entomology for master gardeners mike wagner regents professor-emeritus northern arizona university...

Entomology For Master Gardeners

Mike WagnerRegents Professor-

EmeritusNorthern Arizona

UniversitySchool 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 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

Characteristics of Insects Arthropods: exoskeleton, jointed

appendages Adult Insects:

Head, thorax, abdomen 1pair antennae 3 pair legs 2 pair of wings

1. Head: Sensory Organ

a) Paired appendages (antennae)b) Mouthparts

2. Thorax: Locomotion

3. Abdomen: Reproductive and

Digestive

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

Thorax

Abdomen

• Prolegs

• Thoracic legs

Prolegs

Thoracic legs

Insect Relatives Spiders, mites, ticks, centipedes,

millipedes, sowbugs, snails, slugs Bugs vs. “bugs”

Insect Growth and Development Metamorphosis Shed exoskeleton (molting) Stages

Egg Larva/nymph Pupa Adult

Instars

Metamorphosis: Simple

Wing pads

• Wings

Squash bug

Metamorphosis: Complete

Metamorphosis

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

Insect Feeding/Mouthparts Chewing

Hard mandibles Holes, tunnels, partial eaten leaves

Sucking Straw (stylet), probosis Curling, stunting, mottling, galls Phytotoxic necrosis

4 Types of Mouth Parts

Piercing/sucking

Straw

Mouth Parts

Chewing

Piercing/sopping

Insect Classification

Insect Classification

Insect Classification

Taxonomic Classification Common level: Order and Family Basis for classification

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

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

Complete Chewing

Dermaptera: earwigs

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

Gradual Chewing

Diptera: flies, mosquitoes

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

Complete Larvae: chewing/hooksAdult: sponging, piercing

Hemiptera: true bugs

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

Gradual Piercing, sucking

Homoptera: aphids, leaf hoppers, white flies, scales

Attributes: small soft bodied insects, unwinged forms, attack many vegetables, multiple generations, parthenogenesis, some disease vectors (CTV), greenhouse pests

Gradual Sucking

Hymenoptera: bees, wasps, ants, sawflies

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

Complete Chewing

Isoptera: termites

Attributes: soft bodied insects, winged or wingless, colonies occur in ground or in wood, drywood and subterranean termites, caste system, social

Gradual Chewing

Lepidoptera: moths, butterflies

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

Complete Larvae: chewing Adults: sucking

Neuroptera: lacewings, antlions

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

Complete Chewing

Orthoptera: grasshoppers, crickets, mantids, cockroaches

Attributes: hard bodied adult, two pair of wings, front wings are hard, adults and nymphs cause damage, moderate pests

Gradual Chewing

Siphonaptera: fleas

Attributes: wingless insects, live as ectoparasites on birds and mammals, body is laterally flattened, often jumping, important disease vectors, include plague and typhus

Complete Sucking

Thysanoptera: thrips

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

Gradual Sucking

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:

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

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 all approaches to manage pest 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

Conventional resistant varieties GMO’s

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

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!