University of Kentucky College of Agriculture
ENTFACT-447

Calendar for Common Kentucky Shade Tree and Woody Ornamental Pests

by Lee Townsend, Extension Entomologist
University of Kentucky College of Agriculture

 

This calendar shows many of the common insects and mites that feed on shade trees and woody ornamentals in Kentucky. It should be helpful in anticipating pest activity or in identifying potential pests when trying to diagnose problems during the season. The pests are listed alphabetically by month, in most cases with information on where to look for them (usually on the foliage). For pests such as scales and borers, there is information on when the vulnerable stage is active rather than when the more visible adults are present. The “When to look” column indicates when the feeding stages should be present. Pests with multiple generations appear more than once on the calendar. This publication has been prepared to serve as an aid in evaluating landscape plantings for pests, it is not intended to be a spray schedule.

 

The geographical and seasonal weather variations across Kentucky will result in pests appearing sooner or later in a particular year. Both plant and insect development are temperature-dependent so seasonal appearance of particular pests should follow a predictable sequence that correlates with the flowering of particular landscape plants. More accurate predictions can be made by using ENT-66, “Timing control actions for landscape insect pests using flowering plants as indicators”. The information in ENT-66 will help you to know when to check plants for pests and to schedule control measures more effectively. ENT or Entfact publications for specific pests are listed below the pest name so that you can get more detailed information. If none are listed, you can look in other references.

 

March

Pest

Where to look / treat

When to look

Maple gall mites

Maple twigs and buds (preventive)

late March through early April

Snowball aphid

Viburnum

mid-March through mid-April

Spruce spider mite

Needles and twigs of conifers

mid-March through April

White pine aphid

White pine needles - terminal foliage

late March to mid-April

April

Aphids

New growth and lower leaf surface

mid-April to early May

Cankerworms

Foliage of beech, elm, maple, oaks, and others

April through May

Eastern tent caterpillar

Branch crotches of cherry, crabapples, apple and related

early April to mid-May

Euonymus scale

Twigs and stems of Euonymus, Pyracantha, Pachysandra

several generations

late April through August

European pine sawfly

Mugho, Scotch, other pines

April through mid-June

Holly leaf miner

Upper and lower holly leaf surfaces

late April through early May

Honeylocust plant bug

Foliage of honeylocust and black locust

mid-April through May

Lilac borer

Lilac trunk and branches, especially by wounds

First flight late April

Locust leaf miner

Locust foliage

June

Pine needle scale

Needles of pines, especially Mugho and Scotch, spruce and other conifers

Crawlers in late April to early May

San Jose Scale

Twigs and bark

Crawlers late April, several generations

Woolly alder aphid

Silver maple

April

Yellow poplar weevil

Poplar, sassafras, and magnolia

April and May

May

Azalea lace bug

Azaleas, especially evergreen varieties and mountain laurel

May and July

Bagworm

Foliage of host, especially arbovitae, juniper

mid-May through mid-June

Birch leaf miner

Birch

early May and mid-June

Boxwood leaf miner

Boxwood foliage

mid-May through mid-June

Boxwood psyllid

Underside of boxwood leaves

mid-May to mid-June

Bronze birch borer

Bark, especially upper branches of birch

late May to early June

Dogwood borer

Dogwood trunks and branches

May to mid-June

Elm leaf beetle

Elm

mid-May through early July

European red mite

Foliage of host

May through June

Fall webworm

Tents at end of branches in various trees

late May through June

Juniper scale

Juniper and arbovitae twigs and branches

Egg hatch in May

Linden looper

Oaks, maples, elm, hickory, ash

May through June

Oystershell scale

Twigs and branches of willow, lilac, apple, others

Crawlers in early May

Pine bark adelgid

Twigs and branches of white and Scotch pines

early to mid-May but several generations

Pine webworm

Va pine, short and longleaf pines

May

Poplar tentmaker

Poplar and willow

May through October

Taxus mealybug

Trunk and branches of Taxus, apple, cedar, linden, maple

Active in late May, 2 to 3 generations/year

Walnut caterpillar

Black walnut, pecan, hickory

May

White pine aphid

White pine terminal needles

 mid-May

Yellow poplar weevil

Poplar, sassafrass, and magnolia

mid-May

June

Birch leaf miner

Birch foliage

mid-June

Dogwood sawfly

Dogwood

June through July

Introduced pine sawfly

White, red, Scotch, Austrian and other pines

June

Leafhoppers

Foliage of many trees, especially redbud

June

Locust leaf miner

Locust

June

Mimosa webworm

Mimosa

mid -June

Nantucket pine tip moth

Pine leaders

early June

Oak skeletonizer

Oaks

June

Redheaded pine sawfly

Pine needles

mid-June through Sept, 2 to 3 generations/year

Rose slugs

Rose leaves

mid-June

Spruce needle miner

Spruce

June through hard frost

July

Azalea lace bug

Azaleas, especially evergreen and mountain laurel

July

European hornet

Twigs of lilac, birch, rhododendron

July through early Sept

Fall webworm

Tents at end of branches in various trees

 mid- to late July

Japanese beetle

Foliage of host

July through August

Orangestriped oakworm

Red and white oaks

July through September

Pine needle scale

Needles of pines, especially Mugho and Scots, spruce and other conifers

mid- to late July

Rose slugs

Rose leaves

mid-July through mid-August

Spiny oakworm

Red and white oaks

July through September

Two spotted spider mite

Underside of leaves, many plants

mid-July through mid-August

Woolly alder aphid

Alder

June through September

August

Locust leaf miner

Locust

August

Mimosa webworm

Mimosa

August

Oak skeletonizer

Oaks

August

Pine webworm

Va pine, short and longleaf pines

August

Tuliptree scale

Tuliptree twigs and branches

Crawlers in late August

September

Cottony maple scale

Twigs of maple honeylocust others

Crawlers in early September

Magnolia scale

Magnolia twigs and branches

Crawlers in early September

Spruce spider mite

Needles and twigs of conifers

September

 

Issued: 1/03
Revised: 1/03

 

CAUTION! Pesticide recommendations in this publication are registered for use in Kentucky, USA ONLY! The use of some products may not be legal in your state or country. Please check with your local county agent or regulatory official before using any pesticide mentioned in this publication.

 

Of course, ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR SAFE USE OF ANY PESTICIDE!

 

Photos courtesy Ric Bessin, University of Kentucky Entomology