Basic Entomology

Master Gardener Training

Dan Nortman

Extension Agent, ANR-Horticulture

York/ Poquoson

What is an insect?

Exoskeleton

• Regulates water

• Provides structure

• Waxy coating acts in a protective manner

• Represents evolution

Six Legs

Usually specialized for the

insect’s lifestyle

Wings

Size

.17 mm

Antennae

How insects taste the world around them and communicate with each other

Taxonomy

• Kingdom: Animalia

• Phylum: Arthropoda

• Class: Insecta

• Order: ~32 (Coleoptera)

• Family: >700

(Curculionidae)

• Genus

• Species

Specific epithet:

Conotrachelus nenuphar

How many? 1-10million

Plum Curculio

Arthropods

• Hard shell

(exoskeleton)

• Body

segmentation

• Jointed legs

Non-insect Arthropods

• Crustacea

• Arachnida

• Symphyla

Non-insect Arthropods

• Chilopoda

• Diplopoda

Non-insect Arthropods

• Crustaceans- Isopods- 5pr. Legs

• Arachnids- spiders, ets.- 4 pr. Legs

• Symphyla- Small, many legs, translucent

• Chilopoda- “one-leg” (one leg per

segment)- flat in x-section

• Diplopoda- “two-leg” (double legs per

segment)- round in x-section

Arachnids- Spiders

• Predatory

• Venemous- rarely

enough to kill or do

serious harm

• Two body segments

• Beneficial generalist

predators

– Inefficient

Arachnids- Opiliones

• Harvestmen, daddy

longlegs

• Detritivores

• No venom

• One body segment

(fused abdomen and

cephalothorax)

Arachnids- Ticks

• Two body segments,

though hard to tell

• Very common human

and animal pests

• Lyme disease

– Only Black legged

(deer) tick

Dog Tick

Deer Tick

Lone Star Tick

Arachnids- Mites

• Many niches

• Some serious plant

pests

• Eight legs, one body

segment

• European red mite

• Two spotted spider

mite

Spruce mite on arborvitae

Spruce mite on Fraser fir

Spruce spider mite

• Overwinter as eggs

• Egg hatch begins at 20 C

• Optimum 26 C, 50-60% RH

• 10 generations annually

• High mortality at higher temperatures

Checking for Spider Mites

• Monitor

– Hot sites

• Check for mites

– Tap test

• Treat

– At peak of activity

• Avoid

– Planting in hot sites

Southern red mite

Two-spotted spider mite

Oak mite damage

Chilopoda

• Centipedes

• Predators

• No dangerous

species in VA

• Some tropical species

are dangerous

• Common: house

centipede

Diplopoda

• Millipedes- 2 legs per

segment

• Feed on decaying

plant material

• Not really a pest

• Overwintering

irritation

Exoskeleton

• Regulates water

• Provides structure

• Waxy coating acts in a protective manner

• Represents evolution

Six Legs

Usually specialized for the

insect’s lifestyle

Wings

Antennae

How insects taste the world around them and communicate with each other

Life Cycle Three ways

No metamorphosis

Incomplete/ Gradual

metamorphosis

Complete

metamorphosis

Why are insects important?

• Biodiversity

• Indicators of pollution

• Medical/ Human health

• Urban pests

• Animal health and happiness

• Crop production

– Pollination

– Integrated Pest Management

Insect identification

• Why is it important?

Thrips: General Pests: • Thrips are common pests of

beans and many other crops

including greenhouses.

• yellow spotting

• feed in buds

• distorted pods and fruit

• insecticidal soap, etc.

• common in dry years

• will bite

Thysanoptera

Hemiptera and Homoptera Mouthparts

“Homoptera”: Aphids

• Piercing mouthparts

• Honeydew

• Reduce vigor

• Many different

species and hosts

• Tended by ants

Aphids

note “tail pipes” life stages

distortion of birch leaf

Aphids

• Monitor for distorted

foliage

• Monitor for

honeydew, sooty

mold

• Monitor for natural

enemies

• Apply insecticidal

soaps

• Apply synthetic

insecticides

Homoptera: Scale insects Sedentary, Piercing mouthparts, hatchlings are the

only mobile stage (“crawlers”)

• Armored scales

– Small (1/8th

inch)

– Shield

– Crawlers

– Dormant oil

• Soft Scales

– Larger (1/4 inch)

– Hemispherical

– Crawlers

– Dormant oil

Scale Life Stages

Soft scale: Cottony maple scale

Cottony maple scale

Soft scale: Wax scale

adult scales infested boxwood

Homoptera, Soft scale:

Oak lecanium scale

scale with crawlers

infested branch

parasitic wasp

Homoptera: Armored scales

gloomy scale obscure scale

tea scale

parasitic

wasp

Euonymus

scale

Armored Scales – Oystershell Scale Lepidosaphes ulmi

Armored Scales – San Jose Quadraspidiotus perniciosus

Scale control, generally

• Monitor for sooty mold

• Monitor for natural enemies

• Apply horticultural oils in winter

• Avoid pesticides when predators are active

Scale Control

• Euonymous scale- May 10-20 July 5-15

• Lecanium scale- June 15-20

• Oak Kermes- June 10-15

• Oystershell Scale- May 5-20, July 20-25

• White Peach Scale- May 1-10; July 5-15;

and September 1-10

Hemiptera: Piercing

mouthparts,

hemielytra type wings

• Examples: Stink Bugs and Leaffooted bugs

• General Pests

• Common late summer feeders on fruits and pods

• white halos

• reduce weeds

Pantatomidae: Stink bug

Harlequin bug

http://insects.tamu.edu/images/insects/color/harleq2.jpg

Hemiptera:

Harlequin bug • Harlequin bugs are

common on kale,

mustard, and other

crucifers (cole crops)

including weeds.

• Type of stink bug

• yellow spots

• OW as adults

• clean plow in fall, remove

weeds.

Harlequin bug, adult

Hemiptera:

Squash bug • Squash bug is common in

spring and late summer

• all cucurbits

• row covers in spring

• Proper fertilization

• Removal and destruction

of crop debris after

harvest

• egg masses can be hand-

picked

• trap with boards, squash

bugs in AM

http://www.uidaho.edu/so-

id/entomology/Home_&_Garden/squash%20

bug.jpg

Squash bug, Hemiptera, Coreidae

Hemiptera: Azalea lace bug

life stages

damage to azalea

Azalea Lace Bug

• Monitor

– Overwintering population

– Adult emergence

• Selective spraying (sunny areas)

• Follow-up monitoring

Dermaptera

• Earwigs

• Very short front wings, with complex folding of hind wings

• Pincers

• Not a serious pest, but will thrive in groundcover

• Can damage mature fruits

• Trapping them in upturned flower pot with newspaper

Coleoptera

• Beetles

• Front wings hard or

leathery- elytra

• Larva are grublike,

generally

• About 25% of all life

• 350,000 described, 3-

8 million estimated

Coleoptera: Beetles. Chewing mouthparts

Coleoptera

• Scarabaeidae

• Buprestidae

• Cerambycidae

• Curculionidae

• Coccinellidae

• Meloidae

• Chrysomelidae

Scarabaeidae

• Scarab beetles

• Lamellate antennae

• Leaf feeders, some decomposers

• Common landscape and garden pests: – Japanese beetle

– Rose chafer

– Lawn grubs

– June beetles

Japanese beetle

• Very wide host range

• Foliar devastation-

Rosaceae

• Lawn trouble

• Lawn insecticides-

targeting grubs

• Milky spore- works

selectively

• Exclusion- Hand

pollination may be

required

• Shake into a soapy

bucket

Japanese beetles

adults feeding on leaf

Japanese Beetle

Buprestidae

• Flat headed borers

• Flat in profile

• Often very metallic

and pretty

• Most bore into dead,

dying trees

• Some attack healthy

trees

– Apple tree borer

– Emerald ash borer

Emerald Ash Borer (EAB)

In the wake of

Chestnut blight

& Hemlock

Wooly Adelgid

is EAB

Virginia’s next

tree/forest

disaster?

• Killed more than 40 million ash trees in southeastern

Michigan alone, with tens of millions more lost in OH, IL, IN, PA,

WV, MO, WI and VA.

• Cost municipalities, property owners, nursery operators and forest

products industries tens of millions of dollars.

Emerald Ash Borer: What to Look for

D-shaped emergence holes

Epicormic branching

Galleries Branch dieback

Cerambycidae

• Long horned beetles – Have very long

antennae

• Also wood borers

• Round in x-section

• Many minor pests that can become serious – Oak borer

– Locust borer

– Twig girdler

Cerambycidae

Roundheaded

Borers

Adults are called

longhorned beetles,

larvae are called

roundheaded borers

Twig Girdler

• Chews a ring on a twig to feed and lay an egg

• Twig dies, larvae develops in dead part

• Twig falls off of tree

• Many hosts – Pecan, hickory, oak

• Collect and burn fallen twigs

Borers • Look

– Early color change

– Dead branches

– Loose bark

– Sawdust

• Remove – Infested trees

– debark

• Treat – Neighboring trees of same species

• Secondary pests – Attracted to dead and dying trees

Curculionidae

• Two groups

– Weevils

– Bark beetles

• Weevils have snout,

bark beetles don’t

• Weevils feed on plant

material

• Bark beetles are

pests in wood

Weevils

• Wide variety of hosts

• Some common pests – Boll weevil

– Plum curculio

• Common in stored grains

• Botanical insecticides

• Not usually a problem for the home gardener

Bark Beetles

• Small, brownish

beetles

• Some eat wood

• Others eat fungus

that they “farm”

• Systemic

insecticides are

best

Damage comparison

Bark Beetle Buprestid

Coccinellidae

• Ladybird beetles

• Most are predator

– Extremely valuable

– Aphids, scales,

whiteflies, etc.

• One pest- Mexican

bean beetle

Mexican Bean Beetle

• Can be devastating in

large numbers

• Attacks most legumes

• Promoting biocontrol

is the best option, but

several insecticides

are available

• Planting early can

also help

Meloidae

• Blister beetles

• Spanish Fly

• Leathery elytra

• “Fleshy” bodies

• Occasional pests

• Botanical insecticides

are effective, most

general use

insecticides

Colorado Potato Beetle

• Orange and black

stripes on elytra

• Very, very destructive

• Prone to resistance

• The bane and funding

source of many, many

entomologists

• Handpick

• Bt, Neem

Neuroptera

• Lacewings

• “Little gator” larvae

• Adults feed on nectar

Lepidoptera: What is a

Caterpillar?

2-5

Eastern tent caterpillar

larva

eggs

tent

Eastern tent caterpillar: pest of wild

cherry and some fruit trees • Trees will put out leaves again

• Prune egg masses Nov.-Mar.

• Remove small tents manually

• Apply insecticides to tents

• Migrating last instar larvae cannot be controlled

• Recreational caterpillar burning: DO NOT torch tents

Gypsy moth

mature larva

laying eggs

defoliated forest

Gypsy moth -

treatments

pheromone traps

trapping with burlap bands

Fall Webworm

• Highly

Polyphagous

• Loves Pecan

• Damage

unsightly, but

usually negligible

larva

Lepidoptera: Bagworms

Bagworm

• Monitor degree of infestation

• Handpick overwintering bags

• Monitor egg hatch beginning in May

• Apply microbial insecticides

• Apply synthetic insecticides

http://www.hort.uconn.edu/ipm/veg/pics/icw2.jpg

Imported cabbageworm:

Lepidoptera

Squash Vine borer

• Squash vine borer

found on most

cucurbits

• Lepidoptera

• 2 generations/year

• row covers

• cut out worms

• dirt every 4-6 feet

• insecticides ASAP

after seeing damage

http://www.oznet.ksu.edu/

dp_hfrr/HortImage/Squash

%20Vine%20Borer%20La

rva.gif

Tomato

Hornworm

• Tomato hornworms are

late summer defoliators

• hand-pick, keep

parasitized worms

• Tobacco hornworm,

Manduca sexta

• Tomato hornworm,

Manduca

quinquemaculata

Tomato hornworm parasites

Photo form Stuart Sutphin

Sesiidae

• Clearwing moths

• Borers

• Common tree fruit

borers

– Peachtree borer

– Plum borer

– Dogwood borer

Sesiidae

• Look

– Damage esp. at graft

sites

– Trap for moths if you

suspect a problem

• Treat

– Flying moths that have

not laid eggs (timing)

– Treat at sites when

moths reach

thresholds

Hymenoptera

• Bees, wasps, sawflies

• Important beneficials

– Pollinators

– Parasitoid wasps

• Major pest: sawflies

Parasitoid wasps

• Braconidae

• Ichneumonidae

• Trichogrammatidae

Sawflies

• Pests of evergreens

and other plants

• Caterpillar like larvae

• 6+ pairs of prolegs

Diptera

• Flies

• Two wings

• Few common garden pests

– Seed corn maggot

– Fruit flies

• Several important beneficial

– Syrphid fly

– Cecidomyiids

– Tachinids

Syrphid Fly

• Larvae are excellent

predators

• Adults are nectar

feeders

– Bee mimics

Cecidomyiid larvae

• Small larvae, excellent predators

• Predatory Midge

Tachinids

Dan Nortman

Virginia Cooperative Extension

Extension, Agriculture and Natural

Resources, Horticulture

100 County Drive, Yorktown, VA

757-898-4940

dnortman@vt.edu