ALERT – Control window approaching for Cryptomeria and Elongate Hemlock Scale

Cryptomeria Scale, Elongate Hemlock Scale, and Bagworms in Conifers – Control Window Approaching!

Projected GDD50 accumulation as of 5/23/2024 (for June – July)
CODE Location 23-May 1-Jun 15-Jun 1-Jul 15-Jul
NJ50 Upper Deerfield (South) 501 678 977 1383 1786
D2738 Mays Landing (South) 500 667 943 1327 1711
NJ10 Howell (Central) 407 568 833 1203 1577
NJ36 Parsippany (Central) 389 548 795 1141 1491
E7133 Belvidere (North) 432 592 836 1178 1523
N59 High Point (North) 345 486 706 1020 1338
USPEST.ORG – Model: simple average/growing degree-day, Min: 50F – Max: 95F, NMME forecast
Forecast:  7-month NMME based seasonal climate forecast (USPEST.ORG) – Subject to change regularly = Check Often

 

Cryptomeria Scale – Click here for full Cryptomeria Scale write-up (with pictures)

(Adapted from Steve Rettke – RCE post above)

Crawlers Generation 1: 600-800 GDDs (first few weeks of June in NJ)

  • Similar to many other armored scale species, the Cryptomeria scale has more than one generation of crawlers during the growing season. In New Jersey, this scale has two crawler generations per year, Crawlers are lemon yellow in color & because of the color contrast can typically be easy to observe on needles, even without a hand lens. Unfortunately, the crawler emergence periods of both generations of the Cryptomeria scale are not restricted to only a week or two. Their more prolonged crawler periods can extend for 4 weeks or even longer, although a large percentage of crawlers will occur during the first 2 weeks after emergence begins.

Crawlers Generation 2: 1750-2130 GDDs (end of July early August in NJ)

Control options: When applying control materials with short residuals (e.g., horticultural oils), the use of multiple applications will probably be required to achieve a more complete crawler suppression. If a single application is desired, then oils plus synthetic pyrethroids can provide a 3-week residual. Examine infested trees closely to determine if significant predators or parasitoids are presently active. When numerous, these beneficials can be extremely valuable to help with suppression. Therefore, the use of horticultural oil applications alone will help conserve the beneficials & still control crawlers when coverage is adequate. The use of most of the neonicotinoid insecticides (e.g., Merit) will not achieve satisfactory controls (maybe only 30-40% efficacy). However, the usage of dinotefuran (Safari) as a soil drench or bark spray has been shown to give excellent results against armored scales, with some studies showing 90% efficacy. The extremely high-water solubility of Safari allows this material to penetrate the plant cells where the scales are feeding.

Elongate Hemlock Scale – Click here for more information (with pictures)

(Adapted from Steve Rettke – RCE post above)

First crawler emergence: 360-700 GDDs (Late May – June in NJ)

  • Female covers are oval, flat, tan/translucent; males are whitish. There may be six or more scales per needle. Yellow spots appear on needles under light feeding and foliage appears thin; in heavy infestations, needle drop occurs, and trees may be killed. Adult females have an exceptionally long egg-laying period (lasting throughout the summer) with two overlapping generations. Crawlers (immatures) are noticeable in late May, in conjunction with new growth. Although there are only two generations per year, crawlers can emerge over an extended period. Look for the tiny crawlers using a 10-15x hand-lens.

Control options: Pyriproxyfen (Distance) is an insect growth regulator & can provide good suppression. It is classified as a “reduced risk” material by the EPA. Dinotefuran (Safari) is a neonicotinoid that has been a product of choice to control armored scales for more than a decade. Imidacloprid (Merit) is highly effective controlling the hemlock woolly adelgid but will not provide satisfactory control of elongate hemlock scales. Acephate (Orthene) has translaminar properties within foliage & can provide some suppression.

 

Bagworms 

Days old bagworm size

Days-old bagworm = critical management target – T. Waller – RCE

Bagworms should begin hatching NOW through – 4 weeks in NJ, beginning in the southern regions. Now is an optimal time to get this pest on your radar and prepare materials or approaches to attack first/second instar caterpillars. The control window for this pest is typically between 600-900 GDD50  when they begin to hatch and become airborne, i.e. the “ballooning” phase. It is important to check for egg-hatch prior to applications for greatest chemical efficacy, and to continue scouting as they often hatch and develop at asynchronous rates.

It is critical to target these insects EARLY!

Bagworm management – mechanical: If eggs have not hatched: hand-remove sacs/bags. Typically female/egg filled sacs are higher in the canopy so keep that in mind while scouting. This removes the problem from the field or landscape.

Treatment options for Lepidoptera (caterpillars) to have at the ready – containing: B.t. (Bacillus thuringiensis), spinosad , bifenthrin ), cyfluthrin, carbaryl, chlorantraniliprole, cyclaniliprole, cyclaniliprole + flonicamid, Lambda-cyhalothrin, cyantraniliprole, Indoxacarb.  NOTE – Lethal pesticide doses are important, as sub-lethal doses can trigger early pupation, making the pest all but invincible to chemical or biological treatments. Follow label exactly.

IT IS CRITICAL TO ROTATE MATERIALS (Rotate between IRAC groups) 

DISCLAIMER: The label is the law, always refer to it for allowable host crops, use-restrictions, application rates, reapplication intervals, re-entry intervals (REI), and mix compatibility information. Production and pesticide information on this site are for private/commercial pesticide applicators and landscape professionals only, and are NOT for home gardener use. Provided materials represent examples and do not cover all possible control scenarios. Please contact your local agent or chemical sales representative for more information or to discuss additional pest management options.

BAGWORMS (600-900 GDD) (Bagworm hatch prediction as of 5/20/24)
Crop type Common Name Scientific Name GDD Min (50F) GDD Max (95F) Reference Developmental / Target Stage
Conifer mostly, many minor hosts Bagworm Thyridopteryx ephemeraeformis 600 900 RU Larvae (early instars) – ONLY CONTROL WINDOW
Region Location Station Date (600 GDD) Date (900 GDD) *Treatment window  *Bagworm Hatch – Predictions only, SCOUTING is critical! Treat as soon as larvae detected.     

Remove any ‘bags’ prior to hatch if possible

South Upper Deerfield NJ50 29-May 12-June 13 days
Central Howell / Freehold NJ10 4-June 19-June 15 days
North High Point NJ59 11-June 26-June 15 days 

 

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.

Nursery Pest and Disease Update 6/15/2023

In this edition:

  • Insects:
    • MORE Scale crawlers emerging
    • Borers
    • Beetles
  • Diseases:
    • Oomycete root diseases (Phytophthora, Pythium, Phytopythium)
    • Leaf spots / foliage diseases
    • Boxwood Blight – reminder
    • Virus observations
  • Nutrient Management 
    • Managing Soluble Salts by monitoring EC
    • Plant Tissue analysis
  • Plant Spotlight:
    • American Holly (Ilex opaca)
  • Cumberland Nursery / NJNLA – Twilight: tonight (6/15) for NURSERYMEN ONLY (contact twaller@njaes.rutgers.edu or 856-451-2800 Ext. 1. for details)

Please click “read more” below to get updates on pests, diseases, and other important resources for the week of 6/15/2023.

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Conifer Pest and Disease Update 5/15/2023

In this edition:

  • Insects – Pest Scouting with growing degree-days (250-600 GDD50)
    • Scales
    • Mites
  • Diseases
    • Needle casts (Rhabdocline and Swiss needlecasts – Douglas fir, & Rhizosphaera – spruces)
    • Phytophthora
  • Soil fertility – resources

Please click “read more” below to get updates on pests, diseases, and other important resources for the week of 5/15/2023.

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Nursery Pest and Disease Update 5/15/2023

In this edition:

  • Insects:
    • Scale crawler emergence
    • Borer insects
    • Upcoming problem pests / Redheaded flea beetle / SLF / Pest Scouting Guides
  • Diseases:
    • Leaf spot / foliage disease management
    • Fire blight on Rosaceous hosts
    • Canker fungi
    • Boxwood blight
    • Oomycete root diseases (Phytophthora, Pythium, Phytopythium)
  • Plant Spotlight:
    • NJ native azalea species

Please click “read more” below to get updates on pests, diseases, and other important resources for the week of 5/15/2023.

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Pest Scouting 200-500 GDD – Get sprayers ready for Borers, Scale Crawlers, and other important pests

It’s that time of year again, many scale crawlers and borers will be active over the next few weeks throughout NJ. Be prepared to target specific pest life-stages for the highest level of efficacy per material cost and get those problem insects in check. Application of contact insecticides during specific activity windows for these pests should be coupled with systemic applications now to help protect woody plants later on.

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)   

Please Download these resources: (The scouting guide is for you to print and keep on hand…these are just updates)

Nursery and Landscape Pest Scouting Guide 2022 PDF (note this contains conifer pests as well)

Conifer Pest Scouting Guide 2022 PDF

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

Projected GDD50 accumulation as of 5/13/2022 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-May 1-Jun 1-Jul
South Upper Deerfield NJ50 297 603 1323
Central Howell / Freehold NJ10 242 508 1160
North High Point NJ59 135 345 867
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 

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