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  
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  
Spicebush Lindera benzoin first bloom 72  
White pine weevil Pissodes strobi adult first activity 84* 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
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  
Koreanspice viburnum Viburnum carlesii first bloom 117  
Sargent's cherry Prunus sargentii first bloom 121 A
Sassafras Sassafras albidum first bloom 122  
Bridal wreath spirea Spirea x vanhouttei full bloom 123  
Eastern redbud Cercis canadensis first bloom 137  
Sassafras Sassafras albidum full bloom 138  
Sargent's cherry Prunus sargentii full bloom 140 A
Double weeping higan cherry Prunus subhirtella 'Pendula Plena Rosa' first bloom 142  
Cherry laurel Prunus laurocerasus first bloom 144  
Koreanspice viburnum Viburnum carlesii full bloom 149  
Red buckeye Aesculus pavia first bloom 154  
Canadian serviceberry Amelanchier canadensis first bloom 154  
European pine sawfly Neodiprion sertifer larva, early instar 154 A
Eastern redbud Cercis canadensis full bloom 162  
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 165**  
Nantucket serviceberry Amelanchier nantucketensis full bloom 171  
Spiny witchhazel gall aphid Hamamelistes spinosus adult/nymph 171 F, P
Serviceberry 'Autumn Brilliance' Amelanchier x grandiflora first bloom 179  
Spruce spider mite Oligonychus ununguis egg hatch 179 A
Boxwood psyllid Psylla buxi egg hatch 184** P
Double weeping higan cherry Prunus subhirtella 'Pendula Plena Rosa' full bloom 195  
Mountain pieris Pieris floribunda full bloom 197  
White enkianthus Enkianthus perulatus 'JL Pennock' full bloom 204  
Viburnum leaf beetle Pyrrhalta viburni first egg hatch 210* A, A
Slender deutzia Deutzia gracilus Nikko first bloom 211  
Azalea lace bug Stephanitis pyrioides egg hatch (1st gen) 214 A
Birch leafminer Fenusa pusilla adult emergence 215* A
Elm leafminer Fenusa ulmi adult emergence 219* A
Roseslug sawfly Endelomyia aethiops egg hatch/early instar 230 A
Honeylocust plant bug Diaphnocoris chlorionis egg hatch 230*  
Serviceberry 'Autumn Brilliance' Amelanchier x grandiflora full bloom 235  
Hemlock woolly adelgid Adelges tsugae egg hatch (1st gen) 235  
Boxwood leafminer Monarthropalpusi flavus adult emergence 249 P
Crabapple 'Adirondack' Malus 'Adirondack' first bloom 260  
Dwarf azalea Rhododendron atlanticum first bloom 260  
Mayapple Podophyllum peltatum first bloom 264  
Hawthorn lace bug Corythucha cydoniae first adult activity 265 F
Dogwood 'Appalachian Spring' Cornus florida 'Appalachian Spring' first bloom 281  
Bristly roseslug sawfly Cladius difformis larva, early instar 284  
Imported willow leaf beetle Plagiodera versicolora adult emergence 290 F
Hawthorn leafminer Profenusa canadensis adult emergence 292**  
Andromeda lace bug Stephanitis takeyai egg hatch 305 A
Pine needle scale Chionaspis pinifoliae egg hatch/crawler 307 A, P
Cooley spruce gall adelgid Adelges cooleyi egg hatch 308* A
Eastern spruce gall adelgid Adelges abietis egg hatch 308* A
Sheep laurel Kalmia angustifolia 'Royal Dwarf' first bloom 314  
Red buckeye Aesculus pavia full bloom 324  
Spirea aphid Aphis spiraecola adult/nymph 326 A
Lilac borer Podosesia syringae adult emergence 350 A
Black locust Robinia pseudoacacia first bloom 357  
Dogwood 'Appalachian Spring' Cornus florida 'Appalachian Spring' full bloom 358  
Hawthorn 'Winter King' Crataegus viridis 'Winter King' first bloom 358  
Pinxterbloom azalea Rhododendron periclymenoides full bloom 360  
Spongy moth (formerly gypsy moth) Lymantria dispar egg hatch 373 A
Holly leafminer Phytomyza ilicis adult emergence 375* F
Crabapple 'Adirondack' Malus 'Adirondack' full bloom 379  
Red horsechestnut Aesculus x carnea 'Ft. McNair' first bloom 389  
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  
Emerald ash borer Agrilus planipennis adult emergence 421  
Locust leafminer Odontota dorsalis adult emergence 429 A
Blue false indigo Baptisia australis 'Purple Smoke' first bloom 431  
Fourlined plant bug Poecilocapsus lineatus egg hatch/early instar 435 F, F
Lesser peachtree borer Synanthedon pictipes adult emergence (1st gen) 468 A
Maskell scale Lepidosaphes pallida egg hatch/crawler (1st gen) 470  
Thornless honeylocust 'Skyline' Gleditsia triacanthos f. inermis 'Skycole' SKYLINE first bloom 472  
Japanese snowbell Styrax japonicus first bloom 477  
Oystershell scale Lepidosaphes ulmi egg hatch/crawler (1st gen) 486 A, F
Tuliptree Liriodendron tulipifera first bloom 490  
Honeylocust plant bug

Blepharidopterus chlorionis

egg hatch, early instar 433  
Virginia spiderwort Tradescantia virginiana first bloom 494  
Tuliptree Liriodendron tulipifera full bloom 509  
Red horsechestnut Aesculus x carnea 'Ft. McNair' full bloom 511  
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  
Euonymus scale Unaspis euonymi egg hatch/crawler 522  
Bronze birch borer Agrilus anxius adult emergence 547* A
Black vine weevil Otiorhynchus sulcatus adult emergence 560* F
American smoketree Cotinus obovatus full bloom 575  
Common ninebark Physocarpus opulifolius ‘Luteus’ full bloom 583  
Clematis ‘Westerplatte’ Clematis ‘Westerplatte’ full bloom 589  
Thornless honeylocust 'Sklyline' Gleditsia triacanthos f. inermis 'Skycole' SKYLINE full bloom 597  
American yellowwood Cladrastis kentukea first bloom 600  
Yellow flag iris (Maryland Tier 1 invasive plant) Iris pseudacorus first bloom 601 A
Bagworm Thyridopteryx ephemeraeformis egg hatch 602  
American yellowwood Cladrastis kentukea full bloom 627  
Twospotted spider mite Tetranychus urticae egg hatch 627* F
Cottony camellia/Taxus scale Pulvinaria floccifera egg hatch 649 A
Mimosa webworm Homadaula anisocentra larva, early instar (1st gen) 674 F, A
Japanese snowball Styrax japonicus full bloom 677  
Virginia spiderwort Tradescantia virginiana full bloom 692  
Juniper scale Carulaspis juniperi egg hatch 694 F, A
Calico scale Eulecanium cerasorum egg hatch/crawler 765 A
Oak lecanium scale Parthenolecanium quercifex egg hatch/crawler 789 A
Rhododendron borer Synanthedon rhododendri adult emergence 815* F
Japanese maple scale Lopholeucaspis japonica egg hatch/crawler (1st gen) 829 F
Dogwood borer Synanthedon scitula adult emergence 830*  
European elm scale Gossyparia surplus egg hatch/crawler 831  
Smoketree Cotinus coggygria  full bloom 866  
Cottony maple scale Pulvinaria innumerabilis egg hatch/crawler 872 A
Winged euonymus scale Lepidosaphes yanangicola egg hatch/crawler 892*  
European fruit lecanium scale Parthenolecanium corni egg hatch/crawler 904  
Japanese stewartia Stewartia pseudocamellia first bloom 908  
Cryptomeria scale Aspidiotus cryptomeriae egg hatch/crawler 937  
Azalea bark scale Eriococcus azaleae egg hatch/crawler 957* F
Smooth witherod/Possumhaw viburnum Viburnum nudum ‘Winterthur’ full bloom 1002  
Japanese stewartia Stewartia pseudocamellia full bloom 1027  
Japanese beetle Popillia japonica adult emergence 1056  
Fletcher scale Parthenolecanium fletcheri egg hatch/crawler 1105 F, P
Bottlebrush buckeye Aesculus parviflora first bloom 1137  
Fall webworm Hyphantria cunea egg hatch (1st gen) 1142  
Indian wax scale Ceraplastes ceriferus egg hatch/crawler 1145 F
Oriental beetle Anomala orientalis adult emergence 1147  
Peachtree borer Synanthedon exitiosa adult emergence 1181 F
Bottlebrush buckeye Aesculus parviflora full bloom 1200  
Mimosa Albizia julibrissin first bloom 1215  
Butterfly weed Asclepias tuberosa first bloom 1216  
Mimosa Albizia julibrissin full bloom 1330  
Beebalm Monarda spp first bloom 1380  
Goldenraintree Koelreuteria paniculata first bloom 1393  
Satin blue Rose-of-Sharon Hibiscus syriacus 'Satin Blue' first bloom 1492  
Swamp milkweed Asclepias incarnata first bloom 1510  
Green June beetle Cotinus nitida adult emergence 1539 F
Pine needle scale Chionaspis pinifoliae egg hatch/crawler (2nd gen) 1561 F
Goldenraintree Koelreuteria paniculata full bloom 1597  
White prunicola scale Psedaulacaspis prunicola egg hatch/crawler (2nd gen) 1637

F

Satin blue Rose-of-Sharon Hibiscus syriacus 'Satin Blue' full bloom 1742  
Obscure scale Melanaspis obscura egg hatch/crawler 1774 F
Orangestriped oakworm Anisota senatoria egg hatch/early instar 1917 F, A
Magnolia scale Neolecanium cornuparvum crawler 1938* A
Fall webworm Hyphantria cunea egg hatch/early instar (2nd gen) 1962  
Maskell scale Lepidosaphes pallida egg hatch/crawler (2nd gen) 2035  
Regent pagodatree Styphnolobrium japonicum first bloom 2111  
Euonymus scale Unaspis euonymi egg hatch/crawler (2nd gen) 2235  
Crape myrtle 'Natchez' Lagerstroemia x 'Natchez' first bloom 2251  
Mimosa webworm Homadaula anisocentra larva,early instar (2nd gen) 2260  
Regent pagodatree Styphnolobrium japonicum full bloom 2330  
Crimsoneyed rosemallow Hibiscus moscheutos first bloom 2464  
Hollow Joe pye weed Eutrochium fistulosum first bloom 2494  
Japanese maple scale Lopholeucaspis japonica egg hatch/crawler (2nd gen) 2508 F
Crape myrtle 'Natchez' Lagerstroemia x 'Natchez' full bloom 2617  
Crimsoneyed rosemallow Hibiscus moscheutos full bloom 2704  
Seven-son flower Heptacodium miconioides first bloom 2770  
Fern scale Pinnaspis aspidistrae egg hatch/crawler (2nd gen) 2813  
Seven-son flower Heptacodium miconioides full bloom 3072  
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 3519 A

* Source: Average Degree Days (DD) Ohio State University (OSU) research data
** Source:  Average DD using UMD research data combined with OSU research data