Plant Diagnostic Lab — Page 13 — Plant & Pest Advisory

January 2, 2021 Steven K. Rettke

Diplodia Tip Blight: The Key to Infections is Found Within the Cones

Diplodia Tip Blight (Diplodia pinea) is a fungus disease in the landscape commonly observed on Austrian pines (Pinus nigra), but can also be found infecting mugo, red, black, & Scots pines. This blog will emphasize with photos the infections seen on Austrian pines.

The symptoms of Diplodia Tip Blight are stunted or dead shoots. With extensive infections, almost every branch & twig can be affected as the disease spreads over the years. The lower branches of the Austrian pines are usually infected first. For numerous years, the upper canopy will initially show few symptoms. The fungus kills developing needles in the spring, resulting in dead candles that are deformed & much shorter than the growth found on healthy twigs.

Austrian pine with obvious symptoms from Diplodia Tip Blight infections. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Stunted or dead newly emerged twig shoots on Austrian pine branch. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

December 13, 2020 Steven K. Rettke

Primer on Anti-Transpirant Applications

Purpose

During the weeks of late fall & early winter, many landscapers apply their annual anti-desiccant sprays to broadleaf evergreen plants. Some of the common trade names of these liquid resin, spray-on products include Vapor-Guard, Wilt-Pruf, Stress Guard, and Nu-Film. Although plants go dormant during the winter, evergreens will continue to transpire given certain conditions. These applications help reduce excessive water loss from leaves during the dry winter months when the ground is frozen. An anti-transpirant is a film-forming complex of polyethylene’s and polyterpenes that when applied to foliage will reduce the moisture vapor transmission rate. Although much of the transpiration from leaves occur through small openings (stomates) under the leaves, a significant amount of water loss can also occur directly through the leaf cuticle or epidermis. The anti-transpirants function by increasing cuticle thickness of broadleaf evergreens.

This Rhododendron may have some winter injuries, but the primary cause for the plant decline is from wood borers. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Desiccated holly leaves (Winter Burn) with obvious symptoms. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

December 7, 2020 Steven K. Rettke

A Primer on Dormant Oil Applications

Dormant Oil Guidelines:

Dormant oils at 2-4% rates in the late fall & late winter seasons can aid in the control of overwintering insects and insect eggs. Consider treating for such pests as aphids (eggs), southern red mites/eggs, spruce spider mites/eggs, oak spider mites (eggs), eriophyid mites/eggs, spruce gall adelgids, lace bugs (deciduous plants), cankerworms (eggs), leaftiers, psyllids, plant bugs, etc.

Some landscapers have been successful applying both late fall and early spring dormant oil treatments to the same plants on the same properties. This is a reasonable approach since a single dormant oil treatment will not provide 100% control and it gives the field technician another opportunity to monitor the landscape for problems.

Dormant oil sprays require excellent coverage & often repeat applications. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

Japanese maple scale infested branch will likely require multiple dormant oil treatments to suppress. (Photo Credit: Steven K. Rettke, Rutgers Coop. Ext.)

September 15, 2020 Tim Waller

Register for the September Nursery Twilight Meeting (credit-bearing online webinar)

Thursday, September 24^th, 2020

6:00-7:00 pm

Click here to register for the twilight meeting

Registration password: nursery

Click here to upload your government issued photo ID prior to the meeting

We will NOT be checking photo-IDs within the actual session this time around (to better protect your information). However, you will still need to be visible on screen to acquire recertification credits.

Upload directions: If you click on the photo ID upload link using a smart phone/tablet you will have the option of simply taking a photo of your ID and uploading it directly into the system. Otherwise, you can scan a copy of your photo ID into a computer and follow the directions at the upload link. If you are unable to upload documentation prior to the meeting, don’t worry, we are here to help; Tim Waller will work with you to verify your identity for NJDEP recertification credit purposes using the attendance roster to contact individuals that are seeking credits.

Please note: the file upload goes to a secure Rutgers folder and no one other than the session host (Tim Waller) can view. Also, if you upload your information for the September meeting and plan to attend an October meeting, you will not need to upload your information again (good for 60 days).

September 2020 Nursery Crop Twilight Meeting

NJ Pesticide License Recertification credits obtained: PP2 (2); 3A (2); 10 (1)

Online Program

5:30pm Webinar opens and visual attendance check

–Timothy Waller, Rutgers Cooperative Extension Agriculture Agent for Cumberland County

(Recording begins) : Welcome Remarks

6:00pm Preparing for a successful season; Understanding the factors that contribute to pest and disease outbreaks– Timothy Waller, Rutgers Cooperative Extension Agriculture Agent for Cumberland County

6:15pm Emerging pests and diseases of New Jersey nursery crops – Rich Buckley, Rutgers Plant Diagnostic Laboratory and Nematode Detection Service, Director

6:30pm Cultivating sustainable soils in ornamentals– Bill Errickson, Rutgers Cooperative Extension Agriculture Agent for Monmouth County

6:45pm Effective nutrient management via fertigation– Raul Cabrera, Rutgers Extension Specialist in Nursery Production & Management

(Recording ends)

7:00pm Additional questions; Adjourn

In cooperation with the NJNLA, NJLCA, and NJCTGA

Instructions:

Register for event at the above link
Include your pesticide license number and date of birth if you would like recertification credits
After registration you will receive a confirmation email with a link to the actual twilight meeting.
Upload a copy of your government issued photo ID at the link above
Day-of: click the link in the registration confirmation email and select “join by browser-New” around 5:30pm
Day-of: Have your video on if you wish to obtain credits

Additional requirements for those seeking credits:

Licensed applicators with a recertification period expiring October 31, 2020 will be given an exemption from the NJDEP online credit cap of 25% and are eligible for all credits, otherwise this exemption does not apply.
Verification of identity is required prior to or in short duration after the meeting
Attendees must be visible throughout the entire session (with live video on) and must stay to the end.
Polls can be randomly scheduled, & attendance will be visually monitored by a moderator.
Call-ins (audio only) are not eligible for pesticide recertification credits as of now; you need a computer/phone/tablet with *live* video capability.

We are here to help you connect, please contact Tim Waller (twaller@njaes.rutgers.edu) with any questions or concerns. Thank you very much for your willingness to cooperate within our online space!

Rutgers is dedicated to protecting your privacy and keeping your personal information safe. Your information will be kept strictly confidential; used solely to meet NJDEP ID verification protocol for recertification credit. Any information will be deleted after 60 days.

Filed Under: Landscape, Nursery, & Turf, Nursery, Plant Diagnostic Lab, Turf

July 23, 2020 Steven K. Rettke

Differentiating the Common Wood Borers of Ash Trees

Today, it is understandable for arborists and landscapers to assume that Emerald Ash Borers (Agrilus planipennis) are the cause when they observe branch die-back of ash trees (Fraxinus genus). During the 21st century, this invasive Asian tree beetle borer has killed many 100’s of millions of ash tree species as it has spread across much of the eastern half of the United States. However, it is important to remember some of the other wood borer species that cause ash decline, if not death. This blog will discuss the symptoms to distinguish between the Emerald ash beetle borer, the Ash/Lilac Clearwing moth borer (Podosesia syringae), the Banded Ash Clearwing moth borer (Podosesia aureocincta) and Ash Bark Beetle borers (Hylesinus species). Only the ash bark beetle species will have more than a single generation per season.

Symptoms on ash from banded ash clearwing moth borer infestation. (Photo Credit: Steven K. Rettke of RCE)

June 25, 2020 Steven K. Rettke

Azalea Leafminer: A Commonly Unrecognized Azalea Pest Problem

The Azalea Leafminer (Caloptilia azaleella) produces plant symptoms that are typically subtle & can often be overlooked. Symptoms from this caterpillar can also confuse people by having both leafminer & leafroller stages. The early instar stages are leafminers, while the later instar stages are leafrollers or leaftiers. Commercial nurseries generally have more concerns with this pest, while they often receive little attention in the landscape. Although the Azalea Leafminer has 2+ generations per year, the azalea (Rhododendron genus) is the only known host of this native caterpillar having the unique one-two punch.