Entomology For
Master
Gardeners
Mike Wagner
Regents Professor-Emeritus
Northern Arizona University
School of Forestry
Outline of Topics
 Extent
and Economic Importance
 Insect Growth and Development
 Insect Feeding / Mouthparts
 Classification and Taxonomy
 Movement and Spread
 Population Dynamics / Concept of Pest
 Diagnosing Insect Problems
 Pest Management Approaches
Extent and Economic
Importance
 Major
form of higher life
 Attack all stages of all species
 Damage equals harvest
 Beneficial aspects
Beneficial Aspects
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Pollination
Predators / Parasites
Human food
Biological control agents
Nutrient recycling
Insect products: honey, wax, shellac, dye
Conservation biology
Art and literature
Ecotourism- butterfly farms / exhibits
Characteristicsof Insects
 Arthropods:
exoskeleton, jointed
appendages
 Adult Insects:
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Head, thorax, abdomen
1pair antennae
3 pair legs
2 pair of wings
Arthropods
(Phylum Arthropoda: also include trilobites, horseshoe crabs, spiders,
crustaceans, millipedes, centipedes)
Insects are all in the HEXAPODA (class)
Body with three distinct regions: head, thorax, and abdomen
1. Head:
Sensory Organ
a) Paired appendages
(antennae)
b) Mouthparts
Head
2. Thorax:
Locomotion
3. Abdomen:
Reproductive and
Digestive
Thorax
Abdomen
• Thoracic legs
• Prolegs
Thoracic legs
Prolegs
Insect Relatives
 Spiders,
mites, ticks, centipedes,
millipedes, sowbugs, snails, slugs
 Bugs vs. “bugs”
Insect Growth and
Development
 Metamorphosis
 Shed
exoskeleton (molting)
 Stages
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Egg
Larva/nymph
Pupa
Adult
 Instars
Metamorphosis: Simple
Wing
pads
• Wings
Squash
Metamorphosis: Complete
Metamorphosis
Insect Growth and
Development
 Gradual:
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Egg-nymph-adult
Nymph similar to adult
Ex. Aphids, scales, grasshoppers
 Complete:
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Egg-larva-pupa-adult
Larva does damage
Stages occur in different habitats
Ex. Beetles, butterflies, flies
Insect Feeding/Mouthparts
 Chewing
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Hard mandibles
Holes, tunnels, partial eaten leaves
 Sucking
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Straw (stylet), probosis
Curling, stunting, mottling, galls
Phytotoxic necrosis
4
Types of
Mouth Parts
Piercing/sucking
Straw
Chewing
Mouth
Parts
Piercing/
sopping
Insect Classification
Kingdom
Phylum
Class
Order
Family
Genus
Species
Insect Classification
Animal
Kingdom
Arthropods
Phylum
Insecta
Class
Coleoptera
Order
Family
Genus
Species
Scolytidae
Dendroctonus
brevicomis
Insect Classification
Kingdom
Animal
Phylum
keen
Arthropods
Class
pretty
Insecta
Order
clothes
Coleoptera
Family
Genus
Species
Scolytidae
Dendroctonus
brevicomis
out
fill
guys
some
Taxonomic Classification
 Common
level: Order and Family
 Basis for classification
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Mouthparts
Type of wings
Type of metamorphosis
Common Insect Orders
 Coleoptera:
beetles, weevils
 Dermaptera: earwigs
 Diptera: flies, mosquitoes, gnats, midges
 Hemiptera: true bugs
 Homoptera: aphids, scales, leafhoppers,
cicadas, whiteflies, mealy bugs
 Hymenoptera: bees, wasps, ants, sawflies
 Isoptera: termites
Coleoptera: beetles, weevils
Complete
Chewing
Attributes: 400,000 species, hard front wings, beneficial and
pest species, adults and larvae may feed on same host
Dermaptera: earwigs
Gradual
Chewing
Attributes: front wings thickened, pest or beneficial (aphid
predator), nocturnal, hide during the day
Diptera: flies, mosquitoes
Complete
Larvae: chewing/hooks
Adult: sponging, piercing
Attributes: larvae legless, adults soft bodied, compound
eye, one pair of wings, haltere, disease vectors, pest
and beneficial
Hemiptera: true bugs
Gradual
Piercing, sucking
Attributes: nymphs resemble adults, many plant feeding
pests, triangle on back, some predators, some disease
vectors (Chagas disease)
Homoptera: aphids, leaf
hoppers, white flies, scales
Gradual
Sucking
Attributes: small soft bodied insects, unwinged forms, attack
many vegetables, multiple generations, parthenogenesis,
some disease vectors (CTV), greenhouse pests
Hymenoptera: bees, wasps,
ants, sawflies
Complete
Chewing
Attributes: legless larvae, adult stinger, two pair of
membranous wings, ants with narrow waist, many
species, pollinators, parasites, predators, sawflies are
important defoliators, many species social
Isoptera: termites
Gradual
Chewing
Attributes: soft bodied insects, winged or wingless, colonies
occur in ground or in wood, drywood and subterranean
termites, caste system, social
Lepidoptera: moths, butterflies
Complete
Larvae: chewing
Adults: sucking
Attributes: caterpillars, adults have two pairs of scaled
wings, many defoliators, adults feed on nectar, adults
pollinate, basis for ecotourism
Neuroptera: lacewings, antlions
Complete
Chewing
Attributes: adults have 2 pairs of membranous wings, wings
held rooflike, many species are predators
Orthoptera: grasshoppers,
crickets, mantids, cockroaches
Gradual
Chewing
Attributes: hard bodied adult, two pair of wings,
front wings are hard, adults and nymphs cause
damage, moderate pests
Siphonaptera: fleas
Complete
Sucking
Attributes: wingless insects, live as ectoparasites on birds
and mammals, body is laterally flattened, often jumping,
important disease vectors, include plague and typhus
Thysanoptera: thrips
Gradual
Sucking
Attributes: adults are minute soft bodied, two pairs of long
wings, many feed on plants and especially flowers, cause
cosmetic damage to fruit, some disease transmission
Common Insect Orders
Continued
 Lepidoptera:
moths, butterflies
 Neuroptera: lacewings, antlions
 Odonata: dragonflies, damselflies
 Orthoptera: grasshoppers, crickets,
mantids, cockroaches
 Siphonaptera: fleas
 Thysanoptera: thrips
 Thysanura: siverfish, firebrats
Movement and Spread
 Adults
have wings & legs
 Adults can migrate
 Larvae have legs
 Larvae can walk
 Larvae can move with wind
Population Dynamics
 Insects
have high reproductive potential
 Can migrate; move with plants
 Population limited by:
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Environmental resistance
Host plant resistance
 “if
you build it, they will come”
 Exotic (non-native) insects
Concept of a Pest
 Interfere
with objectives
 Insects play vital ecological roles
 1% of insects are pests
 Learn to live with damage- economic
threshold
Diagnosing Insect Pest
Problems
 Recognize
limitations
 Most “sick” plants are abiotic
 Identify the plant
 Note the symptoms
 Look for broad patterns
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Within plant (leaf vs. fruit)
Across plant (spot vs. all plants)
 Collect
specimens
Diagnosing Insect Pest
Problems Continued
 Take
notes
 Formulate hypothesis
 Important? Seek professional advice
Pest Managment
 Integrated
Pest Management
 Legislative Control
 Physical/Mechanical Control
 Cultural Control
 Biological Control
 Chemical Control
IPM
 Integrate
 Pest
all approaches to manage pest
ID
 Detection, monitoring models
 Know insect biology
 Ecologically sound
Legislative Control
 Quarantine
 State
regulation- noxious weeds
 Public education critical
Physical Control
 Insect
removal/habitat destruction
 Sanitation/salvage
 Firewood in direct sun
 Physical barriers- cutworms
 Mass trapping
 Trap trees
Cultural Control
 Crop
rotation
 Green manure fallow
 Genetic resistance
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Conventional resistant varieties
GMO’s
Biological Control
 Ecologically
best strategy
 Life history knowledge critical
 Classical vs. Bio. insect pest suppression
 Bio control agents
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Vertebrate predators
Invertebrate predators
Invertebrate parasites
Pathogenic microorganisms
 Ex.
Virus, bacteria (Bt), fungi, nematodes
Chemical Control
 Limitations:
ecological, cost, hazard
 Follow label-legal document
 Pay attention to pre-harvest interval
 Federal regulation of residual tolerance
 Pesticide applicator certification
Summary
 Insects
are part of natural system
 Provide lots of useful functions
 Apply the least effort to reduce economic
threshold
 Share the planet!