Pest-Predictive Calendar

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	first adult 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	larva/early instar	230	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
Spiny ash sawfly	Eupareophora parca	larva, early instar	358	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	A
Basswood lace bug	Gargaphia tiliae	first 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 (Diaphnocoris) chlorionis	egg hatch, early instar	433	A
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)	486²	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	F
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
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
San Jose scale	Quadraspidiotus perniciosus	egg hatch/crawler (1st gen)	723	A
Crapemyrtle bark scale	Acanthococcus lagerstroemiae	egg hatch (1st gen)	724	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	first adult activity	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	A, A
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	F
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