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!
