In 1988, Warren Johnson of Cornell University produced one of the most comprehensive lists of insects and mites that attack trees and shrubs and associated degree-day (DD) activity periods. These DD periods were not developed using rigorous observations and model development. They were developed by taking yearly notes of insect and mite activities. These notes were then compared to DD charts for those same years and a range of DDs (base 50°F) were recorded.
The original list of insects and mites has been reduced to those which are of importance to Ohio operations.
Table 1. Common names, scientific names of insects and degree days (DD50) affecting ornamental plants.
| Growing Degree Days | |||||||
| Common Name | Scientific Name | min1 | max1 | min2 | max2 | min3 | max3 |
| Aphids | 7 | 120 | 135 | 250 | |||
| Elm bark beetles | Scolytus sp., Hylurgopinus sp. | 7 | 120 | ||||
| Elongate hemlock scale | Fiorinia externa | 7 | 120 | 360 | 700 | 2515 | 2625 |
| European red mite | Panonychus ulmi | 7 | 58 | 240 | 810 | ||
| Golden oak scale | Asterolecanium variolosum | 7 | 121 | 802 | 1266 | ||
| Kermes oak scales | Allokermes sp. | 7 | 91 | 298 | 912 | ||
| Oak leaftier | Croesia semipurpurana | 7 | 35 | ||||
| Oystershell scale | Lepidosaphes ulmi | 7 | 91 | 363 | 707 | ||
| Spruce spider mite | Oligonychus ununguis | 7 | 121 | 192 | 363 | 2375 | 2806 |
| Taxus mealybug | Dysmicoccus wistariae | 7 | 91 | 246 | 618 | ||
| White pine aphid | Cinara strobi | 7 | 121 | 121 | 246 | 1917 | 2271 |
| Tuliptree scale | Toumeyella liriodendri | 12 | 121 | 2032 | 2629 | ||
| Cooley spruce gall adelgid | Adelges cooleyi-on spruce | 22 | 92 | 1500 | 1775 | ||
| Juniper scale | Carulaspis juniperi | 22 | 148 | 707 | 1260 | ||
| Magnolia scale | Neolecanium cornuparvum | 22 | 91 | 246 | 448 | 2155 | 2800 |
| Pine bark adelgid | Pineus strobi | 22 | 58 | 58 | 618 | ||
| Spruce bud scale | Physokermes piceae | 22 | 121 | 912 | 1388 | ||
| European pine shoot moth | Rhyacionia buoliana | 34 | 121 | ||||
| Euonymus scale | Unaspis euonymi | 35 | 120 | 533 | 820 | ||
| European fruit lecanium | Parthenolecanium corni | 35 | 145 | 1266 | 1645 | ||
| Fletcher scale | Parthenolecanium fletcheri | 35 | 148 | 1029 | 1388 | 2515 | 2800 |
| Hemlock scale | Abgrallaspis ithacae | 35 | 121 | 1388 | 2154 | ||
| Balsam twig aphid | Mindarus abietinus | 58 | 120 | ||||
| Honeylocust plant bug | Diaphnocoris chlorionis | 58 | 246 | ||||
| Maple bladdergall mite | Vasates quadripedes | 58 | 148 | 98 | 155 | ||
| Pine tortoise scale | Toumeyella parvicornis | 58 | 148 | 618 | 1050 | ||
| Eastern tent caterpillar | Malacosoma americanum | 90 | 190 | ||||
| Gypsy moth | Lymantria dispar | 90 | 448 | ||||
| Cooley spruce gall adelgid | Adelges cooleyi - on fir | 120 | 190 | 1500 | 1775 | ||
| Nantucket pine tip moth | Rhyacionia frustrana | 121 | 448 | 1514 | 1917 | ||
| Woolly larch adelgid | Adelges laricis | 121 | 192 | ||||
| Zimmerman pine moth | Dioryctria zimmermani | 121 | 246 | 912 | 1917 | 1917 | 2154 |
| Black vine weevil | Otiorhynchus sulcatus | 148 | 400 | ||||
| Cankerworms (inch worms) | 148 | 290 | |||||
| Dogwood borer | Synanthedon scituia | 148 | 700 | ||||
| Lilac borer | Podosesia syringae | 148 | 299 | ||||
| Birch leafminer | Fenusa pusilla | 190 | 290 | 530 | 700 | ||
| Holly leafminer | Phytomyza ilicis | 192 | 290 | 246 | 448 | ||
| Honeylocust pod gall midge | Dasineura gleditschiae | 192 | 229 | ||||
| Imported willow leaf beetle | Plagiodera versicolora | 192 | 448 | ||||
| Larch sawfly | Pristophora erichsonii | 192 | 299 | ||||
| Linden looper | Erannis tiliaris | 192 | 363 | ||||
| Native holly leafminer | Phytomyza ilicicola | 192 | 298 | 1029 | 1266 | ||
| Rhododendron borer | Synanthedon rhododendri | 192 | 298 | 533 | 707 | ||
| Rhododendron gall midge | Clinodiplosis rhododendri | 192 | 363 | ||||
| Lace bugs | Corythuca sp. | 239 | 363 | 1266 | 1544 | ||
| Arborvitae leafminers | Argyresthia sp. | 245 | 360 | 533 | 700 | 1700 | 2100 |
| Boxwood psyllid | Psylia buxi | 290 | 440 | ||||
| Locust leafminer | Odontota dorsalis | 298 | 533 | 1029 | 1388 | ||
| Pine needle scale | Chionaspis pinifoliae | 298 | 448 | 1388 | 1917 | ||
| Elm leaf beetle | Xanthogaleruca luteola | 363 | 912 | ||||
| Elm leaf miner | Fenusa ulmi | 363 | 530 | ||||
| Larch casebearer | Coleophora laricella | 363 | 618 | 2375 | 2805 | ||
| Twospotted spider mite | Tetranychus urticae | 363 | 618 | ||||
| Bronze birch borer | Agrilus anxius | 440 | 800 | ||||
| Azalea whitefly | Pealius azaleae | 448 | 700 | 1250 | 1500 | 2032 | 2150 |
| Boxwood leafminer | Monarthropalpus buxi | 448 | 700 | ||||
| Lace bugs | Stephanitis sp. | 448 | 618 | 802 | 1029 | ||
| Mountain ash sawfly | Pristiphora geniculata | 448 | 707 | ||||
| Oak skeletonizer | Bucculatrix ainsliella | 448 | 707 | 1798 | 2155 | ||
| Spruce needle miner | Endothenia albolineane | 448 | 802 | ||||
| Greenstriped mapleworm | Dryocampa rubicunda | 533 | 1645 | ||||
| Bagworm | Thyridopteryx ephemeraeformis | 600 | 900 | ||||
| Cottony maple scale | Pulvinaria innumerabilis | 802 | 1265 | ||||
| Oak spider mite | Oligonychus bicolor | 802 | 1266 | ||||
| Roundheaded apple tree borer | Saperda candida | 802 | 1029 | 1514 | 1798 | ||
| Honeylocust mite | Eotetranychus multidigituli | 912 | 1514 | ||||
| European elm scale | Gossyparia spuria | 1029 | 1388 | ||||
| Japanese beetle | Popillia japonica | 1029 | 2154 | ||||
| Walnut caterpillar | Datana integerrima | 1029 | 1514 | ||||
| Dogwood sawfly | Macremphytus tarsatus | 1151 | 1500 | ||||
| Tuliptree aphid | Macrosiphum liriodendri | 1151 | 1514 | 1917 | 2033 | ||
| Fall webworm | Hyphantria cunea | 1266 | 1795 | ||||
| Maple trumpet skeletonizer | Epinotia aceriella | 1388 | 2032 | ||||
| Twobanded Japanese weevil | Callirhopalus bifasciatus | 1644 | 2271 | ||||
| Locust borer | Megacyllene robiniae | 2271 | 2805 | ||||
|
Growing Degree Days (GDD) = average cumulative degree days with a threshold of 50°F.
Min1-Max1, etc. = range of GDD during which pest is susceptible to control. If more than one range of numbers appear, multiple generations and/or control periods are expected. |
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