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 Name Taxonomic Name Phenological Event GDD Links
Red maple Acer rubrum first bloom 12 F, A, P
Persian speedwell Veronica persica first bloom 16 A, P
Corneliancherry dogwood Cornus mas first bloom 22 A
Red maple Acer rubrum full bloom 27  
Border forsythia  Forsythia x intermedia first bloom 35 P
Euonymus leaf-notcher caterpillar Pryeria sinica egg hatch 37 A
Callery pear (MDA - Tier 2 invasive plant) Pyrus calleryana (hybrids so there will be some variation) first bloom 50 A, P
Purple deadnettle Lamium purpureum first bloom 52 P
Border forsythia Forsythia x intermedia full bloom 53 P
Saucer magnolia Magnolia x soulangeana first bloom 59 F
Spicebush Lindera benzoin first bloom 72 A, P
Bloodroot Sanguinaria canadensis first bloom 79  
White pine weevil Pissodes strobi adult first activity 84¹ A
Eastern tent caterpillar Malacosoma americanum egg hatch 86 A, P
Star magnolia Magnolia stellata first boom 89 P
Flowering quince Chaenomeles speciosa first bloom 103 P
Bridal wreath spirea Spirea x vanhouttei first bloom 104 P, A
Callery pear (MDA - Tier 2 invasive plant) Pyrus calleryana (hybrids so there will be some variation) full bloom 105 P
Spicebush Lindera benzoin full bloom 108 F, A
Koreanspice viburnum Viburnum carlesii first bloom 117 F, A
Sargent's cherry Prunus sargentii first bloom 121 A
Sassafras Sassafras albidum first bloom 122 A
Bridal wreath spirea Spirea x vanhouttei full bloom 123 A
Japanese camellia 'Jerry Hill' Camellia japonica 'Jerry Hill' first bloom 131  
Eastern redbud Cercis canadensis first bloom 137 A
Sassafras Sassafras albidum full bloom 138 A
Sargent's cherry Prunus sargentii full bloom 140 A
Boxwood spider mite Eurytetranchus buxi egg hatch 141 F
Double weeping higan cherry Prunus subhirtella 'Pendula Plena Rosa' first bloom 142 A
Cherry laurel Prunus laurocerasus first bloom 144 A
Koreanspice viburnum Viburnum carlesii full bloom 149 A
Red buckeye Aesculus pavia first bloom 154 A
Canadian serviceberry Amelanchier canadensis first bloom 154 A
European pine sawfly Neodiprion sertifer larva, early instar 154 F
Eastern redbud Cercis canadensis full bloom 162 A
Fernald's shadbush Amelanchier fernaldii full bloom 163  
Woolly elm aphid Eriosoma americana egg hatch 163 A, P
Inkberry holly leafminer Phytomyza glabricola adult emergence 165² A
Nantucket serviceberry Amelanchier nantucketensis full bloom 171 P
Spiny witchhazel gall aphid Hamamelistes spinosus adult/nymph 171 F, P
Serviceberry 'Autumn Brilliance' Amelanchier x grandiflora first bloom 179 A
Spruce spider mite Oligonychus ununguis egg hatch 179 A
Boxwood psyllid Psylla buxi egg hatch 184² P
Double weeping higan cherry Prunus subhirtella 'Pendula Plena Rosa' full bloom 195 A
Tea scale Fiorinia theae egg hatch/crawler (1st gen) 195 A
Mountain pieris Pieris floribunda full bloom 197 A
Hemlock woolly adelgid Adelges tsugae egg hatch (1st gen) 197 A
Japanese camellia 'Jerry Hill' Camellia japonica 'Jerry Hill' full bloom 201  
White enkianthus Enkianthus perulatus 'JL Pennock' full bloom 204  
Viburnum leaf beetle Pyrrhalta viburni first egg hatch 210¹ A
Slender deutzia Deutzia gracilus Nikko first bloom 211 A
Azalea lace bug Stephanitis pyrioides egg hatch (1st gen) 214 F
Birch leafminer Fenusa pusilla adult emergence 215¹ F
Elm leafminer Fenusa ulmi adult emergence 219¹ F
Roseslug sawfly Endelomyia aethiops egg hatch/early instar 230 A
Honeylocust plant bug Diaphnocoris chlorionis egg hatch 230¹ A
Elongate hemlock scale Fiorinia externa egg hatch/ crawler (1st gen) 232 A
Serviceberry 'Autumn Brilliance' Amelanchier x grandiflora full bloom 235 A
Boxwood leafminer Monarthropalpusi flavus adult emergence 249 P
Hawthorn lace bug Corythucha cydoniae first adult activity 259 F
Crabapple 'Adirondack' Malus 'Adirondack' first bloom 260 A
Dwarf azalea Rhododendron atlanticum first bloom 260 A
Mayapple Podophyllum peltatum first bloom 264 A
Spotted lanternfly Lycorma delicatula egg hatch 270³ A
Dogwood 'Appalachian Spring' Cornus florida 'Appalachian Spring' first bloom 281 A
Bristly roseslug sawfly Cladius difformis larva, early instar 284 F
Imported willow leaf beetle Plagiodera versicolora adult emergence 290 F
Hawthorn leafminer Profenusa canadensis adult emergence 292²  
Andromeda lace bug Stephanitis takeyai egg hatch 305 F
Pine needle scale Chionaspis pinifoliae egg hatch/crawler 307 F, A, P
Cooley spruce gall adelgid Adelges cooleyi egg hatch 308¹ F, A
Eastern spruce gall adelgid Adelges abietis egg hatch 308¹ F, A
Sheep laurel Kalmia angustifolia 'Royal Dwarf' first bloom 314 A
Red buckeye Aesculus pavia full bloom 324 A
Spirea aphid Aphis spiraecola adult/nymph 326 A
Lilac borer Podosesia syringae adult emergence 350 A
Melon aphid Aphis gossypii adult/nymph 351 A
Black locust Robinia pseudoacacia first bloom 357 A
Dogwood 'Appalachian Spring' Cornus florida 'Appalachian Spring' full bloom 358 A
Hawthorn 'Winter King' Crataegus viridis 'Winter King' first bloom 358 F, A
Pinxterbloom azalea Rhododendron periclymenoides full bloom 360 A
Spongy moth (formerly gypsy moth) Lymantria dispar egg hatch 373 A
Holly leafminer Phytomyza ilicis adult emergence 375¹ F
Crabapple 'Adirondack' Malus 'Adirondack' full bloom 379 A
Red horsechestnut Aesculus x carnea 'Ft. McNair' first bloom 389 A
Hemlock woolly adelgid Adelges tsugae egg hatch (2nd gen) 411  
Basswood lace bug Gargaphia tiliae 1st adult activity 415 A
Black locust Robinia pseudoacacia full bloom 417 A
Emerald ash borer Agrilus planipennis adult emergence 421 A, A
Locust leafminer Odontota dorsalis adult emergence 429 A
Blue false indigo Baptisia australis 'Purple Smoke' first bloom 431 A
Honeylocust plant bug Blepharidopterus chlorionis egg hatch, early instar 433  
Fourlined plant bug Poecilocapsus lineatus egg hatch/early instar 435 F
Lesser peachtree borer Synanthedon pictipes adult emergence (1st gen) 468 A
Oak erricoccin scale (oak felt scale) Acanthococcus quercus (formerly Eriococcus quercus) egg hatch/crawler 469 P
Maskell scale Lepidosaphes pallida egg hatch/crawler (1st gen) 470 A, P
Thornless honeylocust 'Skyline' Gleditsia triacanthos f. inermis 'Skycole' SKYLINE first bloom 472 A
Japanese snowbell Styrax japonicus first bloom 477 A
Oystershell scale Lepidosaphes ulmi egg hatch/crawler (1st gen) 486 F, A
Tuliptree Liriodendron tulipifera first bloom 490 A
Virginia spiderwort Tradescantia virginiana first bloom 494 A
Tuliptree Liriodendron tulipifera full bloom 509 A
Red horsechestnut Aesculus x carnea 'Ft. McNair' full bloom 511 A
Minute cypress scale Carulaspis minima egg hatch/crawler 511  
White prunicola scale Psedaulacaspis prunicola egg hatch/crawler (1st gen) 513 F, P
Hawthorn 'Winter King' Crataegus viridis 'Winter King' full bloom 515 F, A
Euonymus scale Unaspis euonymi egg hatch/crawler (1st gen) 522 F
Bronze birch borer Agrilus anxius adult emergence 547¹ F, A
American smoketree Cotinus obovatus full bloom 575 A
Chinese fringetree Chionanthus retusus full bloom 576  
Common ninebark Physocarpus opulifolius ‘Luteus’ full bloom 583 A
Clematis ‘Westerplatte’ Clematis ‘Westerplatte’ full bloom 589  
Thornless honeylocust 'Sklyline' Gleditsia triacanthos f. inermis 'Skycole' SKYLINE full bloom 597 A
American yellowwood Cladrastis kentukea first bloom 600 A
Yellow flag iris (Maryland Tier 1 invasive plant) Iris pseudacorus first bloom 601 A
Potato leafhopper Empoasca fabae adult arrival 603 A
Black vine weevil Otiorhynchus sulcatus adult emergence 607¹ F
American yellowwood Cladrastis kentukea full bloom 627 A
Twospotted spider mite Tetranychus urticae egg hatch 627¹ F
Bagworm Thyridopteryx ephemeraeformis egg hatch 635 A, A
Crapemyrtle bark scale Acanthococcus lagerstroemiae egg hatch (1st gen) 638 A
Cottony camellia/Taxus scale Pulvinaria floccifera egg hatch/crawler 649 F, A
Mimosa webworm Homadaula anisocentra larva, early instar (1st gen) 674 F, A
Japanese snowball Styrax japonicus full bloom 677 A
Virginia spiderwort Tradescantia virginiana full bloom 692 A
Chinese dogwood Cornus kousa full bloom 693  
Juniper scale Carulaspis juniperi egg hatch/crawler 694 F, A
Calico scale Eulecanium cerasorum egg hatch/crawler 765 A
Oak lecanium scale Parthenolecanium quercifex egg hatch/crawler 789 A
Granat astilbe Astilbe x arendsii 'Granat' first bloom 791  
Rhododendron borer Synanthedon rhododendri adult emergence 815¹ F
Japanese maple scale Lopholeucaspis japonica egg hatch/crawler (1st gen) 829 F
Dogwood borer Synanthedon scitula adult emergence 830¹ A
European elm scale Gossyparia surplus egg hatch/crawler 831 A
Smoketree Cotinus coggygria  full bloom 866 A
Goat's beard Aruncus dioecus full bloom 872  
Cottony maple scale Pulvinaria innumerabilis egg hatch/crawler 872 A
Winged euonymus scale Lepidosaphes yanangicola egg hatch/crawler 892¹ A
European fruit lecanium scale Parthenolecanium corni egg hatch/crawler 904 A
Japanese stewartia Stewartia pseudocamellia first bloom 908 A
Cryptomeria scale Aspidiotus cryptomeriae egg hatch/crawler 937 A
Azalea bark scale Eriococcus azaleae egg hatch/crawler 957¹ F
Smooth witherod/Possumhaw viburnum Viburnum nudum ‘Winterthur’ full bloom 1002 A
Hibiscus sawfly Atomacera decepta larva (early instar) 1015 F
Japanese beetle Popillia japonica adult emergence 1026 A
Japanese stewartia Stewartia pseudocamellia full bloom 1027 A
Fletcher scale Parthenolecanium fletcheri egg hatch/crawler 1105 F, P
Spotted lanternfly Lycorma delicatula adult flight 1112³ A
Bottlebrush buckeye Aesculus parviflora first bloom 1137 A
Fall webworm Hyphantria cunea egg hatch (1st gen) 1142 A, A
Indian wax scale Ceraplastes ceriferus egg hatch/crawler 1145 F
Oriental beetle Anomala orientalis adult emergence 1147 F
Granat astilbe Astilbe x arendsii 'Granat' full bloom 1167  
Peachtree borer Synanthedon exitiosa adult emergence 1181 F
Butterfly bush Buddleia hemsleyana first bloom 1197  
Bottlebrush buckeye Aesculus parviflora full bloom 1200 A
Mimosa Albizia julibrissin first bloom 1215 A
Butterfly weed Asclepias tuberosa first bloom 1216 A
Mimosa Albizia julibrissin full bloom 1330 A
Catalpa sphinx Ceratomia catalpa egg hatch (1st gen) 1365 A
Beebalm Monarda spp first bloom 1380 A
Goldenraintree Koelreuteria paniculata first bloom 1393 A
Satin blue Rose-of-Sharon Hibiscus syriacus 'Satin Blue' first bloom 1492 A
Swamp milkweed Asclepias incarnata first bloom 1510 A
Green June beetle Cotinus nitida adult emergence 1539 F
Scarlet oak slug sawfly Caliroa quercuscoccineae larva (early instar) 1544 P
Pine needle scale Chionaspis pinifoliae egg hatch/crawler (2nd gen) 1561 F
Goldenraintree Koelreuteria paniculata full bloom 1597 A
White prunicola scale Psedaulacaspis prunicola egg hatch/crawler (2nd gen) 1637

F
Satin blue Rose-of-Sharon Hibiscus syriacus 'Satin Blue' full bloom 1742 A
Obscure scale Melanaspis obscura egg hatch/crawler 1774 F, A
Spotted lanternfly Lycorma delicatula egg laying 1825³ A
Orangestriped oakworm Anisota senatoria egg hatch/early instar 1917 F, A
Magnolia scale Neolecanium cornuparvum crawler 1938¹ F, A
Fall webworm Hyphantria cunea egg hatch/early instar (2nd gen) 1962  
Maskell scale Lepidosaphes pallida egg hatch/crawler (2nd gen) 2035 A, P
Regent pagodatree Styphnolobrium japonicum first bloom 2111 A
Euonymus scale Unaspis euonymi egg hatch/crawler (2nd gen) 2235  
Crape myrtle 'Natchez' Lagerstroemia x 'Natchez' first bloom 2251 A
Mimosa webworm Homadaula anisocentra larva,early instar (2nd gen) 2260 A
Regent pagodatree Styphnolobrium japonicum full bloom 2330 A
Crimsoneyed rosemallow Hibiscus moscheutos first bloom 2464 A
Hollow Joe pye weed Eutrochium fistulosum first bloom 2494 A, A
Japanese maple scale Lopholeucaspis japonica egg hatch/crawler (2nd gen) 2508 F
Crape myrtle 'Natchez' Lagerstroemia x 'Natchez' full bloom 2617 A
Crimsoneyed rosemallow Hibiscus moscheutos full bloom 2704 A
Seven-son flower Heptacodium miconioides first bloom 2770 A
Fern scale Pinnaspis aspidistrae egg hatch/crawler (2nd gen) 2813 F
Seven-son flower Heptacodium miconioides full bloom 3072 A
White prunicola scale Psedaulacaspis prunicola egg hatch/crawler (3rd gen) 3238 F
Banded ash clearwing borer Podosesia aureocincta adult emergence 3357 A
Tuliptree scale Toumeyella liriodendri egg hatch/crawler 3472 A

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
⁴ Adults migrate from the South with winds - timing can vary