------------------------- U of MN Extension ServiceM1162
2003


Insecticide Suggestions to Manage Landscape Tree and Shrub Insects


Vera Krischik
Associate Professor
Department of Entomology

Jeffrey D. Hahn
Extension Educator, Entomology
Department of Entomology


©  2003  Regents of the University of Minnesota. All rights reserved.

Table of Contents
How to Use This Publication  

Pest Charts:

Aphids: Leaf Sucking

Aphids: Leaf-Curling
viburnum leaf curl aphid
honeysuckle witches' broom aphid

Aphids: Woolly
alder woolly aphid
apple woolly aphid

Adelgid: Woolly
hemlock woolly adelgid*
pine bark adelgid

Scolyid Borers: Bark Beetles
ambrosia beetle
European elm bark beetle
native elm bark beetle
pine bark beetle

Sesiid Borers: Clearwing
lilac/ash borer
banded ash borer
viburnum borer

Buprestid Borers: Flat Headed
bronze birch borer
emerald ash borer*
flat headed apple tree borer
twolined chestnut borer

Cerambycid Borers: Round Headed
Asian longhorn beetle*
elm borer
locust borer
whitespotted sawyer

Caterpillars: Leaf Chewing
cankerworm
eastern tent caterpillar
fall webworm
forest tent caterpillar
red humped caterpillar
spiny elm caterpillar
spruce budworm
walnut caterpillar
white marked tussock moth
yellow necked caterpillar

Caterpillars: Stem Borers
European pine shoot moth
Zimmerman pine moth

Caterpillars: Leaf Chewing Casebearers
bagworm*
elm case bearer
larch case bearer

Galls Adelgid
Cooley spruce gall
Eastern spruce gall

Cynipid Galls
cynipid wasp oak gall
oak bullet gall
oak rolly polly gall
jumping oak gall
mossy rose gall
spiny rose gall

Galls Psyllid
hackberry nipple gall
hackberry blister gall

Erineum/Bladder/Spindle Galls made by Eriophyid Mites
ash flower gall mite
maple spindle gall
maple bladder gall

Galls made by Flies
tephrytid stem galls
ceccdomyiid stem galls

Leaf Beetle: Adults and Larvae Leaf Chewing
elm leaf beetle
cottonwood leaf beetle
ninebark leaf beetle
viburnum leaf beetle*
willow leaf beetle

Scarab Beetle: Adult Leaf Chewing, Grubs in Soil
Japanese beetle
May/June/Phyllophaga beetle

Leaf Miners
birch leafminer
elm leafminer

Leafhopper: Leaf Sucking
potato leafhopper

Lace Bugs: Leaf Sucking
azalea lace bug*
hawthorne lace bug
oak lace bug

Plant Bugs: Leaf Sucking
ash plant bug
fourlined plant bug
honeylocust plant bug

Sawflies: Leaf Chewing
dogwood sawfly
dusky birch sawfly
European pine sawfly
introduced pine sawfly
larch sawfly
mountain ash sawfly
redheaded pine sawfly
roseslug sawfly
yellowheaded spruce sawfly

Scales: Leaf Sucking
black pineleaf scale(armored scale)
cottony maple scale (soft scale)
European elm scale (soft scale)
lecanium scale (soft scale)
oystershell scale (armored scale)
pine needle scale (armored scale)
pine tortoise scale (soft scale)
scurfy scale (armored scale)
spruce bud scale (soft scale)

Stem Borers
maple petiole borer

Spider Mites: Leaf Sucking
spruce spider mite
twospotted spider mite

Twig Pruners/Twig Girdler

Weevils: Stem Feeding
white pine weevil

Weevils: Root Feeding
black vine weevil
strawberry root weevil

Weevils: Trunk Feeding
Pales weevil
Northern root collar weevil

 

*Not established in Minnesota as of 2003

 

Insecticide Names

For More Information

 

How To Use This Publication

This publication provides information on timing insecticides and insecticide choices. However, it is the responsibility of the applicator to determine the appropriateness, correct timing, and safety requirements of a chemical application.

We encourage applicators to manage pests using integrated pest management (IPM) techniques. Before spraying pesticides, use economical and effective nonchemical methods such as cultural, mechanical, and biological control. Important goals in IPM are to properly time pesticide application to the vulnerable stage of the pest, use biorational pesticides that conserve beneficial insects, and minimize plant damage. Integrated pest management utilizes insect identification, knowledge of the pest insect's life cycle, monitoring techniques, timing insecticide application to the pest's most vulnerable stage, choosing the most appropriate pesticide, and monitoring after application.

Information on application times and dates are based on an average season; adjust timing of treatments when an early or late season is encountered. Seasonal dates apply to central Minnesota, including the Twin Cities. Expect pests approximately 7 days earlier for southern Minnesota and approximately 7–10 days later for northern Minnesota. It is the responsibility of the applicator to ensure the target pest is present before applying pesticides.

Follow all label directions carefully. Be sure the pesticide is labeled for the target site and/or plant that is intended to be treated. The availability and recommended use of specific pesticides changes over time. If suggestions in this publication differ from recommended uses on a label, the label is the final authority on how you may legally use that pesticide. It is up to the applicator to ensure pesticides are mixed, applied, and stored properly.

Pesticides are listed by common chemical name, professional product name, and consumer product name. Use of trade names does not imply endorsement. See the reference list at the end of the publication for other publications with more detailed information on specific pests.

Recently, several commonly used insecticides for the control of insects on woody landscape plants were removed from sale. EPA is phasing out the use of chlorinated hydrocarbons, organophosphates and carbamates due to safety concerns. Registration changes include:

Pest Charts

A pesticide name in Bold indicates a professional product requiring a MN Pesticide Certification and License.

Pest Hosts Pesticide Remarks
Aphids: leaf sucking, Family Aphididae, Order Homoptera
aphids: leaf sucking, exposed all trees and shrubs
  • acephate
  • azadirachtin
  • bifenthrin
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • disulfoton
  • esfenvalerate
  • fluvalinate
  • imidacloprid
  • insecticidal soap
  • lambda cyhalothrin
  • malathion
  • oil, summer spray
  • oil, dormant
  • permethrin
  • pymetrozine
  • pyrethrins
  • pyriproxyfen
Treat when aphids are numerous. Watch for evidence of aphid natural enemies (e.g. lady beetles and parasitic wasps). Insecticide treatments may not be necessary when natural enemies are abundant.
 
Pest Hosts Pesticide Remarks
Aphids: leaf curling, Family Aphididae, Order Homoptera
viburnum leaf curl aphid ash, elm, viburnum and others
  • acephate (systemic insecticide)
  • imidacloprid* (systemic insecticide)
    • Inject/drench into soil when damage is first noticed, usually in spring.
  • cyfluthrin
Spray foliage when damage is first noticed, usually in spring.
honeysuckle witches' broom aphid Tartarian, Zabel, and other susceptible varieties of honeysuckle
  • acephate (systemic insecticide)
  • imidacloprid* (systemic insecticide)
    • Inject/drench into soil when damage is first noticed, usually in spring.
  • cyfluthrin
Spray foliage when damage is first noticed, usually in spring.
 
Pest Hosts Pesticide Remarks
Aphids: woolly, Family Aphididae, Order Homoptera

aphids: leaf sucking,
woolly, exposed on branch/trunk

woolly alder aphid
woolly apple aphid

alder, silver maple, elm, apple, hawthorne, mountain ash
  • systemic insecticides
  • acephate
  • cyfluthrin
  • imidacloprid*
    • Inject/drench into soil when damage is first noticed, usually in spring.
Spray foliage when damage is first noticed in spring.

 

Pest Hosts Pesticide Remarks
Adelgid: Woolly (family Adelgidae, order Homoptera)

hemlock woolly adelgid*

hemlock
  • imidacloprid
The woolly wax reduces the efectiveness of contact insecticides. Systemic insecticides are the best choice. Use a soil drench or foliar spray of imidacloprid.
 

pine bark adelgid

White, Austrian, Scotch pine
  • dormant oil
  • carbaryl
  • chlorpyrifos (nursery only)
Improve health of tree, primarily through watering. The woolly wax reduces the effectiveness of contact insecticides. Spray bark of trunk and limbs 3 times. Dormant oil sprays (3-5%) are quite effective if applied in the fall or spring to kill the overwintering nymphs before the females have begun to produce eggs in the waxy coating. Insecticides applied in mid-April will kill the overwintering nymphs before they mature and lay eggs. Summer sprays are effective but two to three sprays, at weekly intervals, will be needed to kill new crawlers hatching from eggs.
 
Pest Hosts Pesticide Remarks
Borers: bark beetles, Family Scolytidae, Order Coleoptera

ambrosia beetle

red maples, oak, and many others
  • chlorpyrifos (nursery only)
  • permethrin
Single female galleries in pruning wounds, can vector pathogenic fungus
 

European elm bark beetle

native elm bark beetle

elms

  • chlorpyrifos (nursery only)
  • permethrin
Control native elm bark beetle at overwintering sites at the base of healthy elm trees in fall. The injection of systemic fungicides on a preventative basis, or to cure infected elms showing early stages of disease (less than 5-10% of crown symptoms). Alamo and Arbotect 20-S are trade names of two systemic fungicides that are generally effective for 2 to 3 years, but must be applied by licensed arborists.
 

pine bark beetle

pines

  • chlorpyrifos (nursery only)
  • permethrin
 
 
Pest Hosts Pesticide Remarks
Borers: clearwing borers, Family Sessidae, Order Lepidoptera

lilac/ash clearwing borer

lilac, privet, most ash
  • chlorpyrifos (nursery only)
  • permethrin
Spray on bark of trunk and limbs during adult egg laying, mid-May to June. Base timing on pheromone trap catches (available commercially).
 

banded ash clearwing borer

lilac, privet, most ash

  • chlorpyrifos (nursery only)
  • permethrin
Spray on bark of trunk and limbs during adult egg laying, August. Base timing on pheromone trap catches (available commercially).
 

viburnum borer

viburnum

  • chlorpyrifos (nursery only)
  • permethrin
Spray on bark of trunk and limbs during adult egg laying late June and July. Base timing on pheromone trap catches (available commercially).
 
Pest Hosts Pesticide Remarks
Borers: flat headed borers, Family Buprestidae, Order Coleoptera

bronze birch borer

birch (esp. paper, European white, and gray birch)
  • chlorpyrifos (nursery only)
  • permethrin
  • imidacloprid
Improve health of birch, primarily through adequate watering. Spray bark of trunk and limbs 3 times.
 

emerald ash borer*

*Not established in Minnesota as of 2003

ash
  • chlorpyrifos (nursery only)
  • permethrin
  • imidacloprid
Quarantine pest; report to MDA.
 

flat headed apple tree borer

flowering fruits, rose, cotoneaster, maple, oak, willow
  • chlorpyrifos (nursery only)
  • permethrin
  • imidacloprid
Improve health of tree, primarily through watering. Spraying bark of trunk and limbs 3 times.
 

twolined chestnut borer

oak
  • chlorpyrifos (nursery only)
  • permethrin
  • imidacloprid
Improve health of tree, primarily through watering. Spraying bark of trunk and limbs 3 times.
 
Pest Hosts Pesticide Remarks
Borers: round headed borers, Family Cerambycidae, Order Coleoptera

Asian long horn beetle*

*Not established in Minnesota as of 2003

 
  • chlorpyrifos (nursery only)
  • permethrin
Quarantine pest; report to MDA.
 

elm borer

 
  • chlorpyrifos (nursery only)
  • permethrin
Improve health of tree, primarily through watering. Spraying bark of trunk and limbs 3 times.
 

locust borer

 
  • chlorpyrifos (nursery only)
  • permethrin
Improve health of tree, primarily through watering. Spraying bark of trunk and limbs 3 times.
 

whitespotted sawyer

 
  • chlorpyrifos (nursery only)
  • permethrin
Improve health of tree, primarily through watering. Spraying bark of trunk and limbs 3 times. If beetle vectored nematode, then insecticide applications will do no good.
 
Pest Hosts Pesticide Remarks
Caterpillars: leaf feeding, many Families, Order Lepidoptera

caterpillars

virtually all trees and shrubs
  • acephate
  • Bacillus thuringiensis var. kurstaki
  • bifenthrin
  • carbaryl
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • esfenvalerate
  • fluvalinate
  • insecticidal soap
  • lambda cyhalothrin
  • malathion
  • permethrin
  • pyrethrins
  • spinosad
  • diflubenzuron
Spray leaves when caterpillars are small and before leaf damage is extensive.
 

cankerworm (spring and fall)

apple, ash, basswood boxelder, cherry, elm, maple, and others
  • as above (for caterpillars)
Late April to mid-May (at time of leaf expansion).Spray leaves when caterpillars are small and before leaf damage is extensive.
 

Eastern tent caterpillar

wild cherry, apple, crabapple, plum, pear, and others
  • as above (for caterpillars)
First active mid- to late May. Spray foliage when tents first appear, early to mid-May. Use Bacillus thuringiensis var. kurstaki when trees are flowering to protect pollinating bees.
 

fall webworm

apple, birch, black walnut, boxelder, elm, oak, willow, and many others
  • as above (for caterpillars)
Spray foliage when caterpillars are young, July to early August, but before webs are spun. Control is not effective once caterpillars are enclosed
 

forest tent caterpillar

aspen, birch, oak, basswood, ash, maple,
elm, and others
  • as above (for caterpillars)
First active mid- to late May.
 

gypsy moth*

*Not established in Minnesota as of 2003

oaks, most trees and shrubs

  • as above (for caterpillars)
  • diflubenzeuron
  • pheromone flakes

Quarantine pest; report to MDA. Larvae: May
Adults: August
Eggs: September

 

red humped caterpillar

birch, dogwood, elm, apple, and many others

  • as above (for caterpillars)

First active August to September.

 

spiny elm caterpillar

elm, willow, and others

  • as above (for caterpillars)

First active late May to early June

 

spruce budworm

balsam fir, spruce

  • as above (for caterpillars)

First active mid- to late May

 

walnut caterpillar

butternut, hickory, walnut, and others

  • as above (for caterpillars)

First active July to September.

 

white marked tussock moth

apple, basswood, elm, poplar, and others

  • as above (for caterpillars)

First active mid- to late May, second generation first active in August.

 

yellow necked caterpillar

crabapple, maple, oak, elm, and many others

  • as above (for caterpillars)

First active August to September.

 
Pest Hosts Pesticide Remarks
Caterpillars: stem boring, many Families, Order Lepidoptera

European pine shoot moth

Scot's, red, and Austrian pine
  • as above (for caterpillars)
Spray ends of branches thoroughly in mid-April or late June to early July.
 

Zimmerman pine moth

pine, especially Scot's, white, and Austrian
  • as above (for caterpillars)
  • permethrin
Spray bark of main stem, especially areas with exuding pitch, once in mid-April. Prune and destroy infected limbs. Remove pitch masses by August. Can also spray in August, although spring application is most effective.
 
Pest Hosts Pesticide Remarks
Caterpillars: leaf-feeding and case bearing, many Families, Order Lepidoptera

bagworm*

*Not established in Minnesota as of 2003

arborvitae, junipers
  • as above (for caterpillars)
Spray when bags are small.
 

elm case bearer

American elm, Siberian and
other elms
  • as above (for caterpillars)
Spray when bags are small.
 

larch casebearer

all larch species
  • as above (for caterpillars)
Spray as larch foliage appears in May and overwintering larvae begin feeding or in mid-July to August when young larvae begin mining needles.
 
Pest Hosts Pesticide Remarks
Galls: adelgid, Family Adelgidae, Order Homoptera

Galls
(induced by adelgids, cynipid wasps, eriophyid mites, gall midges, psyllids)

most trees and shrubs; found on leaves, twigs, stems, flowers, buds, and petioles   Control rarely is necessary to protect plant health. Once galls are seen, control is not effective for the current year. Identify the insect or mite and use the suggestions below as a guide.
 

Cooley spruce gall adelgid

Colorado blue and white spruce
  • carbaryl
  • bifenthrin
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • fluvalinate
  • imidacloprid
Spray spruce as buds swell in early April before galls begin to form or in September to kill over wintering adelgids.
 

Eastern spruce gall adelgid

Norway, white, and other spruce
  • carbaryl
  • bifenthrin
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • fluvalinate
  • imidacloprid
Spray spruce as buds swell in early April before galls begin to form or in late August to early September.
 
Pest Hosts Pesticide Remarks
Cynipid Galls: Family Cynipidae, Order Hymenoptera

cynipid wasp oak gall

oak bullet gall

oak rolly polly gall

jumping oak gall

mossy rose gall

spiny rose gall

oak
  • carbaryl
Spray from 1/2 to 3/4 leaf expansion.
 
Pest Hosts Pesticide Remarks
Galls: psyllids, Family Psyllidae, Order Homoptera

hackberry nipple and blister galls

oak
  • carbaryl
  • cyfluthrin
  • bifenthrin
Spray from 1/2 to 3/4 leaf expansion.
 
Pest Hosts Pesticide Remarks
Galls: eriophyid mites can be vagrant (free roaming) or make galls (erineum galls, finger galls, bladder galls, ash flower gall), Family Eriophyidae, Order Acari

maple spindle gall

maple velvet erineum gall

viburnum erineum gall

birch erineum gall

maple

maple


viburnum


birch

  • carbaryl
  • bifenthrin
Spray at or just prior to bud break.
 

ash flower gall (eriophyid mite)

ash

  • carbaryl
  • bifenthrin
Spray just prior to flower bud break in spring.
 
Pest Hosts Pesticide Remarks
Galls: fly, Family Cecidomyiidae, Family Tephrytidae, Order Diptera

tephrytid stem gall/
cecidomyiid stem gall

many
  • carbaryl
Spray from 1/2 to 3/4 leaf expansion.
 
Pest Hosts Pesticide Remarks
Leaf Beetle: leaf chewing, Family Chrysomelidae, Order Coleoptera

elm leaf beetle

American elm, Siberian and other elms
  • acephate
  • azadirachtin
  • Beauveria bassiana
  • Bacillus thuringiensis var tenebrionis
  • bifenthrin
  • carbaryl
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • fluvalinate
  • horticultural oil
  • insecticidal soap
  • imidacloprid
  • lambda cyhalothrin
  • permethrin
  • spinosad
Monitor for adult beetles in May; spray when larvae first appear. Two generations occur a year. The second generation is less damaging and less important to control.
 

cottonwood leaf beetle

poplar, willow
  • as above (for leaf beetles)
Monitor for adult beetles in May; spray when larvae first appear. Two generations occur a year. The second generation is less damaging and less important to control.
 

ninebark beetle

Diablo, Dart's Gold, American ninebark
  • as above (for leaf beetles)
Monitor for adult beetles in May; spray when larvae first appear. Two generations occur a year. The second generation is less damaging and less important to control.
 

viburnum leaf beetle*

*Not established in Minnesota as of 2003

viburnum
  • as above (for leaf beetles)
Monitor for adult beetles in May; spray when larvae first appear. One generation occur a year.
 

imported willow leaf beetle

willow, poplar, cottonwood
  • as above (for leaf beetles)
Monitor for adult beetles in May; spray when larvae first appear. Two generations occur a year. The second generation is less damaging and less important to control.
 
Pest Hosts Pesticide Remarks
Scarab beetle: leaf chewing, Family Scarabeidae, Order Coleoptera

Japanese beetle

grapes, rose, many other plants
  • acephate
  • bifenthrin
  • carbaryl
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • imidacloprid
  • lambda cyhalothrin
  • malathion
  • permethrin
Monitor for adult beetles in June and July.
 

May/June/Phyllophaga beetles

oak, grapes, lindens, Norway maple, cottonwood, many other plants
  • as above (for Japanese beetles)
Monitor for adult beetles in June and July.
 
Pest Hosts Pesticide Remarks
Leafminers: leaf mining, Famiy Tentridinidae, Order Hymeoptera

birch leafminer

gray, paper, and other birch
  • acephate
  • bifenthrin
  • carbaryl
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • disulfoton
    • can be used when damage is first noticed.
  • fenoxycarb
  • fluvalinate
  • lambda cyhalothrin
  • permethrin
  • imidacloprid*
    • Inject or drench into the soil once. Need to anticipate problem and apply the previous fall
Spray foliage thoroughly when mines first appear, about mid-May. A second generation occurs in early June, although treatment is rarely necessary.
 

elm leaf miner

Siberian elm and American elm
  • as above (for birch leafminer)
Spray foliage thoroughly when mines first appear, late April to early May.
 
Pest Hosts Pesticide Remarks
Leafhopper: leaf sucking, Family Cicadellidae, Order Homoptera

potato leafhopper

moves from potato, alfalfa, grasses to red maples
  • as above (for leaf miner)
Spray foliage, especially underside, when bugs are numerous, normally in July and August
 
Pest Hosts Pesticide Remarks
lace bug: leaf sucking, Family Tingidae, Order Homoptera

azalea lace bug* hawthorne lace bug oak lace bug

 

 

*Not established in Minnesota as of 2003

white and bur oak, hackberry, basswood,
chokecherry, juneberry, hawthorn, and others
  • acephate,
  • azadirachtin
  • bifenthrin
  • carbaryl
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • fluvalinate
  • horticultural oil
  • insecticidal soap
  • imidacloprid
  • lambda cyhalothrin
  • malathion
  • permethrin
  • pyrethrins
Spray foliage, especially underside, when bugs are numerous, normally in July and August
 
Pest Hosts Pesticide Remarks
Plant bugs: leaf sucking, Family Miridae order Homoptera

ash plant bug

most ash
  • acephate,
  • azadirachtin
  • bifenthrin
  • carbaryl
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • fluvalinate
  • horticultural oil
  • insecticidal soap
  • imidacloprid
  • lambda cyhalothrin
  • malathion
  • permethrin
  • pyrethrins
Damage is rarely extensive enough to warrant control for health of tree. Spray when bugs first appear on leaves, shortly after leaf expansion in May. Two generations occur a year.
 

fourlined plant bug

many plants, especially mints
  • as above (for ash plant bug)
Spray when bugs first appear on leaves, shortly after leaf expansion in May. One generation occurs a year.
 

honeylocust plant bug

honeylocust
  • as above (for ash plant bug)
Spray when bugs first appear on leaves, shortly after leaf expansion in May. One generation occurs a year.
 
Pest Hosts Pesticide Remarks
Sawflies: leaf chewing, Family Diprionidae(conifer) and Tenthredinidae (common), Order Hymenoptera

sawflies

many trees and shrubs
  • acephate
  • azadirachtin
  • bifenthrin
  • carbaryl
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • fluvalinate
  • horticultural oil
  • insecticidal soap
  • imidacloprid
  • lambda cyhalothrin
  • malathion
  • permethrin
  • pyrethrins
  • spinosad
Spray foliage when larvae are small (less than or equal to 1/2 full grown size) and before damage is extensive. Limit treatments to areas of plants where sawflies are feeding unless sawflies are widespread throughout the plant.
 

dogwood sawfly

dogwood, gray dogwood and other
  • as above (for sawflies)
First active June to July.
 

dusky birch sawfly

gray, paper, and other birch
  • as above (for sawflies)
First active May.
 

European pine sawfly

mugo, Scot's, and other pines
  • as above (for sawflies)
First active early to late May.
 

introduced pine
sawfly

white, and other pine
  • as above (for sawflies)
First active late May to early June and second generation. First active late July to early September.
 

larch sawfly

all larch species
  • as above (for sawflies)
First active early June to early July.
 

mountain ash sawfly

American, European mountain ash
  • as above (for sawflies)
First active June to early August. Second generation first active late August to September.
 

pear sawfly

fruit trees, hawthorn, mountain
ash, crabapple, cotoneaster, and others
  • as above (for sawflies)
First active early June. Second generation first active early August.
 

redheaded pine
sawfly

Jack, red, and other pine
  • as above (for sawflies)
First active mid-June to early July.
 

roseslug sawfly

most roses
  • as above (for sawflies)
First active mid-May to mid-June.
 

yellowheaded spruce sawfly

white, black and blue spruce
  • as above (for sawflies)
First active early to mid-June.
 
Pest Hosts Pesticide Remarks
Sawflies: stem boring, Family Tenthredinidae, Order Hymenoptera

maple petiole borer

maple, esp. sugar maple   No effective control available. Control rarely is important to protect tree health.
 
Pest Hosts Pesticide Remarks
Scales: Family Coccidae (soft scales) and Diaspididae (armored scales)

scales
armored scale
(fecal material under shell, no honeydew, overwinter as female or eggs under female cover)
soft scale
(produces honeydew,
overwinter as immature female)

any host
  • acephate
  • bifenthrin
  • carbaryl
  • chlorpyrifos (nursery only)
  • deltamethrin
  • fluvalinate
  • lambda cyhalothrin
  • horticultural oil
  • insecticidal soap
  • imidacloprid
    (only for soft scales)
  • malathion
  • permethrin
  • pyriproxyfen
Spray after crawlers have hatched. Sample to determine hatch time.
 

black pineleaf scale
(armored scale)

red, mugo, and jack pine, and Douglas fir
  • as above (for scales)
First active June to July.
 

cottony maple scale (soft scale)

maple, basswood, black locust, boxelder, elm, maple
  • as above (for scales)
  • imidacloprid
    (only for soft scales)
Crawlers first active late June to early July, repeat 10 days later.
 

European elm scale
(felt scale)

American elm and other native elm
  • as above (for scales)
  • imidacloprid
    (only for soft scales)
Crawlers first active late June to July.
 

lecanium scale
(soft scale)

many trees and shrubs
  • as above (for scales)
  • imidacloprid
    (only for soft scales)
Crawlers first active June to early July.
 

oystershell scale
(armored scale)

apple, birch, ash, cotoneaster, elm, lilac, and others
  • as above (for scales)
Crawlers first active early June.
 

pine needle scale
(armored scale)

pine, spruce
  • as above (for scales)
Crawlers first active late May.
 

pine tortoise scale
(soft scale)

Jack and Scot's pine
  • as above (for scales)
  • imidacloprid
    (only for soft scales)
Crawlers first active late June to early July.
 

scurfy scale
(armored scale)

elm, hackberry, maple, willow
  • as above (for scales)
Crawlers first active late June to early July.
 

spruce bud scale
(soft scale)

spruce
  • as above (for scales)
  • imidacloprid
    (only for soft scales)
Crawlers first active mid-June to early July.
 
Pest Hosts Pesticide Remarks
Spider Mites:Family Tetranychidae, Order Acari

spider mites

evergreens and some deciduous trees

Biorational pesticides:

  • abamectin
  • bifenazate
  • clofentazine
  • hexythiazox
  • horticultural oil
  • insecticidal soap
  • pyradiben

Conventional pesticides:

  • bifenthrin
  • chlorpyrifos (nursery only)
  • deltamethrin
  • dicofol
  • fenbutatin-oxide
  • fluvalinate
  • lambda cyhalothrin
Spray increasing mite populations before they become numerous. Use biorational pesticides that conserve beneficial insects.
 

twospotted spider mite

many deciduous trees
  • as above (for spider mites)
Spray increasing mite populations before they become numerous. Use biorational pesticides that conserve beneficial insects.
 

spruce spider mite

evergreens
  • as above (for spider mites)
Spray increasing mite populations before they become numerous. Especially serious on juniper. Use biorational pesticides that conserve beneficial insects.
 
Pest Hosts Pesticide Remarks
Twig pruners/ twig girdlers: Family Cerambycidae, Order Coleoptera

twig prunners/ twig girdlers

oak, maple, linden, flowering fruit trees,
and others

 

Prune out.
No effective control available. Control rarely is necessary to protect tree health.
 
Pest Hosts Pesticide Remarks
Weevils: stem feeding, Family Curculionidae, Order Coleoptera

white pine weevil

pine and spruce, especially white pine and Norway spruce
  • chlorpyrifos (nursery only)
  • permethrin
Spray mid- to late April. Spray only terminal portion of tree.
 
Pest Hosts Pesticide Remarks
Weevils: root feeding, Family Curculionidae, Order Coleoptera

black vine weevil

many species herbaceous plants, especially yews
  • Beauveria bassiana
  • bifenthrin
  • chlorpyrifos (nursery only)
  • cyfluthrin
  • deltamethrin
  • fluvalinate
  • imidacloprid
  • lambda cyhalothrin

larvae:

  • Beauveria bassiana
  • bifenthrin
  • imidacloprid
Spray in June, July for emerging adults; spray soil for larvae in July, August.
 

strawberry root weevil

many species herbaceous plants, especially conifer seedlings
  • as above (for black vine weevil)
Spray in June, July for emerging adults; spray soil for larvae in July, August.
 
Pest Hosts Pesticide Remarks
Weevils: trunk feeding, Family Curculionidae, Order Coleoptera

Pales weevil

white, Scotch pine; firs; spruce
  • chlorpyrifos (nursery only)
  • permethrin
Spray foliage in May, June and again in August, September to kill feeding adults.
 

Northern pine weevil

all pines, spruces
  • chlorpyrifos (nursery only)
  • permethrin
Spray foliage in May, June and again in August, September to kill feeding adults.
 

 

Insecticide names: Common name, professional product, and consumer product.

(bold indicates a professional product requiring a MN Pesticide Certification and License)

common name professional product consumer product
  • abamectin
  • Avid
  • not available
  • acephate
  • Orthene
  • Acephate Pro
  • Ortho Isotox
  • Ortho Rosepride Systemic
  • azadirachtin
  • Azatin XL
  • Safer brand 3-in-1 garden spray concentrate
  • Bonide rose rx 3 in 1
  • Bacillus thuringiensis
    var. kurstaki
  • Dipel
  • Thuricide
  • Potato-shield biological insecticide, gardens alive
  • Bacillus thuringiensis
    var. tenebrionis
  • Novodor
  • Bonide Colorado Potato Beater
  • Beauveria bassiana
  • Naturalis, Botanigard
  • not available
  • bifenazate
  • Floramite
  • not available
  • bifenthrin
  • Talstar
  • Ortho Rose & Flower
  • Ortho rtu Housplant & Garden Insect Killer
  • carbaryl
  • Sevin
  • Ortho Bug-B-Gon Garden & Landscape rtu
  • Garden Tech Sevin-10 rtu
  • chlorpyrifos
  • Chlorpyrifo Pro (nursery only)
  • not available
  • clofentezine
  • Ovation
  • not available
  • cyfluthrin
  • Tempo
  • Decathlon
  • Bayer Advanced Garden Multi-Insect Killer
  • Raid Yard Quard Fower Nozzle
  • deltamethrin
  • Deltagard
  • Bonide Delta Eight Insect Control
  • Enforcer Home Pest Control xii
  • dicofol
  • Kelthane Dow Agrosciences
  • not available
  • diflubenzuron
  • Dimilin
  • not available
  • disulfoton
  • Disyston
  • Bonide Systemic Rose & Flower Care 8-12-4
  • Bayer Advanced Garden 2 in 1 Systemic Rose & Flower rtu Granules
  • esfenvalerate
 
  • Ortho Bug-B-Gone Multipurpose Spray
  • Bonide Bug Beater rtu
  • Fenbutatin-oxide
  • Vendex
  • not available
  • fenoxycarb
  • Precision
  • not available
  • fluvalinate
  • Mavrik aquaflow
  • not available
  • hexythiazox
  • Hexygon
  • not available
  • imidacloprid
  • Merit
  • Bayer Advanced Tree & Shrub Insect Control
  • Bayer Potting Mix For Roses & Flowers 0.05-0.5-0
  • insecticidal soap
 
  • Safer’s
  • Concern
  • lambda cyhalothrin
  • Scimitar
  • Battle
  • not available
  • malathion
  • Malathion
  • Ortho Malathion Plus Insect Spray Concentrate Ornamentals
  • Ferti-lome mal-a-cide
  • oil summer spray ultra fine
  • Oil summer spray Ultra fine
  • Ferti-lome Scalecide
  • Sun Spray Ultra-Fine Year-Round Pesticidal Oil
  • oil dormant ortho fertilome
  • Oil dormant
  • Ferti-lome Dormant Spray
  • Frank's Dormant & Summer Oil Spray
  • permethrin
  • Astro
  • Ortho Bug B Gon Garden & Landscape Ready Spray
  • Bonide Borer - miner Killer Concentrate
  • pymetrozine
  • Endeavor
  • not available
  • pyradiben
  • Sanmite
  • not available
  • pyrethrins
 
  • Safer Yard & Garden Insect Killer Concentrate
  • Frank's Rose & Floral Insect Spray
  • pyriproxyfen
  • Distance
  • not available
  • spinosad
  • Conserve
  • Ferti-lome Borer, Bagworm, Leafminer & Tent Caterpillar Spray
  • Bulls Eye BioInsecticide

 


 

For additional information, see also the following University of Minnesota publications:

Birch Leafminers
The Bronze Birch Borer
Spring and Fall Cankerworms
Native Elm Bark Beetle Control
Insect and Mite Galls
Leaf Beetles in Urban Landscapes
Sawflies of Trees and Shrubs
Scale Insects of Trees and Shrubs

 

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