Please note: The Rutgers Nursery and Green Industry Working Group is working to deliver regular pest and disease updates throughout the season. These will be in addition to important alerts, critical topics, and pesticide credit opportunities. This tool is made for you, the commercial agriculture business, so please let us know if there are particular topics you would like to see included in the regular update.
Email: twaller@njaes.rutgers.edu Phone: 856-451-2800 Ext. 1.
Insect Pests
| Projected GDD50 accumulation as of 4/25/2023 (these change throughout the season!) | ||||||
| Region | Location | 25-Apr | 1-May | 1-Jun | 1-Jul | 1-Aug |
| Southern | Upper Deerfield (NJ50) | 251 | 281 | 682 | 1370 | 2218 |
| Central | Howell / Freehold (NJ10) | 188 | 207 | 537 | 1160 | 1957 |
| Northern | High Point (NJ59) | 142 | 143 | 371 | 864 | 1507 |
| Forecast: 7-month NMME based seasonal climate forecast (USPEST.ORG) | ||||||
Please download and print the Rutgers Nursery and Landscape Pest Scouting Guide or Conifer and Christmas Tree Pest Scouting Guide and refer to this post “Obtaining your local growing degree-days (GDD)” for additional information. (See pest scouting guides for complete list of references)
Please SHARE what you SEE!! If you see a pest, disease, otherwise interesting or troublesome issue please report it to the Working Group by following the QR Code on the front of the Pest Scouting Guides or by filling out this reporting form.
Please continue reading for much more detailed and important information!
PESTS ON THE RADAR
Borers: Many clearwing borers are active now! Borers attack stressed plants. If you recently dug then heeled-in trees, transplanted seedlings, or otherwise seriously stressed a tree, please consider taking immediate action to protect them from both adult flights (contact trunk sprays) and future infestations (systemics).
| Group | Common Name | Scientific Name | GDD Min (50F) | GDD Max (95F) | Ref. | Developmental / Target Stage / Notes | Favored Host Plants |
| Borer – Caterpillar | Eastern pine shoot borer | Eucosma gloriola | 75 | 200 | 4 | 1st adults active | Conifer |
| Borer – Clearwing moth | Lilac / Ash Borer | Podosesia syringae | 148 | 299 | 2 | Adult flight | Lilac, ash, privet, many |
| Borer – Clearwing moth | Dogwood Borer | Synanthedon scitula | 148 | 700 | 2 | Adult activity | Dogwood, many |
| Borer – Clearwing moth | Rhododendron borer | Synanthedon rhododendri | 192 | 298 | 2 | Typical treatment window | Rhododendron |
| Borer – Clearwing moth | Lilac / Ash Borer | Podosesia syringae | 200 | 299 | 1 | Adults – 1st Treatment | Lilac, ash, privet, many |
| Borer – Caterpillar | American plum borer | Euzophera semifuneralis | 245 | 440 | 5 | Adult flight, egg laying | Prunus |
| Borer – Clearwing moth | Lesser peach tree borer | Synanthedon pictipes | 350 | 375 | 4 | Adult flight, egg laying | Malus, Prunus, many |
| Borer – Clearwing moth | Dogwood borer | Synanthedon scitula | 350 | 850 | 4 | adults, eggs, caterpillars | Dogwood, apple, pecan, elm, hickory, willow |
If borer insects are a common problem for your operation there are specific degree-day models made for Bronze birch borer and Emerald ash borer. You can set up these emailed alerts through the USPEST – PUSH Alerts for a multitude of pests and diseases. Contact twaller@njaes.rutgers.edu for assistance.
Based on these specific USPEST.org models:
- Bronze birch borer – Egg hatch -10% adult flight will be 5/1-5/13 in Southern NJ.
- Emerald ash borer – Egg hatch -10% adult flight will be 5/16 -5/24 in Southern NJ.
- More information on Clearwing Moth Borers in Pheromone Traps and Differentiating the Common Wood Borers of Ash Trees found here.
Scale insects: Start scouting for overwintering populations and following GDD to determine the best time to target crawlers.
| Group | Common Name | Scientific Name | GDD Min (50F) | GDD Max (95F) | Ref. | Developmental / Target Stage / Notes | Favored Host Plants |
| Scale | Pine Needle Scale | Chionaspis pinifoliae | 298 | 448 | 1 | Crawlers (1st generation) – control target | Conifer |
| Scale | Kermes oak scale | Allokermes spp. | 298 | 912 | 5 | Typical treatment window | Oaks |
| Scale | Elongate Hemlock Scale | Fiorinia externa | 360 | 700 | 1 | Crawlers (1st generation) | Conifer |
| Scale | Oystershell Scale | Lepidosaphes ulmi | 363 | 707 | 1 | Crawlers | Many |
Please visit these posts regarding soft scales and armored scales in the nursery and landscape.
Other insects:
- Redheaded flea beetle hatch now through the next few weeks in NJ. Please refer to this RHFB Chart to investigate possible control options at this time of the season. Please refer to this RHFB materials and timing chart.
- SLF has begun to hatch in Southern NJ and will soon be hatching throughout the state. Spotted lanternfly Life Stages, Where to Look, and Homeowner Management graphic from forth coming factsheet.
- Multiple caterpillars will be hatching now or very soon.
| Group | Common Name | Scientific Name | GDD Min (50F) | GDD Max (95F) | Ref. | Developmental / Target Stage / Notes | Favored Host Plants |
| Caterpillar | Eastern tent caterpillar | Malacosoma americanum | 90 | 190 | 2 | Larvae treatment before tents apparent (near 150-GDD50) | Malus, Prunus, many |
| Caterpillar | Spongy moth (formerly Gypsy) | Lymantria dispar | 90 | 448 | 1 | Larvae treatment (early instars) | Many |
| Lacebug | Azalea lace bug | Stephanitis pyrioides | 118 | 372 | 1 | Nymphs (1st generation) | Azalea |
| Leafminer / Midge / Fly | Birch leafminer | Fenusa pusilla | 190 | 290 | 1 | Larvae (1st generation) | Birch |
| Leafminer / Midge / Fly | Honeylocust pod gall midge | Dasineura gleditchiae | 192 | 229 | 1 | Larvae | Honeylocust |
| Leafminer / Midge / Fly | Rhododendron gall midge | Clinodiplosis rhododendri | 192 | 363 | 1 | Larvae | Rhododendron |
| Cicadellidae | Spotted Lantern Fly | Lycorma delicatula | 225 | 1100 | 9 | 1st-4th Instar (nymphs) – control target | Many |
| Sawfly – Wasp | Roseslug sawfly | Endelomyia aethiops | 230 | – | 6 | Egg hatch / early instars | Wild and cultivated roses |
| Beetle | Redheaded flea beetle | Systena frontalis | 242 | 600 | 8 | First control target – egg hatch / larval activity | Many |
| Leafminer / Midge / Fly | Arborvitae leafminer | Argyresthia thuiella | 245 | 360 | 1 | Larvae Treatments (1st generation) | Conifer |
| Mites | Boxwood mites | Eurytetranychus buxi | 245 | 600 | 1 | All Stages | Boxwood |
| Leafminer / Midge / Fly | Holly leafminer | Phytomyza ilicis | 246 | 448 | 1 | Larvae Treatment | Holly |
| Leafminer / Midge / Fly | Boxwood leafminer | Monarthropalpusi flavus | 249 | – | 6 | Adult emergence | Boxwood |
| Adelgid | Hemlock woolly adelgid | Adelges tsugae | 350 | 350 | 1 | Eggs and 50% hatch | Conifer |
Click here – “Landscape Notes April 2023”
DISEASES ON THE RADAR
Boxwood Blight (BWB)
- If BWB is important to your business – Use the USPEST – PUSH Alerts – (click here) – to setup weekly email alerts. Create an account, watch the tutorial, and then set up your subscriptions. You select which locations (as many as you like), days you want to receive emails (pick Sunday/Monday), and what you would like to receive alerts about (BWB and a variety of other pests and diseases). Rutgers is not directly affiliated, however this is an incredible tool.
- The last updated Boxwood Blight Alert – use as a reference
Phytophthora and Pythium
- We will be posting an much more indepth post very soon, however please review this Oomycete (Phytophthora, Pythium, Phytopythium, Downy mildews) materials and considerations.
Leaf spots / Foliar damages
- Many plants are beginning to leaf out and protective fungicide applications may be warranted. In seasons past we have observed what appeared to be RHFB or other chewing insect damage only to realize this was caused by fungal infections initiated during this time of season. Please refer to labels and contact your local agent to determine the best course of action for specific crops.
Please SHARE what you SEE!! If you see a pest, disease, otherwise interesting or troublesome issue please report it to the Working Group by following the QR Code on the front of the Pest Scouting Guides or by filling out this reporting form.
