University of Maryland Extension

Pest Predictive Calendar-Landscape/Nursery

The Pest Predictive Calendar is a monitoring tool to assist in predicting when susceptible life stage(s) (stage you want to target for control measures) of pest insects are active by using plant phenological indicators (PPI) and growing degree days (GDD). This tool will lead to improved timing of management tactics and more effective pest management.

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Phenological sequence of plant flowering and insect events with their associated GDD in Maryland. For more information go to: How to Use the Pest Predictive Calendar and Getting and Using Growing Degree Days.
Plant/Pest Common Name
Taxonomic Name
Phenological Event
Persian speedwellVeronica persicafirst bloom16
Corneliancherry dogwoodCornus masfirst bloom22
Red mapleAcer rubrumfirst bloom34
Border forsythiaForsythia x intermediafirst bloom35
Euonymus leaf-notcher caterpillarPryeria sinicaegg hatch37
Red mapleAcer rubrumfull bloom42
Callery pear (MD Tier 2 Invasive Plant)Pyrus calleryanafirst bloom50
Eastern tent caterpillarMalacosoma americanumegg hatch51
Purple deadnettleLamium purpureumfirst bloom52
Border forsythiaForsythia x intermediafull bloom53
Saucer magnoliaMagnolia x soulangeanafirst bloom59
Star magnoliaMagnolia stellatafirst bloom89
Flowering quinceChaenomeles speciosafirst bloom103
Bridal wreath spireaSpirea x vanhoutteifirst bloom104
Callery pear (MD Tier 2 Invasive Plant)Pyrus calleryanafull bloom105
SassafrasSassafras albidumfirst bloom122
Bridal wreath spireaSpirea x vanhoutteifull bloom123
Eastern redbudCercis canadensisfirst bloom137
SassafrasSassafras albidumfull bloom138
Double weeping higan cherryPrunus shubhirtella 'Pendula Plena Rosa'first bloom142
Eastern redbudCercis candensisfull bloom156
Fernald’s shadbushAmelanchier fernaldiifull bloom163
Nantucket serviceberryAmelanchier nantucketensisfull bloom171
Spiny witchhazel gall aphidHamamelistes spinosusadult/nymph171
Serviceberry 'Autumn Brilliance'Amelanchier x grandiflorafirst bloom179
Double weeping higan cherryPrunus subhirtella 'Pendula Plena Rosa'full bloom195
Mountain pierisPieris floribundafull bloom197
White enkianthusEnkianthus perulatus 'JL Pennock'full bloom204
Serviceberry 'Autumn Brilliance'Amelanchier x grandiflorafull bloom235
Boxwood leafminerMonarthropalpusi flavusadult emergence249
Crabapple 'Adirondack'Malus 'Adirondack'first bloom260
Dwarf azaleaRhododendron atlanticumfirst bloom260
MayapplePodophyllum peltatumfirst bloom264
Spruce spider miteOligonychus ununguisadult/nymph276
Dogwood 'Appalachian Spring'Cornus florida 'Appalachian Spring'first bloom281
Pine needle scaleChionaspis pinifoliaeegg hatch (1st gen)283
Hemlock woolly adelgidAdelges tsugaeegg hatch (1st gen)300
Sheep laurelKalmia angustifolia 'Royal Dwarf'first bloom314
Spirea aphidAphis spiraecolaadult/nymph326
Lilac borerPodosesia syringaeadult emergence350
Black locustRobinia pseudoacaciafirst bloom357

Dogwood 'Appalachian Spring'

Cornus florida 'Appalachian Spring'full bloom358

Hawthorn 'Winter King'

Crataegus viridis 'Winter King'first bloom358
Pinxterbloom azaleaRhododendron periclymenoidesfull bloom360
Crabapple 'Adirondack'Malus 'Adirondack'full bloom379
Black locustRobinia pseudoacaciafull bloom386
Red horsechestnutAesculus x carnea 'Ft. McNair'first bloom389
Emerald ash borerAgrilus planipennisadult emergence421 
Blue false indigoBaptisia australis 'Purple Smoke'first bloom431
Basswood lace bugGargaphia tiliaeadult/nymph462
Lesser peachtree borerSynanthedon pictipesadult emergence (1st gen)468
Maskell scaleLepidosaphes pallidaegg hatch (1st gen)470
Virginia spiderwortTradescantia virginianafirst bloom494
Gypsy mothLymantria disparegg hatch
Red horsechestnutAesculus x carnea 'Ft. McNair'full bloom511
Hawthron 'Winter King'Crataegus viridis 'Winter King'full bloom515
Euonymus scaleUnaspis euonymiegg hatch (1st gen)522
American smoketreeCotinus obovatusfull bloom575
Common ninebarkPhysocarpus opulifolius ‘Luteus’full bloom583
Yellow flag iris (Maryland Tier 1 invasive plant)Iris pseudacorusfirst bloom587 
Clematis 'Westerplatte'Clematis ‘Westerplatte’full bloom589
White prunicola scalePsedaulacaspis prunicolaegg hatch (1st gen)594
American yellowwoodCladrastis kentukeafirst bloom600
BagwormThyridopteryx ephemeraeformisegg hatch602
American yellowwoodCladrastis kentukeafull bloom627
Virginia spiderwortTradescantia virginianafull bloom692
Juniper scaleCarulaspis juniperiegg hatch694
Cottony camellia/Taxus scalePulvinaria flocciferaegg hatch773
Oak leacanium scaleParthenolecanium quercifexegg hatch773
Japanese maple scaleLopholeucaspis japonicaegg hatch (1st gen)829 
Cottony camellia/taxus scalePulvinaria flocciferaegg hatch856
SmoketreeCotinus coggygria full bloom866
Calico scaleEulecanium cerasorumegg hatch887
Japanese stewartiaStewartia pseudocameliafirst bloom908
Smooth witherod/Possumhaw viburnumViburnum nudum ‘Winterthur’full bloom1002
Mimosa WebwormHomadaula anisocentraegg hatch (1st gen)1002
Japanese stewartiaStewartia pseudocameliafull bloom1027
Japanese beetlePopillia japonicaadult emergence1056
Fletcher scaleParthenolecanium fletcheriegg hatch1105
Bottlebrush buckeyeAesculus parviflorafirst bloom1137
Indian wax scaleCeraplastes ceriferusegg hatch1145
Cryptomeria scaleAspidiotus cryptomeriaeegg hatch (1st gen)1190
Cottony maple scalePulvinaria innumerabilisegg hatch1194
Bottlebrush buckeyeAesculus parviflorafull bloom1200
MimosaAlbizia julibrissinfirst bloom1215
Butterfly weedAsclepias tuberosafirst bloom1216
MimosaAlbizia julibrissinfull bloom1330
BeebalmMonarda sppfirst bloom1380
GoldenraintreeKoelreuteria paniculatafirst bloom1393
Satin blue Rose-of-SharonHibiscus syriacus 'Satin Blue'first bloom1492
Swamp milkweedAsclepias incarnatafirst bloom1510
Fall webwormHyphantria cuneaegg hatch (1st gen)1530
Pine needle scaleChionaspis pinifoliaeegg hatch (2nd gen)1537
Green June beetleCotinus nitidaadult emergence1539
Obscure scaleMelanaspis obscuraegg hatch1567
GoldenraintreeKoelreuteria paniculatafull bloom1597
White prunicola scalePsedaulacaspis prunicolaegg hatch (2nd gen)1637
Satin blue Rose-of-SharonHibiscus syriacus 'Satin Blue'full bloom1742
Orangestriped oakwormAnisota senatoriaegg hatch (early instar)1969
Maskell scaleLepidosaphes pallidaegg hatch (2nd gen)2035
Regent pagodatreeStyphnolobrium japonicumfirst bloom2204
Euonymus scaleUnaspis euonymiegg hatch (2nd gen)2235 
Regent pagodatreeStyphnolobrium japonicumfull bloom2330
Crimsoneyed rosemallowHibiscus moscheutosfirst bloom2464
Hollow joe pye weedEutrochium fistulosum
first bloom2494
Japanese maple scaleLopholeucaspis japonicaegg hatch (2nd gen)2508
Natchez crape myrtleLagerstromia x 'Natchez'full bloom2617
Crimsoneyed rosemallowHibiscus moscheutosfull bloom2704
Seven-son flowerHeptacodium miconioidesfirst bloom2770
Fall webwormHyphantria cuneaegg hatch (2nd gen)2793
Seven-son flowerHeptacodium miconioidesfull bloom3072
White prunicola scalePsedaulacaspis prunicolaegg hatch (3rd gen)3270
Banded ash clearwing borerPodosesia aureocinctaadult emergence3357
Tuliptree scaleToumeyella liriodendriegg hatch3519
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