Please download or print the two resources of this post (click on them):
- 1-Page printable version Pest Scouting 0-25GDD and GDD forecasts
- Expanded pest table with clickable links pertaining to each pest’s biology, control considerations, and ID
How to use this pest scouting / growing degree-day (GDD50) information:
The information provided in the downloads give early season scouting ranges (in growing degree days) for specific insect pests. Additionally, forecasting predictions (GDD50 accumulation) per calendar date for multiple regions of New Jersey (S,N,C).
(Please note: we will be providing pest GDD ranges regularly throughout the season for our green industries)
Scouting Ranges (please download / print above resources):
- It is important to note that these GDD50 are not exact, rather provide a range of GDD and subsequent calendar dates that can be used to scout for, and treat for, insect pests.
- The pests listed here will be listed again in future scouting range announcements as they undergo further developmental life stages or are vulnerable to management options.
| Pest Scouting – Growing Degree-day Ranges | Starting (0-25 GDD50) | |||||
| Crop type | Common Name | Scientific Name | GDD Min (50F) | GDD Max (95F) | Reference | Developmental / Target Stage |
| Conifer | Conifer rust mites | Eriophyidae | 7 | 22 | 4 | Overwintering eggs hatch |
| Pomes, Stone fruit | European red mite | Panonychus ulmi | 7 | 58 | 2 | 1st adults active |
| Conifer | White pine weevil | Pissodes strobi | 7 | 58 | RU | Overwintering adults become active / prevent egg laying |
| Deciduous | Oystershell scale | Lepidosaphes ulmi | 7 | 91 | 2 | Spring control of overwintering stage |
| Deciduous, Yew | Cottony camellia / taxus scale | Pulvinaria floccifera | 7 | 91 | 5 | Spring control of overwintering stage |
| Many | Southern red mite | Oligonychus ilicis | 7 | 91 | 5 | Overwintering eggs hatch |
| Conifer | Taxus mealybug | Dysmicoccus wistariae | 7 | 91 | 2 | Spring control of overwintering stage |
| Oaks | Kermes oak scales | Kermes spp. | 7 | 91 | 2 | Spring control of overwintering stage |
| Conifer | Elongate hemlock scale | Fiorinia externa | 7 | 120 | 2 | Spring control of overwintering stage |
| Many | Aphids | Aphidoidea | 7 | 120 | 2 | Spring control of overwintering stage |
| Conifer | Spruce spider mite | Oligonychus ununguis | 7 | 121 | RU | Overwintering eggs hatch |
| Oaks | Golden oak scale | Asterolecanium variolosum | 7 | 121 | 5 | Spring control of overwintering stage |
| Conifer | Pales weevil | Hylobius pales | 7 | 121 | RU | Overwintering adults become active / prevent egg laying |
| Magnoliaceae | Tuliptree scale | Toumeyella liriodendri | 12 | 121 | 2 | Spring control of overwintering stage |
| Rhododendron, Azalea | Azalea lacebug | Stephanitis pyrioides | 18 | 372 | RU | Spring control of overwintering stage |
| White and Scotch Pine | White pine aphid | Cinara strobi | 22 | 91 | RU | Spring control of overwintering stage |
| Conifer | Pine bark adelgid | Pineus strobi | 22 | 58 | 2 | Spring control of overwintering stage |
| Magnoliaceae | Magnolia scale | Neolecanium cornuparvum | 22 | 91 | 2 | Spring control of overwintering stage |
| Conifer | Spruce bud scale | Physokermes piceae | 22 | 120 | 2 | Spring control of overwintering stage |
| Conifer | Juniper scale | Carulaspis juniperi | 22 | 148 | 2 | Spring control of overwintering stage |
| Conifer | Eastern spruce gall adelgid | Adelges abietis | 25 | 100 | 3 | spring control of overwintering stage |
| Conifer | Zimmerman pine moth | Dioryctria zimmermani | 25 | 100 | 3 | 1st larvae |
| Conifer | Cooley spruce gall adelgid | Adelges cooleyi | 25 | 120 | 3 | Spring control of overwintering stage |
| References | RU | Rutgers Cooperative Extension – IPM Notes | ||||
| 2 | http://ccetompkins.org/resources/using-growing-degree-days-for-insect-management | |||||
| 3 | https://www.canr.msu.edu/ipm/agriculture/christmas_trees/gdd_of_conifer_insects | |||||
| 4 | https://extension.psu.edu/ipm-basics-for-christmas-trees#section-2 | |||||
| 5 | https://www.agriculture.nh.gov/publications-forms/documents/landscape-pests.pdf | |||||
Forecasting (please download / print above resources):
- The forecasting can help you know what to scout for and when to have materials ready if treatment is required.
- In the printable resource; look at the date on the bottom of the graph and follow that to the GDD shown to get a better understanding of GDD accumulation at calendar dates. These models change constantly as they are reliant on weather patterns but are still extremely beneficial.
- Site specific GDD50 models, like those shown in the printable resource can be obtained at USPEST.ORG
- NEWA-Cornell also have great degree-day models and maps that are useful for regional and specific GDD information
- Please review Tim Waller’s previous post on utilizing growing degree-day calculators
| NJ – Location | Station Code | GDD-Today | GDD-3/19 (next Friday) |
| Upper Deerfield | NJ50 | 9 | 19 |
| Howell | NJ10 | 6 | 16 |
| High Point | NJ59 | 0 | 4 |
| *predicted |
Contact Tim Waller (twaller@njaes.rutgers.edu) for more information.
