Pests of Landscape Trees

Wizzie Brown

Texas A&M Agrilife Extension

Tips for pest management

• Always identify the insect

– Pest vs. beneficial

Biological Control

• Using other organisms to control a pest

– Conservation

– Augmentation

– Classical or Importation

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Erik Burkness forestryimages.org

Tips for pest management

• Always identify the insect

– Pest vs. beneficial

• Know what is causing the plant problem

Are ANTS really killing your

plant?

Tips for pest management

• Always identify the insect

– Pest vs. beneficial

• Know what is causing the plant problem

• Inspect plants regularly

Differences in Inspection

From a distance- admiring Up close- inspecting

klru

Tips for pest management

• Always identify the insect

– Pest vs. beneficial

• Know what is causing the plant problem

• Inspect plants regularly

• Use practices that help to avoid insect problems

– Sanitation, proper watering, proper fertilization, proper

spacing

Cultural Control

• Modifications to

normal plant care to

reduce or avoid pest

problems

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drlawnenterprise.com

Monrovia

University of Florida

Aggie Horticulture

Mechanical Control

• Use of labor, materials

(not pesticides) &

machinery to reduce

pests plantgardens101.com

Texas A&M University

Diy network www.safesolutionsinc.com

Black & Decker

Physical Control

• Environmental

manipulations that

indirectly control

pests

• Altering light,

humidity, temperature

Leslie Doyle

Tips for pest management

• Always identify the insect

– Pest vs. beneficial

• Know what is causing the plant problem

• Inspect plants regularly

• Use practices that help to avoid insect problems

– Sanitation, proper watering, proper fertilization, proper

spacing

• Conserve beneficial insects

– Make WISE pesticide choices

Using pesticides wisely

• Choose targeted pesticide if possible

• Target treatment area

• Read & follow label instructions

• Texas is a SITE state

Tent Caterpillars

• Description: larvae

various colors;

various markings

(stripes, “keyholes”,

dashes)

– Egg masses on twigs

or bark

– Web in crotch of trees

• Do not feed within

webbing

Tent Caterpillars

• Attacks: various ornamental & fruit trees &

shrubs

• Damage: defoliation; unsightly webs

• Management:

– Prune twigs with egg masses

– Prune out webbing or knock out with a stick

– Tear open webs to allow beneficial insects into

webbing

– High-pressure water sprays

– Pesticides: Bacillus thuringiensis var. kurstaki,

insecticidal soap, spinosad, azadirachtin (neem),

pyrethrins, pyrethroids, carbaryl, acephate

Fall Webworms

• Description: larvae pale

green/yellow with long

tufts of hair

– Egg masses on underside

of leaves

– Webs on branches

• Enlarge web when more

leaves are needed to feed

upon

• 2-4 generations

• Usually show up around

May

Fall Webworms • Attacks: fruit, nut, ornamental trees & shrubs (no

conifers)

• Damage: defoliation; unsightly webs

• Management:

– Destroy leaves with egg masses

– Prune out webbing or knock out with a stick

– Tear open webs to allow beneficial insects into

webbing

– High-pressure water sprays

– Pesticides: Bacillus thuringiensis var. kurstaki,

insecticidal soap, spinosad, azadirachtin (neem),

pyrethrins, pyrethroids, carbaryl, acephate

• Make sure to open web!

Bagworms • Description: create bags

from plant parts and silk;

inside is larvae

• Attacks: broadleaf &

coniferous trees

• Damage: feed on leaves

& creation of bags

• Mgmt: handpicking; apply

sprays after eggs hatch in

spring & larvae are small

– Pesticides: Bt kurstaki,

spinosad, azadirachtin

(neem), pyrethrins,

pyrethroids, carbaryl

Cankerworms

• Description: color variable; striped longitudinally – Two major species: spring

& fall

• Attacks: broadleaf trees

• Damage: defoliation – feed on leaves in April &

May then drop to ground in May & June to pupate

• Mgmt: control early stages • Pesticides: Bt kurstaki, spinosad,

azadirachtin (neem), pyrethrins, pyrethroids, carbaryl

Bark Lice

• Description: small; black;

live in clusters

• Create webbing on tree

trunks

• Damage: none

• Mgmt: none

recommended

– High pressure water to

remove web

• Feed on lichens, molds &

fungi growing on tree-

beneficial!

Borers

• Long-horned/Round-

headed

– Adults with long antennae

– Larvae whitish; elongate;

small head area

– Round to oval tunnels

• Metallic wood-borers/Flat-

headed

– Adults bullet-shaped; short

antennae; metallic colors

– Larvae whitish; elongate;

widened body behind head

– Oval to flattened tunnels

Borers

• Management:

– Keep plants healthy!

• Select species for given area

• Select proper site for planting

• Water & fertilize properly

• Avoid tree damage by mowing, etc.

– Residuals will kill adults laying eggs & larvae hatching

out, not larvae already tunneling in the wood

(acephate, carbaryl, pyrethroids)

– Systemics are usually ineffective for borers,

especially on larger trees

Thrips

• Description: small; single

mandible; fringed wings

– Hide in folded areas of the

plant

• Attacks:

• Damage: silvery streaks;

transmit viruses to plants

• Mgmt: high pressure

water; insecticidal soaps;

horticultural oils;

azadirachtin (neem),

spinosad, permethrin;

pyrethrins

Insect Galls

• Description: abnormal

plant growths caused

by insects, mites,

fungi, nematodes or

bacteria

• Attacks: numerous

plants

• Damage: deformity on

plant

• Mgmt: prevention

Lace Bugs

• Description: small;

flattened; rectangular;

lacey

• Attacks: various

• Damage: spotting on

leaves; discoloration; leaf

drop

• Mgmt: high pressure

water; insecticidal soaps;

horticultural oils;

pyrethrins

Leafminers

• Description: small

flies or wasps

• Attacks: various

• Damage: damage

plant material by

feeding between leaf

layers

• Mgmt: allow natural

enemies to control

population; remove

infested leaves

Aphids

• Small; cornicles

• Yellowing, stunting, curling, honeydew (sooty mold), transmit viruses

• Weed management

• Proper watering & fertilization

• High pressure water spray

• Control ants

• Pruning, removal of infested areas

• Row covers

• Pesticides – Insecticidal soap

– Horticultural oils

– Botanicals

– Synthetic contacts

– Systemics NCSU

Mealybugs & Scale Insects

• Often do not look like insects – Mealybugs are mobile

– Scales mobile in 1st instar

• Yellowing, stunting, curling, honeydew (sooty mold)

• Pruning*

• High pressure water spray

• Pesticides – Insecticidal soap

– Horticultural oils*

– Botanicals

– Synthetic contacts

– Systemics*

* Scale insect control

Whiteflies

• Small, whitish, waxy coating

• Remove sap, reduce plant vigor, secrete honeydew (leads to sooty mold), transmit viruses

• Conserve beneficial organisms

• Maximize distance between host crops

• Sanitation

• Weed management

• Reflective mulches

• Pruning, removal of infested leaves

• Traps

• Control ants

• High pressure water spray

• Pesticides

North Carolina Cooperative Extension

Hoppers

• Various colors & shapes

• Yellowing, stunting, curling, honeydew (sooty mold), transmit viruses

• Weed management

• Proper watering & fertilization

• High pressure water spray

• Row covers

• Pesticides – Insecticidal soap

– Horticultural oils

– Botanicals

– Synthetic contacts

– Systemics

Tom Bentley

Stink bugs/ leaf-footed bugs

• Shield-shaped; triangle on

back, variable color

• Brownish-black, expanded

region on hind leg

• Yellowing, curling, stunting

• Conserve beneficial organisms

• Vacuuming

• Row cover

• Pesticides

K-State

Grasshoppers

• Description: nymphs look

similar to adults

• Attacks: crops, gardens,

trees & shrubs

• Damage: defoliation

• Mgmt: chickens; cover

prized plants with

screening; Nosema

locustae; botanicals,

spinosad, pyrethroids,

carbaryl

Texas Leaf-Cutting Ants

• Description: size varies; three pairs of spines on thorax & one pair on head

• Nest marked by several crater-shaped mounds 5-14 inches high surrounding an entrance hole – Interior has various

chambers (some 15-20 feet deep)

– Underground foraging tunnels can be 500 feet long

• Above ground will travel over 600 feet for suitable plants

Texas Leaf-Cutting Ants

• Attacks: grasses, many fruit, nut & ornamental trees & shrubs – Will attack pine trees in winter when other plants are

not available

• Damage: cut pieces off plant to take to nest for fungus gardens

• Management: – Difficult...can be up to 2 million ants per colony!

– Bait for around mound areas

– Temporarily protect with contact insecticides

Spider Mites

• Description: green; two

dark spots

• Attacks: vegetable crops

• Damage: color loss;

green to yellow to reddish

• Mgmt: natural enemies

(predatory mites,

ladybugs, minute pirate

bugs); oils; soap; – Treat underside of leaves!

Wizzie Brown

512-854-9600

ebrown@ag.tamu.edu

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