April 23, 2021

Do you have Phytophthora concerns in your conifer nursery? We are looking for participants in a statewide study

Tim Waller (Cumberland Co.) and Bill Errickson (Monmouth Co.) of Rutgers Cooperative Extension are looking for 30 conifer producers to collaborate in a statewide Phytophthora sampling project, as part of a Specialty Crop Block Grant. This study will focus on identifying the species of Phytophthora limiting conifer production in New Jersey.

  • If your operation is selected, the agents will schedule one to three visits this growing season to collect samples from roots, bark, soil, irrigation systems, and will perform soil testing (Year 1).
  • During years 2 and 3, we will be performing chemical, biological, and cultural disease management trials in addition to conifer variety trials, at Rutgers-NJAES experiment stations. The aim is to generate local data – using local isolates in order to develop a more wholistic set of recommendations when targeting this disease in our NJ nurseries.

The agents also look forward to developing stronger relationships throughout New Jersey in the post-COVID19 era

 

This project is open to nurseries and Christmas tree farms producing conifers in NJ 

If you are interested in this project – please respond via this brief survey (click here) 

Please print and share this PDF survey with anyone not online (click here)

 

Please contact Tim Waller – twaller@njaes.rutgers.edu – (856-451-2800) – for more information

 

Filed Under: Commercial Ag Updates, Landscape, Nursery, & Turf, Nursery, Turf Tagged With: , , ,
April 15, 2021

Nursery and Landscape Pest Scouting Guide: 150-250 Growing Degree-days and Boxwood Blight Risk ( currently = low risk )

Nursery and Landscape Pest Scouting Guide 150-250 GDD50:

Please print or download these resources (click on them): 

Remember:

  • To determine your local growing degree-days, please review this post “Obtaining your local growing degree-day information”
  • The information provided in the downloads gives scouting GDD50 ranges (in growing degree days, base 50F) for specific insect pests harming nursery crop production and maintenance. 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.
  • This document supports scouting, it does not replace it. Keeping good notes on pest development will help dial in scouting and treatment efforts at your local level.
  • Forecasting predictions (GDD50 accumulation) for calendar dates of multiple regions of New Jersey (S,N,C) are provided.
  • If you need more information, OR you are regularly seeing specific pest development stages at growing degree-days different than those listed here, please contact Tim Waller at twaller@njaes.rutgers.edu

GREAT RESOURCE from Steve Rettke: “Landscape Pest Notes: Some Early Spring Insects/Mites”

 

Projected GDD50 accumulation as of 4/15/2021
Region Location 4/15/21 1-Apr 1-May 1-Jun 1-Jul Aug. 1st
Southern Upper Deerfield (NJ50) 141 75 230 636 1314 2156
Central Howell / Freehold (NJ10) 94 67 165 513 1135 1929
Northern High Point (NJ59) 50 21 56 268 721 1327
Forecast: NOAA NCEP Coupled Forecast System model version 2 (CFSv2) forecast system (3.5 months) (USPEST.ORG)

 

Pest Scouting – Growing Degree-day Ranges (150-250 GDD50)
CROP TYPE Common Name Scientific Name GDD Min (50F) GDD Max (95F) Reference Developmental / Target Stage
Malus, Prunus, many Eastern tent caterpillar Malacosoma americanum 90 190 2 Larvae treatment before tents apparent (near 150-GDD50)
Elm, Service berry Woolly elm aphid Eriosoma americana 121 246 2 (6) Control target
Conifer Hemlock woolly adelgid Adelges tsugae 150 150 RU Eggs and 10% hatch
Conifer Spruce spider mite Oligonychus ununguis 150 175 4 1st egg hatch
Conifer Spruce needleminer Endothenia albolineana 150 200 4 1st larvae active
Conifer Balsam gall midge Paradiplosis tumifex 150 300 4 Adults laying eggs
Witchhazel, River birch Spiny witchhazel gall aphid Hamamelistes spinosus 171 – 6 Control target
Birch Birch leafminer Fenusa pusilla  190 290 RU Larvae (1st generation)
Conifer Spruce spider mite Oligonychus ununguis 190 363 RU Immatures/Adults
Honeylocust Honeylocust pod gall midge Dasineura gleditchiae 192 229 RU Larvae
Holly Holly leafminer Phytomyza ilicis 192 290 RU Egg hatch
Holly *Native holly leafminer Phytomyza ilicicola 192 298 2 Egg hatch
Rhododendron Rhododendron borer Synanthedon rhododendri 192 298 2 Typical treatment window
Larch Larch sawfly Pristophora erichsonii 192 299 2 Typical treatment window
Andromeda Andromeda lacebug Stephanitis takeyai 192 303 RU Adults
Rhododendron Rhododendron gall midge Clinodiplosis rhododendri 192 363 RU Larvae
Willows, Cottonwood, Poplar Imported willow leaf beetle Plagiodera versicolora 192 448 RU Larvae/Adults
Privet Privet thrips Dendrothrips ornatus 192 618 2 Typical treatment window
Lilac, ash, privet, many Lilac / Ash Borer Podosesia syringae 200 299 RU Adults – 1st Treatment
Spruce Spruce budworm Choristoneura fumiferana 200 300 5 Larvae
Elm Elm leafminer Fenusa ulmi 215 240 5 Adult emergence
Wild and cultivated roses Roseslug sawfly Endelomyia aethiops 230 – 6 Egg hatch / early instars
Deciduous, many Hawthorn lacebug Corythucha cydoniae 239 363 RU Nymphs/Adults
Conifer Arborvitae leafminer Argyresthia thuiella 245 360 RU Larvae Treatments
Prunus American plum borer Euzophera semifuneralis 245 440 5 Adult flight, egg laying
Boxwood Boxwood mites Eurytetranychus buxi 245 600 RU All Stages
Lilac Lilac leafminer Caloptilia syringella 246 363 5 Larvae Treatments
Holly Holly leafminer Phytomyza ilicis 246 448 RU Larvae Treatment
Yew Taxus mealybug Dysmicoccus wistariae 246 618 RU Adults/Crawlers
Conifer Pine sawflies (Red-headed) Neodiprion lecontei 246 1388 RU Larvae (1st generation)
Boxwood Boxwood leafminer Monarthropalpusi flavus 249 – 6 Adult emergence
Conifer Eastern spruce gall adelgid Adelges abietis 250 310 5 egg hatch, galls begin forming (not a control target)
References RU Rutgers Cooperative Extension – 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

 

Boxwood Blight risk-model information, considerations, and links:

Boxwood Blight Risk Assessment as of 4/15/2021
Region Location CODE 15-April 16-April 17- April 18-April 19-April
Southern Upper Deerfield NJ50 Low  Very Low  Very Low  Very Low  Very Low 
Central Howell / Freehold NJ10 Low  Very Low  Very Low  Very Low  Very Low 
Northern High Point NJ59 Very Low  Very Low  Very Low  Very Low  Very Low 
Please check your local boxwood blight risk at (https://uspest.org/risk/boxwood_app)

 

Considerations:

Become a Boxwood Blight Advocate to receive quarterly updates (through the Horticultural Research Institution)

Filed Under: Landscape, Nursery, & Turf, Nursery, Turf Tagged With: , , , , , , , , , , ,
March 29, 2021

Nursery Pest Scouting Guide: 60-150 Growing Degree-days & Boxwood Blight Information

Pest Scouting:

Please print or download the two resources of this post (click on them): 

The information provided in the downloads gives scouting ranges (in growing degree days, base 50F) for specific insect pests harming nursery crop production and maintenance. Additionally, forecasting predictions (GDD50 accumulation) for calendar dates of multiple regions of New Jersey (S,N,C) are provided.

To determine your local growing degree-days, please review this post “Obtaining your local growing degree-day information”

Scouting Ranges:

  • This document supports scouting, it does not replace it. Keeping good notes on pest development will help dial in scouting and treatment efforts at your local level.
  • 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.
  • If you need more information, OR you are regularly seeing specific pest development stages at growing degree-days different than those listed here, please contact Tim Waller at twaller@njaes.rutgers.edu

GREAT RESOURCE from Steve Rettke: “Landscape Pest Notes: Some Early Spring Insects/Mites”

 

Projected GDD50 accumulation as of 3/29/2021
Region Location April 1st May 1st June 1st July 1st August 1st
Southern Upper Deerfield (NJ50) 75 185 591 1269 2111
Central Howell / Freehold (NJ10) 61 142 490 1111 1906
Northern High Point (NJ59) 24 30 242 695 1301
Forecast: NOAA NCEP Coupled Forecast System model version 2 (CFSv2) forecast system (3.5 months) (USPEST.ORG)

 

Pest Scouting – Growing Degree-day Ranges  (60-150 GDD50) 
CROP TYPE Common Name Scientific Name GDD Min (50F) GDD Max (95F) Reference Developmental / Target Stage
Many Southern red mite Oligonychus ilicis 69 157 RU Spring hatch
Conifer Eastern pine shoot borer Eucosma gloriola 75 200 4 1st adults active
Malus, Prunus, many Eastern tent caterpillar Malacosoma americanum 90 190 2 Larvae treatment before tents apparent
Many Gypsy moth Lymantria dispar 90 448 RU Larvae treatment (early instars)
Conifer Cooley spruce gall adelgid Adelges cooleyi 90 180 4 1st adults active – Douglas fir
Conifer Balsam twig aphid Mindarus abietinus 100 150 4 Stem mothers present (control target)
Conifer Pine engraver (Ips bark beetle) Ips spp. 100 150 4 1st adults active
Conifer European pine sawfly Neodiprion sertifer 100 195 4 1st larvae active
Pieris Andromeda lace bug Stephanitis takeyai 115 279 RU Nymphs (1st generation)
Azalea Azalea lace bug Stephanitis pyrioides 118 372 RU Nymphs (1st generation)
Conifer Larch casebearer Coleophora laricella 120 150 4 Egg hatch
Conifer Nantucket pine tip moth Rhyacionia frustrana 121 448 RU 1st generation egg hatch
Birch Birch leafminer Fenusa pusilla 123 290 RU Adults – egg laying
Many Gypsy moth Lymantria dispar 145 200 4 Egg hatch, 1st larvae
Holly Holly leaf miner Phytomyza ilicis 147 265 RU Adults – egg laying
Many Cankerworms, inch-worms, loopers (many) 148 290 2 Larvae treatment
Lilac, ash, privet, many Lilac / Ash Borer Podosesia syringae 148 299 2 Adult flight
Yews, Rhododendrons, many Black Vine Weevil Otiorhynchus sulcatus 148 400 2 Pupation / Adult emergence
Dogwood, many Dogwood Borer Synanthedon scitula 148 700 2 Adult activity
Conifer Spruce spider mite Oligonychus ununguis 150 175 4 1st egg hatch
Conifer Spruce needleminer Endothenia albolineana 150 200 4 1st larvae active
Conifer Balsam gall midge Paradiplosis tumifex 150 300 4 Adults laying eggs
References RU Rutgers Cooperative Extension – 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

 

Boxwood Blight risk-model information, considerations, and links:

Boxwood Blight Risk Assessment as of 3/29/2021
Region Location CODE 29-Mar 30-Mar 31-Mar 1-Apr 2-Apr
Southern Upper Deerfield NJ50 Very Low  Very Low  Very Low  Very Low  Very Low 
Central Howell / Freehold NJ10 Very Low  Very Low  Very Low  Very Low  Very Low 
Northern High Point NJ59 Very Low  Very Low  Very Low  Very Low  Very Low 
Please check your local boxwood blight risk at (https://uspest.org/risk/boxwood_app)

 

Considerations:

Become a Boxwood Blight Advocate to receive quarterly updates (through the Horticultural Research Institution)

Filed Under: Landscape, Nursery, & Turf, Nursery, Turf
March 22, 2021

Nursery Pest Scouting Guide: 25-60 Growing Degree-days (Southern NJ will hit approx. 45 GDD by Friday)

Please print or download the two resources of this post (click on them): 

The information provided in the downloads gives early season scouting ranges (in growing degree days, base 50F) for specific insect pests harming nursery crop production and maintenance. Additionally, forecasting predictions (GDD50 accumulation) for calendar dates of multiple regions of New Jersey (S,N,C) are provided.

To determine your local growing degree-days, please review this post “Obtaining your local growing degree-day information”

Scouting Ranges:

  • This document supports scouting, it does not replace it. Keeping good notes on pest development will help dial in scouting and treatment efforts at your local level.
  • 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.
  • If you need more information, OR you are regularly seeing specific pest development stages at growing degree-days different than those listed here, please contact Tim Waller at twaller@njaes.rutgers.edu

 

Projected GDD50 accumulation as of
NJ – Region Location March 1st April 1st May 1st June 1st July 1st
Southern Upper Deerfield (NJ50) 0 48 157 564 1241
Central Howell / Freehold (NJ10) 0 26 107 455 1076
Northern High Point (NJ59) 0 5 11 224 676
Forecast: NOAA NCEP Coupled Forecast System model version 2 (CFSv2) forecast system (3.5 months) (USPEST.ORG)

 

Pest Scouting – Growing Degree-day Ranges  (25-60 GDD50) 
CROP TYPE Common Name Scientific Name GDD Min (50F) GDD Max (95F) Reference Developmental / Target Stage
Conifer Eastern spruce gall adelgid Adelges abietis 25 100 3 Spring control of overwintering stage
Conifer Northern pine weevil Pissodes approximatus 25 100 4 1st adults active
Conifer Zimmerman pine moth Dioryctria zimmermani 25 100 3 1st larvae active
Conifer Cooley spruce gall adelgid Adelges cooleyi 25 120 3 Spring control of overwintering stage
Conifer White pine weevil Pissodes strobi 25 220 4 1st adults active
Shade trees European fruit lecanium Parthenolecanium corni 35 145 2 Spring control of overwintering stage
Many, evergreen Euonymus scale Unaspis euonymi 35 120 2 Spring control of overwintering stage
Conifer European pine sawfly Neodiprion sertifer 35 145 1 Hatched larvae
Conifer Fletcher scale Parthenolecanium fletcheri 35 148 2 Spring control of overwintering stage
Conifer European pine shoot moth / borer Rhyacionia buoiana 50 220 4 1st larvae active
Maples Maple bladdergall mite Vasates quadripedes 58 148 2 Spring control of overwintering stage
Honeylocust Honeylocust plant bug Diaphnocoris chlorionis 58 246 2 Nympths / adults active
Conifer Pine tortoise scale Toumeyela parvicornis 58 148 2 Cralwer activity
Conifer Pine bark adelgid Pineus strobi 58 618 2 Spring control of overwintering stage
Conifer Balsam twig aphid Mindarus abietinus 60 100 4 Egg hatch
References RU Rutgers Cooperative Extension – 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

 

(Please note: we will be providing pest GDD ranges regularly throughout the season for our green industries)

 

Important notes about growing degree-day models:

  1. These models do not replace scouting. They should guide scouting efforts and pest management programs, once the vulnerable life stage or economic threshold of a pest is recorded. Observations at a local level for specific pests is critical to IPM efforts and further refinement of degree-day-based predictions.
  2. GDD50 values for pest development are not exact, rather they should be viewed as a range. 
  3. The growing degree-day model (GDD50) is general by design. Some insect pests have specific formulas for their growth and development (some examples here). However, the GDD50 model is useful for many pests and plant species.
  4. Many GDD50 target values were developed in other parts of the country and should be ‘ground truthed’ at a local level. Blind applications of pesticides, without truthing pest development, may not deliver desired outcomes.
Filed Under: Landscape, Nursery, & Turf, Nursery, Turf
March 18, 2021

Early Season Conifer and Christmas Tree Pest Scouting List Using Growing Degree-days (base 50F)

Please print or download the two resources of this post (click on them): 

The information provided in the downloads gives early season scouting ranges (in growing degree days, base 50F) for specific insect pests harming conifer and Christmas tree production and maintenance. Additionally, forecasting predictions (GDD50 accumulation) for calendar dates of multiple regions of New Jersey (S,N,C) are provided.

To determine your local growing degree-days, please review this post “Obtaining your local growing degree-day information”

Scouting Ranges:

  • This document supports scouting, it does not replace it. Keeping good notes on pest development will help dial in scouting and treatment efforts at your local level.
  • 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.
  • If you need more information, OR you are regularly seeing specific pest development stages at growing degree-days different than those listed here, please contact Tim Waller at twaller@njaes.rutgers.edu

 

Projected GDD50 accumulation as of
NJ Region Location March 1st April 1st May 1st June 1st July 1st
Southern Upper Deerfield (NJ50) 0 24 133 540 1217
Central Howell / Freehold (NJ10) 0 14 95 443 1064
Northern High Point (NJ59) 0 1 7 220 672
Forecast: NOAA NCEP Coupled Forecast System model version 2 (CFSv2) forecast system (3.5 months) (USPEST.ORG)

 

Early Season Conifer Pest Scouting – Growing Degree-day Ranges Starting (0-300 GDD50)
Common Name Scientific Name GDD Min (50F) GDD Max (95F) Reference Developmental / Target Stage
Conifer rust mites Eriophyidae 7 22 4 Overwintering eggs hatch
Eastern pine weevil Pissodes nemorensis 7 58 RU Overwintering adults become active / prevent egg laying
Taxus mealybug Dysmicoccus wistariae 7 91 2 Spring control of overwintering stage
Cottony taxus scale Pulvinaria floccifera 7 91 6 Spring control of overwintering stage
Elongate hemlock scale Fiorinia externa 7 120 2 Spring control of overwintering stage
Spruce spider mite Oligonychus ununguis 7 121 RU Overwintering eggs hatch
Pales weevil Hylobius pales 7 121 RU Overwintering adults become active / prevent egg laying
White pine aphid Cinara strobi 22 91 RU Spring control of overwintering stage
Pine bark adelgid Pineus strobi 22 58 2 Spring control of overwintering stage
Spruce bud scale Physokermes piceae 22 120 2 Spring control of overwintering stage
Juniper scale Carulaspis juniperi 22 148 2 Spring control of overwintering stage
Eastern spruce gall adelgid Adelges abietis 25 100 3 spring control of overwintering stage
Northern pine weevil Pissodes approximatus 25 100 4 1st adults active
Zimmerman pine moth Dioryctria zimmermani 25 100 3 1st larvae active
Cooley spruce gall adelgid Adelges cooleyi 25 120 3 Spring control of overwintering stage
White pine weevil Pissodes strobi 25 220 4 1st adults active
European pine sawfly Neodiprion sertifer 35 145 1 Spring control of overwintering stage
Fletcher scale Parthenolecanium fletcheri 35 148 2 Spring control of overwintering stage
European pine shoot moth / borer Rhyacionia buoiana 50 220 4 1st larvae active
Pine tortoise scale Toumeyela parvicornis 58 148 2 Cralwer activity
Pine bark adelgid Pineus strobi 58 618 2 Spring control of overwintering stage
Balsam twig aphid Mindarus abietinus 60 100 4 Egg hatch
Eastern pine shoot borer Eucosma gloriola 75 200 4 1st adults active
Cooley spruce gall adelgid Adelges cooleyi 90 180 4 1st adults active – Douglas fir
Balsam twig aphid Mindarus abietinus 100 150 4 Stem mothers present (control target)
Pine engraver (Ips bark beetle) Ips spp. 100 150 4 1st adults active
European pine sawfly Neodiprion sertifer 100 195 4 1st larvae active
Larch casebearer Coleophora laricella 120 150 4 Egg hatch
Nantucket pine tip moth Rhyacionia frustrana 121 448 RU 1st generation egg hatch
Gypsy moth Lymantria dispar 145 200 4 Egg hatch, 1st larvae
Spruce spider mite Oligonychus ununguis 150 175 4 1st egg hatch
Spruce needleminer Endothenia albolineana 150 200 4 1st larvae active
Balsam gall midge Paradiplosis tumifex 150 300 4 Adults laying eggs
Spruce budworm Choristoneura fumiferana 200 300 4 1st larvae active
Cooley spruce gall adelgid Adelges cooleyi 200 310 4 1st galls visible – Spruce
Arborvitae leafminer Argyresthia thuiella 245 360 4 Larvae in mines; 1st generation
Eastern spruce gall adelgid Adelges abietis 250 310 4 Egg hatch, galls begin forming
Pine needle scale Chionaspis pinifoliae 298 448 4 1st generation egg hatch
Pine root collar weevil Hylobius radicis 300 350 4 1st adults active
Turpentine beetle Dendroctonus terebrans 300 350 4 Parent beetles colonizing brood material
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
6 https://extension.umd.edu/ipm/pest-predictive-calendar-landscapenursery

(Please note: we will be providing pest GDD ranges regularly throughout the season for our green industries)

 

Important notes about growing degree-day models:

  1. These models do not replace scouting. They should guide scouting efforts and pest management programs, once the vulnerable life stage or economic threshold of a pest is recorded. Observations at a local level for specific pests is critical to IPM efforts and further refinement of degree-day-based predictions.
  2. GDD50 values for pest development are not exact, rather they should be viewed as a range. 
  3. The growing degree-day model (GDD50) is general by design. Some insect pests have specific formulas for their growth and development (some examples here). However, the GDD50 model is useful for many pests and plant species.
  4. Many GDD50 target values were developed in other parts of the country and should be ‘ground truthed’ at a local level. Blind applications of pesticides, without truthing pest development, may not deliver desired outcomes.

 

Filed Under: Landscape, Nursery, & Turf, Nursery, Turf Tagged With: , , , , , ,
March 17, 2021

Obtaining your local Growing Degree-day information

Why use local growing degree-day models?

  1. You need to know local growing degree-day accumulation values to use pest scouting/management target lists like this. 
  2. Timing is everything in pest management! Degree-day models allow us to predict when to scout for pests and when to target vulnerable life stages of pest development.
  3. Growing degree-days (GDD50) refer to the of accumulation heating units, which are the average air temperature over a 24h period minus the minimum temperature threshold. To be considered a ‘growing’ degree-day, the minimum (or base) temperature threshold is 50°F.
  4. GDD50 can be used to determine when pest life stage events such as egg hatch, adult emergence, crawler activity, adult flight, and others are likely to occur.
  5. Many times plant and insect developmental stages coincide, thus Plant Phenological Indicators can be utilized to accurately scout for pests.
  6. Luckily, we do not need to manually enter or track this data due to the availability of FREE online tools.

Important notes about growing degree-day models:

  1. These models do not replace scouting. They should guide scouting efforts and pest management programs, once the vulnerable life stage or economic threshold of a pest is recorded. Observations at a local level for specific pests is critical to IPM efforts and further refinement of degree-day-based predictions.
  2. GDD50 values for pest development are not exact, rather they should be viewed as a range. 
  3. The growing degree-day model (GDD50) is general by design. Some insect pests have specific formulas for their growth and development (some examples here). However, the GDD50 model is useful for many pests and plant species.
  4. Many GDD50 target values were developed in other parts of the country and should be ‘ground truthed’ at a local level. Blind applications of pesticides, without truthing pest development, may not deliver desired outcomes.

Two examples of degree-day calculators with instructions:

USPEST.org (home page) delivers a wide variety of degree-day, climatic, and risk-based modeling tools for various applications in agriculture. This resource also has a number of important disease predictive tools such as the Boxwood Blight Risk Model. The USPEST growing degree-day application allows for day-to-day monitoring as well as historical and predictive data. The following directions seem complicated but after a few attempts, it is easy to become proficient with this incredibly powerful modeling system. Remember BASE TEMP MUST = 50°F (for all models to be considered a ‘growing’ degree-day model)

Table 1. Uspest.org – Degree-day / Phenology Model – quick reference guide
Step # Tab Sub-category Instructions Notes
– Intro – Educational Detailed instructions
1 Station Search bar Enter – area code, town, or weather station code example zip code: 08302
Drop-down menu Select – location of interest example: NJ50 = Upper Deerfield
2 Model Model Category Select – all models –
Model Select – degree-day calculator (general purpose) Many interesting degree-day calculators are available
Calculation Method Select – Simple average/growing dds  Average air temperature over 24 hours minus lower (base) temperature threshold
Lower Input – 50 ℉  50℉ : lower threshold must be used for ‘growing’ degree-day predictions/charts
Upper Input – 95 ℉ 95℉ : often used as upper temperature threshold value
Dates Select – date range Can be current, past, or future date ranges
Options Optional* – modify forecast type Default forecasting model: NMME (North American Multi-Model Ensemble)
3 Output Model Output Select – show full table (daily GDD accumulation) ‘DDs cumu’ = accumulated degree-days from selected start date
4 Graph Graph No action required Graphical display of current year, forecasts, and previous years based on ‘Dates’ selected
Link: https://uspest.org/dd/model_app

 

NEWA (homepage). Cornell University in cooperation with twenty-eight other groups and universities (including Rutgers) coordinate NEWA. NEWA contains a wide variety of robust degree-day models, climatic information and maps, and risk-based modeling tools for various applications in multitude crop systems. This resource also has a number of very useful, disease specific, predictive / monitoring / management tools for fruit, row, and vegetable crop diseases in addition to their growing degree-day model  (limited forecasting).

  • NEWA growing degree-day model instructions: State: select a state in the USA; Weather Station = find a local station from the list or click on the map; Degree-day type = Degree Days – Base 50. Then select the time range you wish to view. Once completed press Get Report. The results will display current and a 5-day forecast.

Informative resources: 

Please contact Tim Waller – Cumberland Co. Extension (Nursery Agent) if you need assistance setting up and using these powerful tools. (twaller@njaes.rutgers.edu)

Filed Under: Commercial Ag Updates, Landscape, Nursery, & Turf, Nursery, Turf Tagged With: , , , , , ,