Entomology For Master

Gardeners

Molly Greenwood

Spring 2017

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

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

Movement and Spread○ Adults have wings & legs

○ Adults can migrate

○ Larvae have legs

○ Larvae can walk

○ Larvae can move with wind

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

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

Characteristics of Insects○ Arthropods: exoskeleton, jointed appendages

○ Adult Insects:

○ Head, thorax, abdomen

○ 1pair antennae

○ 3 pair legs

○ 2 pair of wings Head

Thorax

Abdomen

1. Head:

Sensory Organa) 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

Insect Classification

Insect Classification

Insect Classification

Taxonomic Classification○ Common level: Order and Family

○ Basis for classification

○ Mouthparts

○ Type of wings

○ Type of metamorphosis

• 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

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