July Pest Scouting Nursery, Landscape, and Christmas Trees – Key borer and scale insect control timings

Pest Scouting – Please refer to these documents for a full listing of insects pests for your area corresponding to growing degree-days (GDDs). 

Quick look guides for July (Borers and Scales) and (All other) 

Contact if seeing insects at different times: twaller@njaes.rutgers.edu (or call the Cumberland County Extension Office – 856-451-2800)

The following key groups of pests will be active, vulnerable, or otherwise treatable during the next month throughout most of NJ. Here, scale insects and borers with key life stage events during the 1000-2500 GDD timeframe are discussed. Note there are many other insect pests present this time of year so please view the pest scouting guides above for your particular needs.

Projected GDD50 Accumulation as of July 13 2022 Note: Growing degree-day values utilize daily average air temperatures with a minimum temperature threshold (a.k.a. ‘base’) of 50F = GDD50 (max. temp. threshold set at 95F). These values are accumulated from a biofix date, such as January or March 1st in the NE USA. Provided GDD50 are scouting ranges and should be truthed.
Region Location Station 13-Jul 1-Aug 1-Sep
South Upper Deerfield NJ50 1598 2115 2905
Central Howell / Freehold NJ10 1383 1871 2594
North High Point NJ59 1132 1541 2138
Forecast: NOAA NCEP Coupled Forecast System model version 2 (CFSv2) forecast system (3.5 months) (USPEST.ORG)

Refer to this post “Obtaining your local growing degree-days” for additional information 

BORER Insect Activity for 1000-2500 GDD (~ July)
Crop type Common Name Scientific Name GDD Min (50F) GDD Max (95F) Reference Developmental / Target Stage
Many Roundheaded appletree borer Saperda candida 802 1129 RU Adults
Ash Emerald ash borer Agrilus planipennis 1000 1200 4 Peak adult activity
Many Roundheaded apple tree borer Saperda candida 1514 1798 5 Typical treatment window
Conifer Nantucket tip moth Rhyacionia frustrana 1514 1917 RU Adults 2nd generation
Maple Sugar maple borer Glycobius speciosus 2032 2375 5 Typical treatment window
Locust Locust borer Magacyllene robiniae 2271 2805 5 Typical treatment window
Poplar and Willow Poplar and willow borer Crytorhynchus lapathi 2271 2806 5 Typical treatment window

Click here – “Identifying Clearwing Moth Borers in Pheromone Traps” or “Differentiating the Common Wood Borers of Ash Trees”

SCALE Insect Activity for 1000 – 2500 GDD (~ July)
Crop type Common Name Scientific Name GDD Min (50F) GDD Max (95F) Reference Developmental / Target Stage
Conifer Cryptomeria scale Aspidiotus cryptomeriae 600 800 3 First crawler emergence
Many White prunicola scale Psedaulacaspis prunicola 707 1151 RU Crawlers (1st generation)
Conifer Juniper scale Carulaspis juniperi 707 1260 RU Crawlers (1st generation)
Many Calico scale Eulecanium cerasorum 714 6 Crawlers (1st generation)
Conifer Striped pine scale Toumeyella pini 750 800 4 Egg hatch
Oak, hickory, birch, many Oak leacanium scale Parthenolecanium quercifex 789 6 Crawlers (1st generation)
Acer Cottony maple leaf scale Pulvinaria acericola 802 1265 5 Crawlers (1st generation)
Many, shadetrees Cottony maple scale Pulvinaria innumerabilis 802 1265 RU Crawlers (1st generation) – control target
Oaks Golden oak scale Asterolecanium variolosum 802 1266 5 Egg hatch
Maples Japanese maple scale Lopholeucaspis japonica 829 6 Crawlers (1st generation)
Elm European elm scale Gossyparia spuria 831 1388 6,2 Crawlers (1st generation)
Shade trees European fruit lecanium scale Parthenolecanium corni 932 1645 6,RU Crawlers  – control target
Conifer Pine tortoise scale Toumeyella parvicornis 1000 1200 4 Egg hatch ends, last of crawlers
Yew, many conifers Fletcher Scale (Yew) Parthenolecanium fletcheri 1029 1388 RU Crawlers (1st generation) – control target
Many Indian wax scale Ceroplastes ceriferus 1145 6 Crawlers (1st generation)
Euonymus Euonymus Scale Unaspis euonymil 1150 1388 5 2nd generation targeted treatments
Shade trees European fruit lecanium scale Parthenolecanium corni 1266 1645 5 Crawlers
Conifer Pine Needle Scale Chionaspis pinifoliae 1290 1917 3 Crawlers emerge (2nd generation) – control target
Conifer Hemlock scale Abgrallaspis ithacae 1388 2154 5 Typical treatment window
Malus, Prunus, many Peachtree borer Synanthedon sp. 1500 1800 RU Larvae Treatment
Many White prunicola scale Pseudaulacaspis prunicola 1637 6 Egg hatch / crawler (2nd generation)
Euonymus Euonymus Scale Unaspis euonymil 1700 RU Continued 2nd generation treatments
Conifer Cryptomeria scale Aspidiotus cryptomeriae 1750 2130 RU, 4 Crawlers emerge (2nd generation)
Many Obscure scale Melanaspis obscura 1774 6 Egg hatch / crawler
Conifer Maskell scale lepidosaphes pallia 2035 6 Egg hatch / crawler (2nd generation)
Mainly Tulip Tulip tree scale Toumeyella liriodendri 2037 2629 RU Crawlers (1st generation)
Mainly Magnolia Magnolia scale Neolecanium cornuparvum 2155 2800 RU Crawlers (1st generation)
Maple Japanese maple scale Lopholeucaspis japonica 2508 6 Egg hatch / crawler (2nd generation)
Conifer Elongate hemlock scale Fiorinia externa 2515 2625 RU Typical treatment window – fall activity
Yew, many conifers Fletcher Scale (Yew) Parthenolecanium fletcheri 2515 2800 RU Fall control of overwintering stage

Other Insect Activity for 1000 – 2500 GDD (~ July)
Crop type Common Name Scientific Name GDD Min (50F) GDD Max (95F) Reference Developmental / Target Stage
Many Redheaded flea beetle Systena frontalis 1028 1570 Unv. Del 2nd generation of un-hatched eggs
Locust Locust leafminer Odontota dorsalis 1029 1388 RU Adults
Juglandaceae Walnut Caterpillar Datana integerrima 1029 1514 2 Larvae Treatment
Turf Bluegrass billbug Sphenophorus parvulus 1094 1217 RU Larvae (40%)
Many Oriental Beetle Anomala orientalis 1147 6 Adult emergence
Dogwood Dogwood sawfly Macremphytus tarsatus 1151 1500 RU Larvae Treatment
Tulip Tuliptree aphid Illinoia liriodendri 1151 1514 RU Nymphs / adults
Boxwood Boxwood leafminer Monoarthropalpus flavus 1200 1400 5 Larvae Treatment
Conifer Northern pine weevil Pissodes nemorensis 1200 1400 4 2nd generation adults active
Conifer Pales weevil Hylobius pales 1200 1400 4 Adults 2nd generation
Conifer Pine root collar weevil Hylobius radicis 1200 1400 4 2nd generation adults active
Conifer White pine weevil Pissodes strobi 1200 1400 4 2nd generation adults active
Rhododendron Azalea whitefly Pealius azaleae 1250 1500 5 Adults/nymphs (2nd generation)
Turf Bluegrass sod webworm Parapediasia teterrella 1250 1920 RU Larvae
Privet Privet rust mite Aculus ligustri 1266 1515 5 Second typical treatment window
Many Lacebugs ( on hawthorn) Corythucha cydoniae 1266 1544 RU Nymphs / adults
Many Leafhoppers Species within Cicadellidae 1266 1544 RU Nymphs / adults
Birch Birch Skeletonizer Bucculatrix canadensisella 1266 1580 5 Typical treatment window
Many Fall webworm Hyphantria cunea 1266 1795 2 Caterpillars present – larvae treatment
Many Two spotted spider mite Tetranychus urticae 1300 2000 RU Nymphs / adults
Turf N. Masked chafer Cyclocephala borealis 1377 1579 RU Adults (90%)
Lilac Lilac leafminer Caloptilia syringella 1388 1644 5 Typical treatment window
Conifer Cooley spruce gall adelgid Adelges cooleyi 1500 1775 RU Adults/nymphs (Douglas Fir)
Many Redheaded flea beetle Systena frontalis 1570 1860 Unv. Del 2nd generation egg hatch
Many Japanese beetle Popillia japonica 1590 1925 RU Adults (90%)
Conifer Rust-mites Nalepella and Setoptus spp. 1644 2030 RU Nymphs / adults
Many Two-banded Japanese weevil Pseudocneorhinus bifasciatus 1644 2271 RU Adults
Willow Willow twig aphids Lachnus spp. 1644 2271 5 Typical treatment window
Conifer Juniper webworm Dichomeris marginella 1645 1917 RU Larvae Treatment
Oaks Oak skeletonizer Bucculatrix ainsliella 1798 2155 RU Larvae
Mimosa, Honeylocust Mimosa webworm Homadaula anisocentra 1800 2100 RU Larvae (2nd generation)
Conifer Arborvitae leafminer Argyresthia thuiella 1800 2200 RU Larvae Treatment (3rd generation)
Conifer Cooley spruce gall adelgid Adelges cooleyi 1850 1950 RU Galls open (Spruce)
Turf Hairy chinch bug Blissus leucopterus 1903 2160 RU Second generation- 50%- 2nd instars
Tulip Tuliptree aphid Illinoia liriodendri 1917 2033 RU Nymphs
Conifer Zimmerman pine moth Dioryctria zimmermani 1917 2154 5 Treatment window (adult flight-1700 GDD)
Mainly Oaks Orangestriped oakworm Anisota senatoria 1917 6 Egg hatch – early instars
Conifer White pine aphid Cinara strobi 1991 2271 RU Adults
Rhododendron Azalea whitefly Pealius azaleae 2032 2150 5 Adults/nymphs (3rd generation)
Conifer Spruce spider mite Oligonychus ununguis 2375 2806 5 Typical treatment window
Many Southern red mite Oligonychus ilicis 2500 2700 5 Typical treatment window

Click here – “Some Key Armored Scales & Crawler Emergence” or “Some Key Soft Scale Pests in the Landscape”

References: 

NOTE: Daily GDD50 =(Max (95F) + Min temp. (50F)) / 2 – base/min temp. (50F) Click here for USPEST.org or NEWA
RU Rutgers Cooperative Extension – Landscape IPM Notes
2 http://ccetompkins.org/resources/using-growing-degree-days-for-insect-management
3 https://extension.psu.edu/ipm-basics-for-christmas-trees#section-2
4 https://www.canr.msu.edu/ipm/agriculture/christmas_trees/gdd_of_conifer_insects
5 https://www.agriculture.nh.gov/publications-forms/documents/landscape-pests.pdf
6 https://extension.umd.edu/ipm/pest-predictive-calendar-landscapenursery
7 https://www.canr.msu.edu/ipm/agriculture/christmas_trees/gdd_of_landscape_insects
Unv. Del. Coorespondance with Dr. Kunkel (University of Delaware)-evolving GDD ranges