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	GDD	Links
Corneliancherry dogwood	Cornus mas	first bloom	22
Red maple	Acer rubrum	first bloom	34
Border forsythia	Forsythia x intermedia	first bloom	35
Euonymus leaf-notcher caterpillar	Pryeria sinica	egg hatch	37
Red maple	Acer rubrum	full bloom	42
Callery pear	Pyrus calleryana	first bloom	50
Eastern tent caterpillar	Malacosoma americanum	egg hatch	51
Purple deadnettle	Lamium purpureum	first bloom	52
Border forsythia	Forsythia x intermedia	full bloom	53
Saucer magnolia	Magnolia x soulangeana	first bloom	59
Star magnolia	Magnolia stellata	first bloom	89
Flowering quince	Chaenomeles speciosa	first bloom	103
Bridal wreath spirea	Spirea x vanhouttei	first bloom	104
Callery pear	Pyrus calleryana	full bloom	105
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
Double weeping higan cherry	Prunus shubhirtella 'Pendula Plena Rosa'	first bloom	142
Eastern redbud	Cercis candensis	full bloom	156
Fernald’s shadbush	Amelanchier fernaldii	full bloom	163
Nantucket serviceberry	Amelanchier nantucketensis	full bloom	171
Spiny witchhazel gall aphid	Hamamelistes spinosus	adult/nymph	171
Serviceberry 'Autumn Brilliance'	Amelanchier x grandiflora	first bloom	179
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
Serviceberry 'Autumn Brilliance'	Amelanchier x grandiflora	full bloom	235
Boxwood leafminer	Monarthropalpusi flavus	adult emergence	249
Crabapple 'Adirondack'	Malus 'Adirondack'	first bloom	260
Dwarf azalea	Rhododendron atlanticum	first bloom	260
Mayapple	Podophyllum peltatum	first bloom	264
Spruce spider mite	Oligonychus ununguis	adult/nymph	276
Dogwood 'Appalachian Spring'	Cornus florida 'Appalachian Spring'	first bloom	281
Pine needle scale	Chionaspis pinifoliae	egg hatch (1st gen)	283
Hemlock woolly adelgid	Adelges tsugae	egg hatch (1st gen)	300
Sheep laurel	Kalmia angustifolia 'Royal Dwarf'	first bloom	314
Spirea aphid	Aphis spiraecola	adult/nymph	326
Lilac borer	Podosesia syringae	adult emergence	350
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
Crabapple 'Adirondack'	Malus 'Adirondack'	full bloom	379
Black locust	Robinia pseudoacacia	full bloom	386
Red horsechestnut	Aesculus x carnea 'Ft. McNair'	first bloom	389
Emerald ash borer	Agrilus planipennis	adult emergence	421
Blue false indigo	Baptisia australis 'Purple Smoke'	first bloom	431
Black locust	Robinia pseudoacacia	full bloom	447
Basswood lace bug	Gargaphia tiliae	adult/nymph	462
Lesser peachtree borer	Synanthedon pictipes	adult emergence (1st gen)	468
Maskell scale	Lepidosaphes pallida	egg hatch (1st gen)	470
Virginia spiderwort	Tradescantia virginiana	first bloom	494
Gypsy moth	Lymantria dispar	egg hatch	507
Red horsechestnut	Aesculus x carnea 'Ft. McNair'	full bloom	511
Hawthron 'Winter King'	Crataegus viridis 'Winter King'	full bloom	515
Euonymus scale	Unaspis euonymi	egg hatch (1st gen)	522
American smoketree	Cotinus obovatus	full bloom	575
Common ninebark	Physocarpus opulifolius ‘Luteus’	full bloom	583
Yellow flag iris (Maryland Tier 1 invasive plant)	Iris pseudacorus	first bloom	587
Clematis 'Westerplatte'	Clematis ‘Westerplatte’	full bloom	589
White prunicola scale	Psedaulacaspis prunicola	egg hatch (1st gen)	594
American yellowwood	Cladrastis kentukea	first bloom	600
Bagworm	Thyridopteryx ephemeraeformis	egg hatch	602
American yellowwood	Cladrastis kentukea	full bloom	627
Potato leafhopper	Empoasca fabae	adult arrival	659
Virginia spiderwort	Tradescantia virginiana	full bloom	692
Juniper scale	Carulaspis juniperi	egg hatch	694
Oak leacanium scale	Parthenolecanium quercifex	egg hatch	773
Japanese maple scale	Lopholeucaspis japonica	egg hatch (1st gen)	829
Cottony camellia/taxus scale	Pulvinaria floccifera	egg hatch	856
Smoketree	Cotinus coggygria	full bloom	866
Calico scale	Eulecanium cerasorum	egg hatch	887
Japanese stewartia	Stewartia pseudocamelia	first bloom	908
Smooth witherod/Possumhaw viburnum	Viburnum nudum ‘Winterthur’	full bloom	1002
Mimosa Webworm	Homadaula anisocentra	egg hatch (1st gen)	1002
Japanese stewartia	Stewartia pseudocamelia	full bloom	1027
Japanese beetle	Popillia japonica	adult emergence	1056
Fletcher scale	Parthenolecanium fletcheri	egg hatch	1105
Bottlebrush buckeye	Aesculus parviflora	first bloom	1137
Indian wax scale	Ceraplastes ceriferus	egg hatch	1145
Cryptomeria scale	Aspidiotus cryptomeriae	egg hatch (1st gen)	1190
Cottony maple scale	Pulvinaria innumerabilis	egg hatch	1194
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
Fall webworm	Hyphantria cunea	egg hatch (1st gen)	1530
Pine needle scale	Chionaspis pinifoliae	egg hatch (2nd gen)	1537
Green June beetle	Cotinus nitida	adult emergence	1539
Goldenraintree	Koelreuteria paniculata	full bloom	1597
White prunicola scale	Psedaulacaspis prunicola	egg hatch (2nd gen)	1637
Satin blue Rose-of-Sharon	Hibiscus syriacus 'Satin Blue'	full bloom	1742
Euonymus scale	Unaspis euonymi	egg hatch (2nd gen)	1770
Orangestriped oakworm	Anisota senatoria	egg hatch (early instar)	1969
Maskell scale	Lepidosaphes pallida	egg hatch (2nd gen)	2035
Regent pagodatree	Styphnolobrium japonicum	first bloom	2204
Regent pagodatree	Styphnolobrium japonicum	full bloom	2436
Crimsoneyed rosemallow	Hibiscus moscheutos	first bloom	2464
Hollow joe pye weed	Eutrochium fistulosum	first bloom	2494
Japanese maple scale	Lopholeucaspis japonica	egg hatch (2nd gen)	2508
Crimsoneyed rosemallow	Hibiscus moscheutos	full bloom	2704
Seven-son flower	Heptacodium miconioides	first bloom	2770
Fall webworm	Hyphantria cunea	egg hatch (2nd gen)	2793
Seven-son flower	Heptacodium miconioides	full bloom	3072
White prunicola scale	Psedaulacaspis prunicola	egg hatch (3rd gen)	3270
Banded ash clearwing borer	Podosesia aureocincta	adult emergence	3357
Tuliptree scale	Toumeyella liriodendri	egg hatch	3519