Insect Pest Management

• Insects

–1.5 - 30 million species

–Most Insects are not pests

“For 150 million years, insects have served as the sexual handmaidens to the flowering plants. Most plants on earth cannot reproduce without them. When the bugs fly from flower to flower for the nectar, some of the pollen is transferred from stigma to stigma. Wham bam, thank you, ma’am.”

-Rowan Jacobsen, Fruitless Fall

Classification

• Kingdom > Animal

• Phylum > Arthropoda (one of 33 Phyla)

• Class > e.g. Insecta, Arachnida

• Order > e.g. Coleoptera, Diptera

• Family

• Genus

• Species 1.5 – 30 million

ARTHROPODS

• Legs with joints

• Segmented Bodies

• Members of that Group – Insects

– Crustaceans

– Mites

– Ticks

– Spiders

– Millipedes

– Centipedes

– Symphylans

CLASS INSECTA (HEXAPODA)

• Adults have 6 legs

• 3 body segments,

– Head, thorax and abdomen

• One pair of antennae

• Some have wings

• Spineless = invertebrate

• Exoskeleton

MOST IMPORTANT

FEATURES OF INSECT

PESTS

• MOUTHPARTS:

– Piercing/sucking

– Chewing

– Sponging

– Siphoning

arthursclipart.org

Mouthparts: Chewing Beetles (Coleoptera) Caterpillars (Lepidoptera) Grasshoppers (Orthoptera) Termites (Isoptera)

Mouthparts: Rasping –Sucking (e.g

Thrips)

Piercing- Sucking (e.g. Mosquito)

Sponging Mouthparts

(e.g. Housefly)

Siphoning

Chewing – Lapping (e.g. Honey Bee)

METAMORPHOSIS

• INSECTS CHANGE FORM AS THEY DEVELOP

• FOUR TYPES OF METAMORPHOSIS

– None

– Complete

– Incomplete

– Gradual

Egg Juvenile Adult

No Metamorphosis

• Body size & proportions change

• Some times segments may be added;

• No wings

• Same habitat

–

Egg Larvae Pupa Adult

Complete Metamorphosis

• Immatures rarely resemble adults

• Wing development begins internally

• Different habitats

Southwest Corn Borer

Egg Naiads Adult

Incomplete Metamorphosis

• Immatures may or may not resemble adults

• Immatures in water

• No pupal stage

• Different habitats

Egg Nymphs Adult

Gradual metamorphosis

• Similar in appearance • Wing pads in later immature

stages • Same habitats

Gradual metamorphosis similar to simple, except most of these

insects will develop wings.

OTHER ARTHROPODS

• ARACHNIDS

– Spiders, mites, ticks

SPIDERS

• USUALLY CONSIDERED BENEFICIAL

• Few poisonous

• Eat other insects

(beneficials, too)

• GENERAL FEEDERS

MITES

• FOLIAGE FEEDERS

– Spider mites, spruce mites

• BUD FEEDERS

– Cyclamen mites, Eriophyoid mites – only mites known to transmit viruses (gall mites)

• BULB MITES

• PREDATOR MITES

Eriophyid mites

Predator mites

Many mites are predator mites – feed on

pest mites. Commercially available and good biological control agents!

CRUSTACEANS

• Sow bugs, pill bugs

– Same class as crabs, lobster

CENTIPEDES

• Predators that feed on insects and spiders

• One pair of legs per segment

• 15 or more pairs of legs

MILLIPEDES

• FEED ON DECAYING PLANT MATTER AND SOMETIMES PLANT ROOTS

• 2 PAIRS OF LEGS PER SEGMENT

• 30 OR MORE PAIRS OF LEGS

SYMPHYLANS

• SOIL DWELLING PESTS

• FEED ON GERMINATING SEEDS, ROOTS AND BULBS

• WHITE WITH NUMEROUS LEGS AND PROMINENT ANTENNAE

• Adults = 12 pairs of legs

• Biology and Control:

• http://insects.ippc.orst.edu/pnw/insects?30IPMW02.dat

BENEFICIAL ARTHROPODS

• Products – Silk, dyes

• Food source

• Improved soil structure

• Scavengers

• Predators and parasites of other pests

BENEFICIALS • PREDATORS

– Directly catch and feed on prey

• PARASITES

– Use other insects to incubate eggs and feed larvae

INSECT PESTS

• INSECTS CAUSE DAMAGE TO PLANTS IN MANY WAYS

– Fruit and seed destruction

– Tissue damage and vigor reduction

– Disease transmission

– Aesthetics

– Public nuisance (honeydew)

How to tell if you have a pest

• SYMPTOMS

– What the host shows or exhibits

• Tissue damage

• Root damage

• Distortion

• Discoloration

• Dieback

Boll weevil, kidsbrittanica.com

How to tell if you have a pest

• SIGNS - What the pest leaves for you to find

• Frass: debris the insect leaves, shed skin from molting, feces, webbing

• Pest or eggs, froth, honeydew, sawdust

Amateur Entomologists’ Society amentsoc.org

Grubs

Grubs (Order: Coleoptera)

• Weevil larva

• Larva feed on roots – Adults also feed on foliage and seed

• Adult mouthparts are curved into a downward curving snout – Characteristic semi-circular notching on

the leaves

• Serious pests of ornamental plants

Grubs

Other Root Feeders

• Crane fly larva - Order: Diptera

• Wireworms - Order: Coleoptera

• Fungus gnat larva - Order: Diptera

Fungus Gnat

Wood Borers (Order: Coleoptera)

• Larva have well developed chewing mouthparts and can reach great size

• Larva bore into woody trunks and twigs – Branches can be girdled and dieback

• Eggs laid in wounds of woody plants

Wood Borers

Leaf Miners

• Can be moth, beetle or fly larva

• Orders: Lepidoptera, Coleoptera, Diptera

• Cause damage on ornamental evergreens

• Damage to edible leafy crops and flowers

Vegetable Leaf Miner

Birch Leaf Miner

Bark Beetles (Order: Coleoptera)

• Cause leaf damage, tunnel under bark

• Serious vectors of fungal diseases

– Example: Dutch Elm Disease

Bark Beetle

Bark Beetle

Sucking Insects (Order: Homoptera)

• Example: Aphids, Leafhoppers and Scale

• Piercing-sucking mouthparts

• Feeding damage, causing distortion and weakening plants

• Can spread plant viruses

Aphids

Aphids

Aphids

Rasping-sucking pests (Order: Thrysanoptera)

• Thrips

– Directly damage plants by cuticle destruction and feeding damage

– Vectors of plant viruses

Rasping-sucking pests (Order: Acarina)

• Spider mites

– Feeding damage

– Eriophyid mites, vector diseases (viruses)

Gall forming insects

• Spruce Adelgids

– Homoptera

• Honey locust pod gall midge

– Diptera

• Bladder gall mites on Maple

– Acarina

• Oak leaf galls, wasp

– Hymenoptera

Gall forming insects

Gall forming insects

Tent Caterpillars - Order: Lepidoptera

• Leaf skeletonizers

• Leaf rollers

Caterpillars

Twig Girdlers (Order: Coleoptera)

• Borers, weevils,

– Cause dieback of twigs, shoots

Leaf damaging insects

• Many orders, adults and larva

• Chewing, reduce foliage

• Sucking and rasping damage

• Reduce plant vigor

• Ruin aesthetics

• Can lead to disease infections

• Entomology for Master Gardeners

• http://pest.ca.uky.edu/EXT/master_gardener/entbasics/mouthparts/mouthparts.shtml