Pest Predictive Calendar for Landscapes and Nurseries

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.

A = Article     F = Fact Sheet      P = links to a UMD Extension page with multiple images or non-UMD pages

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 NameTaxonomic NamePhenological EventGDDLinks
Red mapleAcer rubrumfirst bloom12F, A, P
Persian speedwellVeronica persicafirst bloom16A, P
Corneliancherry dogwoodCornus masfirst bloom22A
Red mapleAcer rubrumfull bloom27 
Border forsythia Forsythia x intermediafirst bloom35P
Euonymus leaf-notcher caterpillarPryeria sinicaegg hatch37A
Callery pear (MDA - Tier 2 invasive plant)Pyrus calleryana (hybrids so there will be some variation)first bloom50A, P
Purple deadnettleLamium purpureumfirst bloom52P
Border forsythiaForsythia x intermediafull bloom53P
Saucer magnoliaMagnolia x soulangeanafirst bloom59F
SpicebushLindera benzoinfirst bloom72A, P
BloodrootSanguinaria canadensisfirst bloom79 
White pine weevilPissodes strobifirst adult activity84¹A
Eastern tent caterpillarMalacosoma americanumegg hatch86A, P
Star magnoliaMagnolia stellatafirst boom89P
Flowering quinceChaenomeles speciosafirst bloom103P
Bridal wreath spireaSpirea x vanhoutteifirst bloom104P, A
Callery pear (MDA - Tier 2 invasive plant)Pyrus calleryana (hybrids so there will be some variation)full bloom105P
SpicebushLindera benzoinfull bloom108F, A
Koreanspice viburnumViburnum carlesiifirst bloom117F, A
Sargent's cherryPrunus sargentiifirst bloom121A
SassafrasSassafras albidumfirst bloom122A
Bridal wreath spireaSpirea x vanhoutteifull bloom123A
Japanese camellia 'Jerry Hill'Camellia japonica 'Jerry Hill'first bloom131 
Eastern redbudCercis canadensisfirst bloom137A
SassafrasSassafras albidumfull bloom138A
Sargent's cherryPrunus sargentiifull bloom140A
Boxwood spider miteEurytetranchus buxiegg hatch141F
Double weeping higan cherryPrunus subhirtella 'Pendula Plena Rosa'first bloom142A
Cherry laurelPrunus laurocerasusfirst bloom144A
Koreanspice viburnumViburnum carlesiifull bloom149A
Red buckeyeAesculus paviafirst bloom154A
Canadian serviceberryAmelanchier canadensisfirst bloom154A
European pine sawflyNeodiprion sertiferlarva, early instar154F
Eastern redbudCercis canadensisfull bloom162A
Fernald's shadbushAmelanchier fernaldiifull bloom163 
Woolly elm aphidEriosoma americanaegg hatch163A, P
Inkberry holly leafminerPhytomyza glabricolaadult emergence165²A
Nantucket serviceberryAmelanchier nantucketensisfull bloom171P
Spiny witchhazel gall aphidHamamelistes spinosusadult/nymph171F, P
Serviceberry 'Autumn Brilliance'Amelanchier x grandiflorafirst bloom179A
Spruce spider miteOligonychus ununguisegg hatch179A
Boxwood psyllidPsylla buxiegg hatch184²P
Double weeping higan cherryPrunus subhirtella 'Pendula Plena Rosa'full bloom195A
Tea scaleFiorinia theaeegg hatch/crawler (1st gen)195A
Mountain pierisPieris floribundafull bloom197A
Hemlock woolly adelgidAdelges tsugaeegg hatch (1st gen)197A
Japanese camellia 'Jerry Hill'Camellia japonica 'Jerry Hill'full bloom201 
White enkianthusEnkianthus perulatus 'JL Pennock'full bloom204 
Viburnum leaf beetlePyrrhalta viburnifirst egg hatch210¹A
Slender deutziaDeutzia gracilus Nikkofirst bloom211A
Azalea lace bugStephanitis pyrioidesegg hatch (1st gen)214F
Birch leafminerFenusa pusillaadult emergence215¹F
Elm leafminerFenusa ulmiadult emergence219¹F
Roseslug sawflyEndelomyia aethiopslarva/early instar230A
Elongate hemlock scaleFiorinia externaegg hatch/ crawler (1st gen)232A
Serviceberry 'Autumn Brilliance'Amelanchier x grandiflorafull bloom235A
Boxwood leafminerMonarthropalpusi flavusadult emergence249P
Hawthorn lace bugCorythucha cydoniaefirst adult activity259F
Crabapple 'Adirondack'Malus 'Adirondack'first bloom260A
Dwarf azaleaRhododendron atlanticumfirst bloom260A
MayapplePodophyllum peltatumfirst bloom264A
Spotted lanternflyLycorma delicatulaegg hatch270³A
Dogwood 'Appalachian Spring'Cornus florida 'Appalachian Spring'first bloom281A
Bristly roseslug sawflyCladius difformislarva, early instar284F
Imported willow leaf beetlePlagiodera versicoloraadult emergence290F
Hawthorn leafminerProfenusa canadensisadult emergence292² 
Andromeda lace bugStephanitis takeyaiegg hatch305F
Pine needle scaleChionaspis pinifoliaeegg hatch/crawler307F, A, P
Cooley spruce gall adelgidAdelges cooleyiegg hatch308¹F, A
Eastern spruce gall adelgidAdelges abietisegg hatch308¹F, A
Sheep laurelKalmia angustifolia 'Royal Dwarf'first bloom314A
Red buckeyeAesculus paviafull bloom324A
Spirea aphidAphis spiraecolaadult/nymph326A
Lilac borerPodosesia syringaeadult emergence350A
Melon aphidAphis gossypiiadult/nymph351A
Black locustRobinia pseudoacaciafirst bloom357A
Dogwood 'Appalachian Spring'Cornus florida 'Appalachian Spring'full bloom358A
Hawthorn 'Winter King'Crataegus viridis 'Winter King'first bloom358F, A
Spiny ash sawflyEupareophora parcalarva, early instar358A
Pinxterbloom azaleaRhododendron periclymenoidesfull bloom360A
Spongy moth (formerly gypsy moth)Lymantria disparegg hatch373A
Holly leafminerPhytomyza ilicisadult emergence375¹F
Crabapple 'Adirondack'Malus 'Adirondack'full bloom379A
Red horsechestnutAesculus x carnea 'Ft. McNair'first bloom389A
Hemlock woolly adelgidAdelges tsugaeegg hatch (2nd gen)411A
Basswood lace bugGargaphia tiliaefirst adult activity415A
Black locustRobinia pseudoacaciafull bloom417A
Emerald ash borerAgrilus planipennisadult emergence421A, A
Locust leafminerOdontota dorsalisadult emergence429A
Blue false indigoBaptisia australis 'Purple Smoke'first bloom431A
Honeylocust plant bugBlepharidopterus (Diaphnocoris) chlorionisegg hatch, early instar433A
Fourlined plant bugPoecilocapsus lineatusegg hatch/early instar435F
Lesser peachtree borerSynanthedon pictipesadult emergence (1st gen)468A
Oak erricoccin scale (oak felt scale)Acanthococcus quercus (formerly Eriococcus quercus)egg hatch/crawler469P
Maskell scaleLepidosaphes pallidaegg hatch/crawler (1st gen)470A, P
Thornless honeylocust 'Skyline'Gleditsia triacanthos f. inermis 'Skycole' SKYLINEfirst bloom472A
Japanese snowbellStyrax japonicusfirst bloom477A
Oystershell scaleLepidosaphes ulmiegg hatch/crawler (1st gen)486²F, A
TuliptreeLiriodendron tulipiferafirst bloom490A
Virginia spiderwortTradescantia virginianafirst bloom494A
TuliptreeLiriodendron tulipiferafull bloom509A
Red horsechestnutAesculus x carnea 'Ft. McNair'full bloom511A
Minute cypress scaleCarulaspis minimaegg hatch/crawler511F
White prunicola scalePsedaulacaspis prunicolaegg hatch/crawler (1st gen)513F, P
Hawthorn 'Winter King'Crataegus viridis 'Winter King'full bloom515F, A
Euonymus scaleUnaspis euonymiegg hatch/crawler (1st gen)522F
Bronze birch borerAgrilus anxiusadult emergence547¹F, A
American smoketreeCotinus obovatusfull bloom575A
Chinese fringetreeChionanthus retususfull bloom576 
Common ninebarkPhysocarpus opulifolius ‘Luteus’full bloom583A
Clematis ‘Westerplatte’Clematis ‘Westerplatte’full bloom589 
Thornless honeylocust 'Sklyline'Gleditsia triacanthos f. inermis 'Skycole' SKYLINEfull bloom597A
American yellowwoodCladrastis kentukeafirst bloom600A
Yellow flag iris (Maryland Tier 1 invasive plant)Iris pseudacorusfirst bloom601A
Potato leafhopperEmpoasca fabaeadult arrival603A
Black vine weevilOtiorhynchus sulcatusadult emergence607¹F
American yellowwoodCladrastis kentukeafull bloom627A
Twospotted spider miteTetranychus urticaeegg hatch627¹F
BagwormThyridopteryx ephemeraeformisegg hatch635A, A
Cottony camellia/Taxus scalePulvinaria flocciferaegg hatch/crawler649F, A
Mimosa webwormHomadaula anisocentralarva, early instar (1st gen)674F, A
Japanese snowballStyrax japonicusfull bloom677A
Virginia spiderwortTradescantia virginianafull bloom692A
Chinese dogwoodCornus kousafull bloom693 
Juniper scaleCarulaspis juniperiegg hatch/crawler694F, A
San Jose scaleQuadraspidiotus perniciosusegg hatch/crawler (1st gen)723A
Crapemyrtle bark scaleAcanthococcus lagerstroemiaeegg hatch (1st gen)724A
Calico scaleEulecanium cerasorumegg hatch/crawler765A
Oak lecanium scaleParthenolecanium quercifexegg hatch/crawler789A
Granat astilbeAstilbe x arendsii 'Granat'first bloom791 
Rhododendron borerSynanthedon rhododendriadult emergence815¹F
Japanese maple scaleLopholeucaspis japonicaegg hatch/crawler (1st gen)829F
Dogwood borerSynanthedon scitulaadult emergence830¹A
European elm scaleGossyparia surplusegg hatch/crawler831A
SmoketreeCotinus coggygria full bloom866A
Goat's beardAruncus dioecusfull bloom872 
Cottony maple scalePulvinaria innumerabilisegg hatch/crawler872A
Winged euonymus scaleLepidosaphes yanangicolaegg hatch/crawler892¹A
European fruit lecanium scaleParthenolecanium corniegg hatch/crawler904A
Japanese stewartiaStewartia pseudocamelliafirst bloom908A
Cryptomeria scaleAspidiotus cryptomeriaeegg hatch/crawler937A
Azalea bark scaleEriococcus azaleaeegg hatch/crawler957¹F
Smooth witherod/Possumhaw viburnumViburnum nudum ‘Winterthur’full bloom1002A
Hibiscus sawflyAtomacera deceptalarva, early instar1015F
Japanese beetlePopillia japonicaadult emergence1026A
Japanese stewartiaStewartia pseudocamelliafull bloom1027A
Fletcher scaleParthenolecanium fletcheriegg hatch/crawler1105F, P
Spotted lanternflyLycorma delicatulafirst adult activity1112³A
Bottlebrush buckeyeAesculus parviflorafirst bloom1137A
Fall webwormHyphantria cuneaegg hatch (1st gen)1142A, A
Indian wax scaleCeraplastes ceriferusegg hatch/crawler1145F
Oriental beetleAnomala orientalisadult emergence1147F
Granat astilbeAstilbe x arendsii 'Granat'full bloom1167 
Peachtree borerSynanthedon exitiosaadult emergence1181F
Butterfly bushBuddleia hemsleyanafirst bloom1197 
Bottlebrush buckeyeAesculus parviflorafull bloom1200A
MimosaAlbizia julibrissinfirst bloom1215A
Butterfly weedAsclepias tuberosafirst bloom1216A
MimosaAlbizia julibrissinfull bloom1330A
Catalpa sphinxCeratomia catalpaegg hatch (1st gen)1365A
BeebalmMonarda sppfirst bloom1380A
GoldenraintreeKoelreuteria paniculatafirst bloom1393A
Satin blue Rose-of-SharonHibiscus syriacus 'Satin Blue'first bloom1492A
Swamp milkweedAsclepias incarnatafirst bloom1510A
Green June beetleCotinus nitidaadult emergence1539F
Scarlet oak slug sawflyCaliroa quercuscoccineaelarva, early instar1544P
Pine needle scaleChionaspis pinifoliaeegg hatch/crawler (2nd gen)1561F
GoldenraintreeKoelreuteria paniculatafull bloom1597A
White prunicola scalePsedaulacaspis prunicolaegg hatch/crawler (2nd gen)1637F
Satin blue Rose-of-SharonHibiscus syriacus 'Satin Blue'full bloom1742A
Obscure scaleMelanaspis obscuraegg hatch/crawler1774F, A
Spotted lanternflyLycorma delicatulaegg laying1825³A
Orangestriped oakwormAnisota senatoriaegg hatch/early instar1917F, A
Magnolia scaleNeolecanium cornuparvumcrawler1938¹F, A
Fall webwormHyphantria cuneaegg hatch/early instar (2nd gen)1962A, A
Maskell scaleLepidosaphes pallidaegg hatch/crawler (2nd gen)2035A, P
Regent pagodatreeStyphnolobrium japonicumfirst bloom2111A
Euonymus scaleUnaspis euonymiegg hatch/crawler (2nd gen)2235F
Crape myrtle 'Natchez'Lagerstroemia x 'Natchez'first bloom2251A
Mimosa webwormHomadaula anisocentralarva,early instar (2nd gen)2260A
Regent pagodatreeStyphnolobrium japonicumfull bloom2330A
Crimsoneyed rosemallowHibiscus moscheutosfirst bloom2464A
Hollow Joe pye weedEutrochium fistulosumfirst bloom2494A, A
Japanese maple scaleLopholeucaspis japonicaegg hatch/crawler (2nd gen)2508F
Crape myrtle 'Natchez'Lagerstroemia x 'Natchez'full bloom2617A
Crimsoneyed rosemallowHibiscus moscheutosfull bloom2704A
Seven-son flowerHeptacodium miconioidesfirst bloom2770A
Fern scalePinnaspis aspidistraeegg hatch/crawler (2nd gen)2813F
Seven-son flowerHeptacodium miconioidesfull bloom3072A
White prunicola scalePsedaulacaspis prunicolaegg hatch/crawler (3rd gen)3238F
Banded ash clearwing borerPodosesia aureocinctaadult emergence3357A
Tuliptree scaleToumeyella liriodendriegg hatch/crawler3472A

¹ Source: Average Degree Days (DD) Ohio State University (OSU) research data
² Source:  Average DD using UMD research data combined with OSU research data
³ Source: Liu et al. 2020
Adults migrate from the South with winds - timing can vary