Fundamental Principles of Fundamental Principles of Pest ControlPest Control

Dr. Richard M. HousemanDr. Richard M. Houseman

Department of EntomologyDepartment of EntomologyUniversity of Missouri-ColumbiaUniversity of Missouri-Columbia

ObjectivesObjectives

• Unit 1: pg. 1-39 “Applying Pesticides Correctly”– Pests– Identification and Damage

• Insects• Plant Diseases• Weeds• Vertebrates

– Pest Management– Pesticides

• Mode of Action

Core ManualCore Manual

• ‘Learning Objectives’– Clues to what is

important

• ‘Terms to Know’– Definitions of common

words

• ‘Test Your Knowledge’– Example test questions

Pest Management Pest Management (pg.5)(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 StrategiesManagement 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 StrategiesManagement 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 StrategiesManagement Strategies

• Chemical• The use of natural or

synthetic substances that directly cause the death, repulsion, or attraction of pests.

Considerations• Mode of Action• Persistence• Non-target effects• Resistance

Mode of ActionMode of Action

• Mode of Action– The way a chemical kills a pest.

Examples:• Repellents, poisons, eradicants, systemics

PersistencePersistence

• 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 EffectsNon-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.

ResistanceResistance

• 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

ResistanceResistance

• 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 Pests (pg.3)(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 Pests (pg.3)(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 Pest Identification (pg.3)(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 Insect & Insect-like Pests (pg.6(pg.6))

• Physical Features• Segmented bodies• Jointed appendages• Exoskeleton made of

chitin• Bilateral symmetry

InsectsInsects

• Three body regions (pg.6)

• Head– 1 Pair of antennae– Various mouthparts

• Thorax– 3 pairs of legs– 2 pairs of wings

• Abdomen– Body systems

InsectsInsects

• Life Cycle (pg.7)– Metamorphosis

1. NoneOnly change is size

2. GradualEgg, nymph, adult

3. IncompleteEgg, nymph, adult (H2O)

4. CompleteEgg, larva, pupa, adult

Insect-like Groups Insect-like Groups (pg.8)(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 GroupsInsect-like Groups

• Nematodes– Microscopic roundworms

• Mollusks– Slugs, snails

Look like insect larvae– Non-segmented– No metamorphosis

Insect Pests of PlantsInsect Pests of Plants (pg.10) (pg.10)

• Types of damage– Leaf eating– Plant-sucking– Internal feeding– Stem boring– Root feeding

Pests of AnimalsPests of Animals (pg.11) (pg.11)

• Types of damage– Stinging– Biting– Blood sucking– Toxin injecting

InsecticidesInsecticides (pg.15) (pg.15)

• Modes of Action1. Repellents

Keep insects away from an area or host

2. DisruptersInterfere mechanically with body function

3. PoisonsDeactivate biological systems in the body

– Stomach = must be eaten– Contact = must be touched

Plant PathogensPlant Pathogens (pg.16) (pg.16)

• Plant Disease– Any condition that causes a plant to function or

appear different from normal

Plant Diseases Plant Diseases (pg.16)(pg.16)

• Plant Responses to Disease Agents

1. Overdeveloped tissuesie. galls, leaf curls, swelling

2. Underdeveloped tissuesie. stunting, lack of chlorophyll

3. Death of Tissuesie. leaf spot, wilting, blight, cankers

Plant DiseasesPlant Diseases

• Pathogens include:– Fungi– Bacteria– Viruses– Mycoplasmas

FungiFungi (pg.16) (pg.16)

• Feed on other organisms• Most are beneficial

– Decomposers

• A few parasites– Feed on living plant

tissues

• Reproduce by spores• Microscopic, resistant

stage

FungiFungi

• Symptoms• Soft rot of fruit• Rusts, smuts• Curling, powdery

mildew of leaves • Spots on leaves

BacteriaBacteria (pg.17) (pg.17)

• Microscopic• Symptoms

• Blights, spots , rots

• Reproduce by cell division

VirusesViruses (pg.17) (pg.17)

• Sub-microscopic• Symptoms

• Abnormal growth, mosaics

• Reproduce inside host cell

• Vector transfer

MycoplasmasMycoplasmas (pg.17) (pg.17)

• Smallest living things• Plant-feeders

• Symptoms• Yellow, stunting

• Reproduce independently

• Insects, mites, grafting

Fungicides & BactericidesFungicides & 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

WeedsWeeds (pg.21) (pg.21)

• A weed is any plant growing where it is not wanted.

Effects:– Compete for resources– Contaminate harvest– Harbor pests or release toxins– Look ‘bad’

WeedsWeeds

• Development (pg.21)– Seedling– Vegetative

Producing leaves, stems, roots

– ReproductiveProducing flowers, seeds

– Maturity

WeedsWeeds

• Life Cycles (pg.21)– Annuals = one year– Biennials = two years– Perennials = more that

two years

Weed Identification Weed Identification (pg.22)(pg.22)

• Grasses• Narrow, parallel veins,

round stems

• Sedges• Narrow, parallel veins,

triangular stems

• Broadleaves• Fan-like, branching

veins

Herbicides Herbicides (pg.25)(pg.25)

• Modes of Action– Contact

• kills parts of plant the chemical touches

– Translocated • absorbed and distributed throughout the plant

– Selective • kills only undesireable plants

– Non-selective • kills all plants in an area

or

or

HerbicidesHerbicides

Herbicides Herbicides (pg.26)(pg.26)

• Modes of Action (cont’)– 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

or

VertebratesVertebrates (pg.29) (pg.29)

• Have backbones• Many potential pests

• Various situations and impacts.

• Eat crops, kill livestock, transmit disease, contamination, etc.

Poisons Poisons (pg.30)(pg.30)

• Few pesticides available– Rodenticides: most commonly-used– Piscicides– Avicides

• Usually highly toxic to humans

SummarySummary

• 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.