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, 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 |
| 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 |
| 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 | A, F |
| Koreanspice viburnum | Viburnum carlesii | first bloom | 117 | F |
| 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 |
| Boxwood spider mite | Eurytetranchus buxi | egg hatch | 141 | |
| 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 | 165² | |
| 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 | 184² | P |
| Double weeping higan cherry | Prunus subhirtella 'Pendula Plena Rosa' | full bloom | 195 | |
| Tea scale | Fiorinia theae | egg hatch/crawler (1st gen) | 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 | 210¹ | 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 | 215¹ | A |
| Elm leafminer | Fenusa ulmi | adult emergence | 219¹ | A |
| Roseslug sawfly | Endelomyia aethiops | egg hatch/early instar | 230 | A |
| Honeylocust plant bug | Diaphnocoris chlorionis | egg hatch | 230¹ | |
| Elongate hemlock scale | Fiorinia externa | egg hatch/ crawler (1st gen) | 232 | |
| 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 |
| Spotted lanternfly | Lycorma delicatula | egg hatch | 270³ | |
| 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 | 292² | |
| 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 | 308¹ | A |
| Eastern spruce gall adelgid | Adelges abietis | egg hatch | 308¹ | 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 | 375¹ | 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 | |
| Honeylocust plant bug | Blepharidopterus chlorionis | egg hatch, early instar | 433 | |
| Fourlined plant bug | Poecilocapsus lineatus | egg hatch/early instar | 435 | F, 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 | |
| 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 | |
| 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 (1st gen) | 522 | |
| Bronze birch borer | Agrilus anxius | adult emergence | 547¹ | A |
| 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 | |
| Potato leafhopper | Empoasca fabae | adult arrival | 603 | |
| Black vine weevil | Otiorhynchus sulcatus | adult emergence | 607¹ | F |
| American yellowwood | Cladrastis kentukea | full bloom | 627 | |
| Twospotted spider mite | Tetranychus urticae | egg hatch | 627¹ | F |
| Cottony camellia/Taxus scale | Pulvinaria floccifera | egg hatch/crawler | 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/crawler | 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 | 815¹ | F |
| Japanese maple scale | Lopholeucaspis japonica | egg hatch/crawler (1st gen) | 829 | F |
| Dogwood borer | Synanthedon scitula | adult emergence | 830¹ | |
| 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 | 892¹ | |
| 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 | 957¹ | F |
| Smooth witherod/Possumhaw viburnum | Viburnum nudum ‘Winterthur’ | full bloom | 1002 | |
| Hibiscus sawfly | Atomacera decepta | larva (early instar) | 1015 | |
| Japanese stewartia | Stewartia pseudocamellia | full bloom | 1027 | |
| Japanese beetle | Popillia japonica | adult emergence | 1056 | |
| Fletcher scale | Parthenolecanium fletcheri | egg hatch/crawler | 1105 | F, P |
| Spotted lanternfly | Lycorma delicatula | adult flight | 1112³ | |
| 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 | |
| Satin blue Rose-of-Sharon | Hibiscus syriacus 'Satin Blue' | full bloom | 1742 | |
| Obscure scale | Melanaspis obscura | egg hatch/crawler | 1774 | F |
| Spotted lanternfly | Lycorma delicatula | egg laying | 1825³ | |
| Orangestriped oakworm | Anisota senatoria | egg hatch/early instar | 1917 | F, A |
| Magnolia scale | Neolecanium cornuparvum | crawler | 1938¹ | 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 | 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