using herbicides?

A

Drift injury
Persistent in soil residues
Inconsistent weed control
Resistant weeds

123
Q

What is integrated weed management?

A

The integration of environmentally safe sociologically acceptable control tactics, that reduce weed interference below the economic injury level

124
Q

What are benefits of integrated weed management?

A 
Wholesome food
Increased outputs
Economic stability
Increased biodiversity 
Increased productivity

Weed Science (3 decks)

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