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FO-0704-GO
Reviewed 1999
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Insecticide Suggestions to Manage Landscape Tree and Shrub Insects

Jeffrey D. Hahn, Robert P. Wawrzynski and Vera Krischik

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Copyright  ©  1999  Regents of the University of Minnesota. All rights reserved.
Table of Contents
How To Use This Publication

Pest Charts 		Pest Charts (cont'd) Common Names of Active
Ingredients & Common Trade Names

Additional Information/Publications

How To Use This Publication

This publication provides information on insecticide options when an insect pest problem is identified. 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. Integrated pest management promotes monitoring, correct identification, and knowledge of the pest insect's life cycle. All practical, economical, and effective nonchemical methods (including cultural, mechanical, and biological) should be considered first before insecticides are applied. An important goal in IPM is to minimize plant damage.

Discussion of application times and suggested dates in this publication are based on an average season. Adjust timing of treatments when an early or late season is encountered. Dates listed for spring 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 treating.

The pesticides listed in this publication are common names of active ingredients. They are found on the label under the heading Active Ingredients . These names are often listed in fine print so check carefully. Common examples of trade names are given at the end of this publication strictly for convenience. Use of trade names does not imply endorsement.

Follow all label directions carefully. Be sure the pesticide is labelled for the target site and/or plant that is intended to be treated. The availability and recommended use of specific pesticides may change at anytime. 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.

This publication lists insecticide options available to commercial applicators and the general public. Active ingredients that are available to commercial applicators only are marked with an asterisk (*). These insecticides are not available to the general public.

A footnote using a letter indicates there is a publication available concerning that insect (see below). A footnote using a number indicates there are additional comments on that subject which will be found on the last row of each table.

Pest Hosts Pesticide Timing/Remarks
Aphids (general) virtually all trees and shrubs acephate
bifenthrin*
chlorpyrifos
diazinon
dimethoate
endosulfan
fluvalinate*
imidacloprid*
insecticidal soap 1
lambda-cyhalothrin*
malathion
permethrin
pyrethrins 1 		Treat when aphids are numerous. Watch for evidence of aphid natural enemies (e.g. ladybird beetles and parasitic wasps). Insecticide treatments may not be necessary when natural enemies are abundant.
Leaf-curling aphids viburnum and others acephate
dimethoate 		Spray foliage when damage is first noticed, usually in spring.
oxydementon-methyl* Inject into soil once when damage is first noticed, usually in spring.
imidacloprid* Inject or drench into soil once. Need to anticipate problem and apply the previous fall.
Honeysuckle witches' broom aphids Tartarian, Zabel, and other susceptible varieties of honeysuckle acephate
dimethoate 		Spray 3 times 2 to protect the plant's health or 5 times 3 to protect the plant's appearance.
oxydementon-methyl* Inject into soil once about third week of May.
imidacloprid* Inject or drench into soil once. Need to anticipate problem and apply the previous fall.
Wooly aphids ash, elm, silver maple, juneberry, alder acephate
dimethoate 		Spray foliage when damage is first noticed, usually in spring.
oxydementon-methyl* Inject into soil once, when damage is first noticed, usually in spring.
imidacloprid* Inject or drench into soil once. Need to anticipate problem and apply the previous fall.
*For commercial use only; not available to public.

1 This insecticide has no residual activity and repeat treatments may be necessary.

2 Spray about the first week of June, the first week of July and first week of August.

3 Spray approximately the third week of May, the second week of June, the first week of July, the fourth week of July, and the third week of August.

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Pest Hosts Pesticide Timing/Remarks
Ash borer lilac, privet, most ash chlorpyrifos
lindane
permethrin* 		Spray on bark of trunk and limbs during adult egg laying, mid-May to June. Base timing on pheromone trap catches (available commercially).
*For commercial use only; not available to public.

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Pest Hosts Pesticide Timing/Remarks
Ash plant bug most ash acephate
bifenthrin*
carbaryl
chlorpyrifos
cyfluthrin*
lambda-cyhalothrin*
permethrin* 		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.
*For commercial use only; not available to public.

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Pest Hosts Pesticide Timing/Remarks
Birch leafminer a gray, paper, and other birch acephate
dimethoate 		Spray foliage thoroughly when mines first appear, about mid-May. A second generation occurs in early June, although treatment is rarely necessary.
dimethoate Paint trunk at bud break.
oxydementon-methyl* Inject into soil when mines first appear.
imidacloprid* Inject or drench into the soil once. Need to anticipate problem and apply the previous fall.
*For commercial use only; not available to public.

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Pest Hosts Pesticide Timing/Remarks
Bronze birch borer b birch (esp. paper, European white, and gray birch) bendiocarb*
chlorpyrifos
lindane
permethrin* 		Improve health of birch, primarily through adequate watering. Spray bark of trunk and limbs 3 times 4 .
*For commercial use only; not available to public.

4 Spray approximately the third week of May, the second week of June, and the first week of July.

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Pest Hosts Pesticide Timing/Remarks
Caterpillars virtually all trees and shrubs (see below) acephate
azadirachtin
( Bacillus thuringiensis var. kurstaki 5 )
bifenthrin*
carbaryl
cyfluthrin*
diazinon
diflubenzuron*
fluvalinate*
insecticidal soap 1
lambda-cyhalothrin*
malathion
permethrin
phosmet
pyrethrins 1 		Spray leaves when caterpillars are small and before leaf damage is extensive.
Cankerworms (spring and fall) c apple, ash, basswood, boxelder, cherry, elm, maple, and others (see caterpillars)
also: bendiocarb* 		Late April to mid-May (at time of leaf expansion).
oxydementon-methyl* Inject into soil (same time as spray).
Eastern tent caterpillar wild cherry, apple, crabapple, plum, pear, and others (see caterpillars)
also: bendiocarb* 		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 (see caterpillars)
also: bendiocarb* 		Spray foliage when caterpillars are young, July to early August, but before webs are spun. Control is not effective once caterpillars are enclosed in web.
Forest tent caterpillar aspen, birch, oak, basswood, ash, maple, elm, and others (see caterpillars) First active mid- to late May.
Red-humped caterpillar birch, dogwood, elm, apple, and many others (see caterpillars) First active August to September.
Spiny elm caterpillar elm, willow, and others (see caterpillars) First active late May to early June.
Spruce budworm balsam fir, spruce (see caterpillars) First active mid- to late May.
Walnut caterpillar butternut, hickory, walnut, and others (see caterpillars) First active July to September.
White-marked tussock moth apple, basswood, elm, poplar, and others (see caterpillars) First active mid- to late May, second generation first active in August.
Yellow-necked caterpillar crabapple, maple, oak, elm, and many others (see caterpillars)
also: bendiocarb* 		First active August to September.
*For commercial use only; not available to public.

1 This insecticide has no residual activity and repeat treatments may be necessary.

5 Bacillus thuringiensis variety kurstaki is most effective when young caterpillars are treated. It is not effective against older caterpillars or adult moths or butterflies.

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Pest Hosts Pesticide Timing/Remarks
Elm bark beetle d American elm and other elm carbaryl
chlorpyrifos
lindane
methoxychlor
permethrin* 		For control of feeding adults. Not recommended for control of Dutch elm disease. Control native elm bark beetle at overwintering sites at the base of healthy elm trees in fall.
*For commercial use only; not available to public.

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Pest Hosts Pesticide Timing/Remarks
Elm leafminer Siberian elm and American elm dimethoate Spray foliage thoroughly when mines first appear, late April to early May.
oxydementon-methyl* Inject into soil about third week of May.
imidacloprid* Inject or drench into soil once. Need to anticipate problem and treat the previous fall.
*For commercial use only; not available to public.

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Pest Hosts Pesticide Timing/Remarks
European pine shoot moth Scot's, red, and Austrian pine bifenthrin*
carbaryl
chlorpyrifos
cyfluthrin*
diazinon
lambda-cyhalothrin*
permethrin* 		Spray ends of branches thoroughly in mid-April or late June to early July.
*For commercial use only; not available to public.

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Pest Hosts Pesticide Timing/Remarks
Flat-headed apple tree borer maple, oak, willow, rose, cotoneaster bendiocarb*
chlorpyrifos
lindane
permethrin* 		Keep trees in vigorous growing condition. Spray bark of trunk and limbs 3 times 4 .
*For commercial use only; not available to public.

4 Spray approximately the third week of May, the second week of June, and the first week of July.

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Pest Hosts Pesticide Timing/Remarks
Galls
(induced by cynipid wasps, eriophyid mites, psyllids, gall midges and adelgids e, f ) 		most trees and shrubs; found on leaves, twigs, stems, flowers, buds, and petioles (see below) 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.
Mite galls (eriophyid mites) maple, elm, ash, hackberry, and many others carbaryl
dicofol 		Spray at or just prior to bud break.
Ash flower gall (eriophyid mite) ash carbaryl
dicofol 		Spray just prior to flower bud break in spring.
Cynipid wasp galls oak acephate
carbaryl
lambda-cyhalothrin* 		Spray from 1/2 to 3/4 leaf expansion.
Hackberry nipple and blister galls (psyllids) hackberry acephate
dimethoate 		Spray from 1/2 to 3/4 leaf expansion.
Midge galls many carbaryl
cyfluthrin*
lambda-cyhalothrin*
malathion
permethrin 		Spray from 1/2 to 3/4 leaf expansion.
Cooley spruce gall (adelgid) Colorado blue and white spruce acephate
carbaryl
diazinon
imidacloprid*
insecticidal soap 1
lambda-cyhalothrin*
paraffinic oil 1 		Spray spruce as buds swell in early April before galls begin to form or in September to kill overwintering adelgids.
imidacloprid* Inject or drench into soil once. Need to anticipate problem and apply the previous fall.
Eastern spruce gall (adelgids) Norway, white, and other spruce acephate
carbaryl
diazinon
imidacloprid*
insecticidal soap 1
lambda-cyhalothrin*
paraffinic oil 1 		Spray spruce as buds swell in early April before galls begin to form or in late August to early September.
imidacloprid* Inject or drench into soil once. Need to anticipate problem and apply the previous fall.
*For commercial use only; not available to public.

1 This insecticide has no residual activity and repeat treatments may be necessary.

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Pest Hosts Pesticide Timing/Remarks
Honeylocust plant bug honeylocust acephate
bifenthrin*
carbaryl
diazinon
lambda-cyhalothrin*
paraffinic oil 1
permethrin 		Spray when leaves first expand.
*For commercial use only; not available to public.

1 This insecticide has no residual activity and repeat treatments may be necessary.

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Pest Hosts Pesticide Timing/Remarks
Lace bugs white and bur oak, hackberry, basswood, chokecherry, juneberry, hawthorn, and others acephate
bifenthrin*
carbaryl
chlorpyrifos
cyfluthrin*
imidacloprid*
insecticidal soap 1
lambda-cyhalothrin*
paraffinic oil 1
permethrin*
pyrethrins 1 		Spray foliage, especially underside, when bugs are numerous, normally in July and August.
imidacloprid* Inject or drench into soil once. Need to anticipate problem and apply in early spring or previous fall.
*For commercial use only; not available to public.

1 This insecticide has no residual activity and repeat treatments may be necessary.

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Pest Hosts Pesticide Timing/Remarks
Larch casebearer all larch species acephate
methoxychlor 		Spray as larch foliage appears in May and overwintering larvae begin feeding or in mid-July to August when young larvae begin mining needles.

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Pest Hosts Pesticide Timing/Remarks
Leaf beetles g (see below) acephate
( Bacillus thuringiensis var. tenebrionis 6 )
bendiocarb*
bifenthrin*
carbaryl
chlorpyrifos
cyfluthrin*
fluvalinate*
imidacloprid*
lambda-cyhalothrin*
permethrin*
phosmet
pyrethrins 1 		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.
imidacloprid* Inject or drench into soil once. Need to anticipate problems and apply the previous fall.
Elm leaf beetle American elm, Siberian and other elms (see leaf beetles) (see leaf beetles)
oxydementon-methyl* Inject into soil about third week of May.
Imported willow leaf beetle willow, poplar, cottonwood (see leaf beetles) (see leaf beetles)
Cottonwood leaf beetle poplar, willow (see leaf beetles) (see leaf beetles)
*For commercial use only; not available to public.

1 This insecticide has no residual activity and repeat treatments may be necessary.

6 Bacillus thuringiensis variety tenebrionis is most effective against young larvae and is not effective against older larvae or adult beetles.

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Pest Hosts Pesticide Timing/Remarks
Lilac/Ash borer lilac, privet, most ash chlorpyrifos
lindane
permethrin* 		Spray on bark of trunk and limbs during adult egg laying, mid-May to June. Base timing on pheromone trap catches (available commercially).
*For commercial use only; not available to public.

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Pest Hosts Pesticide Timing/Remarks
Maple petiole borer maple, esp. sugar maple
No effective control available. Control rarely is important to protect tree health.

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Pest Hosts Pesticide Timing/Remarks
Sawflies h many trees and shrubs
(see below) 		acephate
carbaryl
chlorpyrifos
cyfluthrin*
diazinon
imidacloprid*
insecticidal soap 1
lambda-cyhalothrin*
malathion
paraffinic oil 1 		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 gray dogwood and other dogwood (see sawflies) First active June to July.
Dusky birch sawfly gray, paper, and other birch (see sawflies) First active May.
European pine sawfly mugo, Scot's, and other pine (see sawflies) First active early to late May.
Introduced pine sawfly white, and other pine (see sawflies) First active late May to early June and second generation first active late July to early September.
Larch sawfly all larch species (see sawflies) First active early June to early July.
Mountain ash sawfly American, European, and other mountain ash (see sawflies) First active June to early August. Second generation first active late August to September.
Redheaded pine sawfly Jack, red, and other pine (see sawflies) First active mid-June to early July.
Roseslug sawfly most roses (see sawflies) First active mid-May to mid-June.
Pear sawfly fruit trees, hawthorn, mountain ash, crabapple, cotoneaster, and others (see sawflies) First active early June. Second generation first active early August.
Yellowheaded spruce sawfly white, black and blue spruce (see sawflies) First active early to mid-June.
*For commercial use only; not available to public.

1 This insecticide has no residual activity and repeat treatments may be necessary.

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Pest Hosts Pesticide Timing/Remarks
Scales i (see below) acephate
bifenthrin*
carbaryl
chlorpyrifos
cyfluthrin*
insecticidal soap 1
lambda-cyhalothrin*
malathion
paraffinic oil 1 		Spray after crawlers have hatched. Sample to determine hatch time 7 .
imidacloprid* Inject or drench into soil once. Need to anticipate problem and apply the previous fall.
Black pine-leaf scale red, mugo, and jack pine, and Douglas fir (see scales) Crawlers first active mid-June to mid-July.
Cottony maple scale maple, basswood, black locust, boxelder, elm, maple (see scales) Crawlers first active late June to early July, repeat 10 days later.
European elm scale American elm and other native elm (see scales) Crawlers first active late June to July.
Lecanium scale many trees and shrubs (see scales) Crawlers first active June to early July.
Oystershell scale apple, birch, ash, cotoneaster, elm, lilac, and others (see scales) Crawlers first active early June.
Pine needle scale pine, spruce (see scales) Crawlers first active late May 8 . If using paraffinic oil, apply two weeks after egg hatch.
Pine tortoise scale Jack and Scot's pine (see scales) Crawlers first active late June to early July.
Scurfy scale elm, hackberry, maple, willow (see scales) Crawlers first active late June to early July.
Spruce bud scale spruce (see scales) Crawlers first active mid-June to early July.
*For commercial use only; not available to public.

1 This insecticide has no residual activity and repeat treatments may be necessary.

7 Adult scales are very difficult to control. Treatment is most effective during the crawler stage.

8 Check again in July and August for crawlers; there is a scale species closely related to pine needle scale that has a second generation later in the summer.

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Pest Hosts Pesticide Timing/Remarks
Spider mites evergreens and some deciduous trees avermectin*
bifenthrin*
dicofol
dimethoate
fluvalinate*
hexakis 9
hexythiazox*
insecticidal soap 1
lambda-cyhalothrin*
oxythioquinox* 		Spray increasing mite populations before they become numerous. Especially serious on juniper.
*For commercial use only; not available to public.

1 This insecticide has no residual activity and repeat treatments may be necessary.

9 May be combined with acephate.

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Pest Hosts Pesticide Timing/Remarks
Twig pruner oak, maple, linden, flowering fruit trees, and others
No effective control available. Control rarely is necessary to protect tree health.

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Pest Hosts Pesticide Timing/Remarks
Twolined chestnut borer oak, ironwood bendiocarb*
chlorpyrifos
lindane
permethrin* 		Improve health of tree, primarily through watering. Spraying bark of trunk and limbs 3 times 4 .
*For commercial use only; not available to public.

4 Spray approximately the third week of May, the second week of June, and the first week of July.

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Pest Hosts Pesticide Timing/Remarks
White pine weevil pine and spruce, especially white pine and Norway spruce bendiocarb*
chlorpyrifos
lindane
permethrin* 		Spray mid- to late April. Spray only terminal portion of tree.
*For commercial use only; not available to public.

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Pest Hosts Pesticide Timing/Remarks
Zimmerman pine moth pine, especially Scot's, white, and Austrian chlorpyrifos
endosulfan
lindane
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.
*For commercial use only; not available to public.

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Index of Common Names of Active Ingredients with Example(s) of Common Trade Names

acephate Orthene hexakis Vendex
avermectin Avid hexythiazox Hexygon
azadirachtin Margosan-O fluvalinate Mavrik
Bacillus thuringiensis
var. kurstaki 		Dipel, Thuricide imidacloprid Merit
Bacillus thuringiensis
var. tenebrionis 		M-One insecticidal soap M-Pede, Safer's
bendiocarb Dycarb, Turcam lambda-cyhalothrin Scimitar
bifenthrin Talstar lindane Lindane
carbaryl Sevin, Sevimol malathion Malathion
chlorpyrifos Dursban, Pageant methoxychlor Marlate, Methoxychlor
cyfluthrin Tempo 2 oxydementon-methyl Metasystox-R 2
diazinon Diazinon oxythioquinox Morestan
dicofol Kelthane paraffinic oils
(petroleum distillates) 		Sunspray 6E
diflubenzuron Dimilin permethrin Astro
dimethoate Cygon phosmet Imidan
endosulfan Thiodan pyrethrins Pyrenone

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For additional information, see also the following
University of Minnesota publications:
a Birch Leafminers FS-6134
b The Bronze Birch Borer FS-1417
c Spring and Fall Cankerworms FS-0876
d Native Elm Bark Beetle Control FS-1420
e Insect and Mite Galls FS-1009
f Insect and Mite Galls in the Landscape FO-6704
g Leaf Beetles in Urban Landscapes FS-6342
h Sawflies of Landscape Trees and Shrubs FO-6703
i Scale Insects of Trees and Shrubs FO-1019

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Jeffrey D. Hahn
assistant extension entomologist
Department of Entomology 		Robert P. Wawrzynski
research fellow
Department of Entomology 		Vera Krischik
assistant professor
Department of Entomology
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Information source: University of Minnesota Extension Service.

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