Transcript Document

Fundamental Principles of
Pest Control
Dr. Richard M. Houseman
Department of Entomology
University of Missouri-Columbia
Objectives
• Unit 1: pg. 1-39 “Applying Pesticides Correctly”
– Pests
– Identification and Damage
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Insects
Plant Diseases
Weeds
Vertebrates
– Pest Management
– Pesticides
• Mode of Action
Core Manual
• ‘Learning Objectives’
– Clues to what is important
• ‘Terms to Know’
– Definitions of common
words
• ‘Test Your Knowledge’
– Example test questions
Pest Management (pg.5)
Objectives
1. Prevention = keep from
becoming a problem
2. Suppression = reducing
to an acceptable level
3. Eradication = destroying
an entire pest
population
Management Strategies
• Mechanical
• Exclusion/removal
• Heat/cold
• Biological
• Natural enemies,
microbials
• Pheromones/hormones
• Cultural
• Tilling, burning, mowing,
flooding
• Crop rotation, trap crops
• Planting/harvest timing
Management Strategies
• Sanitation
• Eliminate breeding sites
• Remove
pathogens/sources
• Disinfect
equipment/tools
• Host Resistance
• Using disease-resistant
varieties
• Genetics
• Manipulate host
resistance
• Sterility in pest
Management Strategies
• Chemical
• The use of natural or
synthetic substances that
directly cause the death,
repulsion, or attraction of
pests.
Considerations
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Mode of Action
Persistence
Non-target effects
Resistance
Mode of Action
• Mode of Action
– The way a chemical kills a pest.
Examples:
• Repellents, poisons, eradicants, systemics
Persistence
• Persistence
– The length of time a chemical is active after being
applied.
Categories:
• Non-Persistent
– Kills the pest, breaks down in a relatively short period of time
• Persistent
– Residues remain active for period of time after application
Non-Target Effects
• Non-Target Effects
– Pesticide effects on non-pest organisms.
Potential risks:
• May kill beneficial organisms
• May create new pests
– Ex.-Killing natural enemies of a non-pest.
Resistance
• Resistance
– Lessening of the effectiveness of a pesticide for
reducing the pest population
Principles:
• Chemicals kill only susceptible pests
• Survivors pass traits for survival to their offspring
• Resistance develops over generations
Resistance
• To promote:
– Use same pesticide
repeatedly
– Use over large areas
– Use highly residual
chemicals
• To limit:
– Rotate pesticides
– Target applications
– Use persistent chemicals
wisely
Pests (pg.3)
• A Pest is any unwanted organism
– Based on what organism does, not on what they are.
• Compete for food or water
• Cause injury, disease, or annoyance
Pests (pg.3)
Types of Pests
1. Continuous = nearly
always present
2. Sporadic = occasionally
present;
migratory/cyclical
3. Potential = not normally
pests, require control only
in certain situations
Pest Identification (pg.3)
• How to Identify?
• Physical features
• Damage or Symptoms
• Why Identify?
• Pests differ in their habitats, behavior, life cycles, and
susceptibility to control methods.
Insect & Insect-like Pests (pg.6)
• Physical Features
• Segmented bodies
• Jointed appendages
• Exoskeleton made of
chitin
• Bilateral symmetry
Insects
• Three body regions (pg.6)
• Head
– 1 Pair of antennae
– Various mouthparts
• Thorax
– 3 pairs of legs
– 2 pairs of wings
• Abdomen
– Body systems
Insects
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Life Cycle (pg.7)
–
Metamorphosis
1. None
Only change is size
2. Gradual
Egg, nymph, adult
3. Incomplete
Egg, nymph, adult (H2O)
4. Complete
Egg, larva, pupa, adult
Insect-like Groups (pg.8)
• Arachnids
– Spiders, mites, ticks
• 2 regions, 8 legs
• Crustaceans
– Pillbugs
• 3 regions, >8 legs
• Chilopods
– Centipedes
• Many regions & legs
• Diplopods
– Millipedes
• Many regions & legs
Insect-like Groups
• Nematodes
– Microscopic roundworms
• Mollusks
– Slugs, snails
Look like insect larvae
– Non-segmented
– No metamorphosis
Insect Pests of Plants (pg.10)
• Types of damage
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Leaf eating
Plant-sucking
Internal feeding
Stem boring
Root feeding
Pests of Animals (pg.11)
• Types of damage
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Stinging
Biting
Blood sucking
Toxin injecting
Insecticides (pg.15)
• Modes of Action
1. Repellents
Keep insects away from an area or host
2. Disrupters
Interfere mechanically with body function
3. Poisons
Deactivate biological systems in the body
– Stomach = must be eaten
– Contact = must be touched
Plant Pathogens (pg.16)
• Plant Disease
– Any condition that causes a plant to function or
appear different from normal
Plant Diseases (pg.16)
• Plant Responses to Disease Agents
1. Overdeveloped tissues
ie. galls, leaf curls, swelling
2. Underdeveloped tissues
ie. stunting, lack of chlorophyll
3. Death of Tissues
ie. leaf spot, wilting, blight, cankers
Plant Diseases
• Pathogens include:
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Fungi
Bacteria
Viruses
Mycoplasmas
Fungi (pg.16)
• Feed on other organisms
• Most are beneficial
– Decomposers
• A few parasites
– Feed on living plant
tissues
• Reproduce by spores
• Microscopic, resistant
stage
Fungi
• Symptoms
• Soft rot of fruit
• Rusts, smuts
• Curling, powdery mildew
of leaves
• Spots on leaves
Bacteria (pg.17)
• Microscopic
• Symptoms
• Blights, spots , rots
• Reproduce by cell division
Viruses (pg.17)
• Sub-microscopic
• Symptoms
• Abnormal growth,
mosaics
• Reproduce inside host cell
• Vector transfer
Mycoplasmas (pg.17)
• Smallest living things
• Plant-feeders
• Symptoms
• Yellow, stunting
• Reproduce independently
• Insects, mites, grafting
Fungicides & Bactericides
• Modes of Action (pg.20)
– Protectants
• Applied before or during
initial infection
– Eradicants
• Applied after infection
– Systemics
• Internal transport to all
tissues of plant
Weeds (pg.21)
• A weed is any plant growing where it is not
wanted.
Effects:
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Compete for resources
Contaminate harvest
Harbor pests or release toxins
Look ‘bad’
Weeds
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Development (pg.21)
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Seedling
Vegetative
Producing leaves, stems,
roots
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Reproductive
Producing flowers, seeds
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Maturity
Weeds
• Life Cycles (pg.21)
– Annuals = one year
– Biennials = two years
– Perennials = more that
two years
Weed Identification (pg.22)
• Grasses
• Narrow, parallel veins,
round stems
• Sedges
• Narrow, parallel veins,
triangular stems
• Broadleaves
• Fan-like, branching veins
Herbicides (pg.25)
• Modes of Action
or
– Contact
• kills parts of plant the chemical touches
– Translocated
• absorbed and distributed throughout the plant
– Selective
or
• kills only undesireable plants
– Non-selective
• kills all plants in an area
Herbicides
Herbicides (pg.26)
• Modes of Action (cont’)
or
– Foliar
• Applied to leaves of the weed (foliage)
– Soil
• Applied to the ground around the weed
Example:
2,4-D is a foliar-translocated-nonpersistent-selective
Vertebrates (pg.29)
• Have backbones
• Many potential pests
• Various situations and
impacts.
• Eat crops, kill livestock,
transmit disease,
contamination, etc.
Poisons (pg.30)
• Few pesticides available
– Rodenticides: most commonly-used
– Piscicides
– Avicides
• Usually highly toxic to humans
Summary
• Identification of the pest and an understanding of its
biology is important.
• The best pest management programs combine all of the
available control tactics.
• When using chemicals, it is important to understand their
mode of action, persistence, risk of resistance, and their
effect on non-target organisms.