Entomology For Master Gardeners

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Entomology For Master Gardeners

• Mike Wagner
• Regents Professor-Emeritus
• Northern Arizona University
• School of Forestry

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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

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Extent and Economic Importance

• Major form of higher life
• Attack all stages of all species
• Damage equals harvest
• Beneficial aspects

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Beneficial Aspects

• 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

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Characteristics of Insects

• Arthropods exoskeleton, jointed appendages
• Adult Insects
• Head, thorax, abdomen
• 1pair antennae
• 3 pair legs
• 2 pair of wings

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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

• Head
• Sensory Organ
• a) Paired appendages (antennae)
• b) Mouthparts
• 2. Thorax
• Locomotion
• Abdomen
• Reproductive and Digestive

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• Thoracic legs

• Prolegs

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Thoracic legs
Prolegs
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Insect Relatives

• Spiders, mites, ticks, centipedes, millipedes,
  sowbugs, snails, slugs
• Bugs vs. bugs

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Insect Growth and Development

• Metamorphosis
• Shed exoskeleton (molting)
• Stages
• Egg
• Larva/nymph
• Pupa
• Adult
• Instars

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Metamorphosis Simple
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• Wing pads

• Wings

Squash bug
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Metamorphosis Complete
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• Metamorphosis

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Insect Growth and Development

• Gradual
• Egg-nymph-adult
• Nymph similar to adult
• Ex. Aphids, scales, grasshoppers
• Complete
• Egg-larva-pupa-adult
• Larva does damage
• Stages occur in different habitats
• Ex. Beetles, butterflies, flies

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Insect Feeding/Mouthparts

• Chewing
• Hard mandibles
• Holes, tunnels, partial eaten leaves
• Sucking
• Straw (stylet), probosis
• Curling, stunting, mottling, galls
• Phytotoxic necrosis

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• 4 Types of Mouth Parts

Piercing/sucking
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Straw
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Chewing

• Mouth Parts

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Piercing/ sopping
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Insect Classification

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

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Insect Classification
Animal Arthropods Insecta Coleoptera Scolytidae De
ndroctonus brevicomis

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

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Insect Classification

• Kingdom
• Phylum
• Class
• Order
• Family
• Genus
• Species

Animal Arthropods Insecta Coleoptera Scolytidae De
ndroctonus brevicomis
keen pretty clothes out fill guys some
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Taxonomic Classification

• Common level Order and Family
• Basis for classification
• Mouthparts
• Type of wings
• Type of metamorphosis

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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

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Coleoptera beetles, weevils
Complete
Chewing

• Attributes 400,000 species, hard front wings,
  beneficial and pest species, adults and larvae
  may feed on same host

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Dermaptera earwigs
Gradual
Chewing

• Attributes front wings thickened, pest or
  beneficial (aphid predator), nocturnal, hide
  during the day

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Diptera flies, mosquitoes
Larvae chewing/hooks Adult sponging, piercing
Complete

• Attributes larvae legless, adults soft bodied,
  compound eye, one pair of wings, haltere, disease
  vectors, pest and beneficial

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Hemiptera true bugs
Gradual
Piercing, sucking

• Attributes nymphs resemble adults, many plant
  feeding pests, triangle on back, some predators,
  some disease vectors (Chagas disease)

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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

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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

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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

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Lepidoptera moths, butterflies
Larvae chewing Adults sucking
Complete

• Attributes caterpillars, adults have two pairs
  of scaled wings, many defoliators, adults feed on
  nectar, adults pollinate, basis for ecotourism

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Neuroptera lacewings, antlions
Complete
Chewing

• Attributes adults have 2 pairs of membranous
  wings, wings held rooflike, many species are
  predators

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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

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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

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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

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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

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Movement and Spread

• Adults have wings legs
• Adults can migrate
• Larvae have legs
• Larvae can walk
• Larvae can move with wind

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Population Dynamics

• Insects have high reproductive potential
• Can migrate move with plants
• Population limited by
• Environmental resistance
• Host plant resistance
• if you build it, they will come
• Exotic (non-native) insects

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Concept of a Pest

• Interfere with objectives
• Insects play vital ecological roles
• 1 of insects are pests
• Learn to live with damage- economic threshold

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Diagnosing Insect Pest Problems

• Recognize limitations
• Most sick plants are abiotic
• Identify the plant
• Note the symptoms
• Look for broad patterns
• Within plant (leaf vs. fruit)
• Across plant (spot vs. all plants)
• Collect specimens

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Diagnosing Insect Pest Problems Continued

• Take notes
• Formulate hypothesis
• Important? Seek professional advice

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Pest Managment

• Integrated Pest Management
• Legislative Control
• Physical/Mechanical Control
• Cultural Control
• Biological Control
• Chemical Control

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IPM

• Integrate all approaches to manage pest
• Pest ID
• Detection, monitoring models
• Know insect biology
• Ecologically sound

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Legislative Control

• Quarantine
• State regulation- noxious weeds
• Public education critical

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Physical Control

• Insect removal/habitat destruction
• Sanitation/salvage
• Firewood in direct sun
• Physical barriers- cutworms
• Mass trapping
• Trap trees

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Cultural Control

• Crop rotation
• Green manure fallow
• Genetic resistance
• Conventional resistant varieties
• GMOs

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Biological Control

• Ecologically best strategy
• Life history knowledge critical
• Classical vs. Bio. insect pest suppression
• Bio control agents
• Vertebrate predators
• Invertebrate predators
• Invertebrate parasites
• Pathogenic microorganisms
• Ex. Virus, bacteria (Bt), fungi, nematodes

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Chemical Control

• Limitations ecological, cost, hazard
• Follow label-legal document
• Pay attention to pre-harvest interval
• Federal regulation of residual tolerance
• Pesticide applicator certification

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Summary

• Insects are part of natural system
• Provide lots of useful functions
• Apply the least effort to reduce economic
  threshold
• Share the planet!