Did you know that according to the 2019 State Agriculture Overview for NJ, 3,900 acres of peaches yielded 5/tons per acre at a value of over $25.6 million dollars? Or that 3,500 acres of peppers were harvested in 2019, with a value of $45.8 million dollars? Or that 9,300 acres of harvested blueberries were valued at $85.3 million dollars in 2019? And in 2018, NJ ranked 4th nationwide in cranberry and peach production, and third in bell peppers?
July 17, 2020 Tim Waller
Participants Wanted for a Redheaded Flea Beetle Survey
The Southern Nursery Flea Beetle Working-Group has put out a survey under the auspices of University of Georgia. The Universities of Maryland and Delaware recently joined forces with that working group with the goal of gathering information aimed at suppressing this continually destructive pest. If you have seen redheaded flea beetle in your containerized nursery stock please take this short survey. Ultimately the goal is to gather as much information as possible about this pest in an effort to come up with better recommendations for all of us in the industry.
Please contact Tim Waller (twaller@njaes.rutgers.edu) with any questions, severely damaged plant varieties, or personal observations pertaining to pest control and biology.
Thank you
July 17, 2020 Rick VanVranken
NJ Ag & Health Urge Use of Free COVID-19 Testing For Farm Workers
Earlier this week, NJ Secretary of Ag Douglas Fisher released this attached letter, co-signed by Dept of Health Commissioner Judith Persichilli, urging all growers with farm labor to take advantage of opportunities to help protect your employees from COVID-19.
As the letter states,
“One program that is being implemented FREE OF CHARGE for all farms is a COVID-19 testing and education program through Federally Qualified Health Centers (FQHCs) and local health departments. Along with free testing, the program provides education and other related support services. [Read more…]
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.
Azalea Leafminers: Symptom stages from 3 leafmines & a single leafroller (Photo Credit: Steven Rettke of RCE)
June 24, 2020 Tim Waller
Prevailing landscape disease; Entomosporium Leaf Spot on woody ornamentals
Photo: Rich Buckley
It was brought to my attention this morning that many landscapers and plant professionals are concerned by a reddening and spotting discoloration condition on Photinia foliage. Most often this is caused by the fungal pathogen Entomosporium maculatum, a widespread and destructive foliar disease of woody ornamentals in the rose family (including Photinia, Indian Hawthorn, Loquat, flowering and fruiting Pear, Firethorn, Hawthorn, Juneberry, and Quince). This pathogen discolors foliage to an unsightly red, orange, and black spotting that ultimately leads to premature defoliation. The spots will eventually turn necrotic and fungal structures will be visible within those areas (little black dots).
Photo: Rich Buckley
The pathogen can be active from late winter to late fall, favoring conditions that promote humidity and reduced airflow. The pathogen survives on infected leaves (attached or dropped). Typically it takes approximately 2 weeks for symptom development to occur post infection. Therefor the heavy discoloration we are seeing right now is the culmination of multiple infection events, where protectant fungicides were not used or were used correctly.
This means that another round of infections will occur again soon in severely infected locations as the spots will give rise to a new generation of spores.
Disease management (fungicides): Ideally, protectant fungicide applications would have been initiated every 7-14 days post bud break until all leaves had matured. However, in the current situation many people will be playing catch up. Fungicide applications initiated now will not make the symptoms go away or ‘cure’ the plant, but they are required now to protect foliage from the next wave of fungal infections and reduce the overall population. In severely infected plantings, fungicide applications should be continued every 10-14 (depending on fungicide label) days throughout the remainder of the season, especially in high value plantings or in specimen blocks. If winter conditions are unseasonably warm and humid, then applications should continue accordingly. Systemic fungicides should also be considered in addition to protective and cultural control mechanisms in severe cases.
Fungicides:
ROTATE between Fungicide Resistance Action Committee (FRAC codes)
Format: [FRAC code]: Chemical name (Trade names)
- [M05]: Chlorothalonil (Daconil WS)
- [M05 + 1] Chlorothalonil + Thiophanate methyl (Spectro 90WDG)
- [1] Thiophanate methyl (Clearys 3336)
- [11] Azxystrobin (Heritage 50W)
- [3] Myclobutanil (Eagle 40W)
- [3] Propiconazole (Banner Maxx)
- [3] Triadimefon (Bayleton 50, Strike 50WDG)
- [1 + M03] Thiophanate methyl + Mancozeb (Duosan 79W)
- [M03] Mancozeb
- [M01] Copper Oxychloride + Copper Hydroxide (Badge SC, many)
IT IS CRITICAL TO ROTATE BETWEEN FRAC CODES DUE TO THE NUMBER OF POTENTIAL APPLICATIONS
Always refer to the label for allowable host crops, use-restrictions, application rates, reapplication intervals, re-entry intervals (REI), and mix compatibility information.
DISCLAIMER: Production and pesticide information on this site are for commercial operators 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.
Click here for a list of materials available to both homeowners and licensed pesticide applicators
Cultural prevention and mitigation:
- Remove leaf-litter prior to bud break. During the season remove leaf litter only when dry. Infected leaves serve as inoculum for the next season. In severely infected plantings remove and replace mulch as fungal material can be deposited within the litter. Do not use leaf blowers to remove leaf-litter (all that does is spread around the spores).
- Avoid overhead irrigation. Water moving through the canopy represents at least two dangerous plant pathogen situations; increased leaf wetness that lets pathogens infect successfully, and movement of spores (from sporulating leaves and young growth).
- Increase airflow. Like all plant diseases, any situation that increases airflow, will decrease leaf wetness. This could include pruning, decreasing the density of plants, greater spacing, and planting/rearing site selection.
- Pruning in heavily infected plants. In addition to promoting increased air flow, heavy pruning may be required to remove overwintering inoculum from the plants. This should only be done during dry conditions, preferably during plant dormancy periods.
For sample identification please contact the Plant Diagnostic Lab here at Rutgers.
Photo: Rich Buckley
For more information and tips please visit:
Controlling Entomosporium Leaf Spot on Woody Ornamentals
Photinia Leaf Spot – Prevention And Treatment Of Common Photinia Bush Diseases
Entomosporium Leaf spot of Photinia and Indian Hawthorn
Entomosporium Leaf Spot Diagnostic Guide
Timothy J. Waller, Ph.D. (twaller@njaes.rutgers.edu)
June 22, 2020 Tim Waller
Boxwood blight update for 6/22-6/26/20
There are consistently high infection potentials this week for boxwood blight.
Protective fungicide applications should remain in effect or be initiated immediately.
| Boxwood Blight Risk Model | ||||
| Date | Upper Deerfield (NJ50) | Howell (NJ10) | Pequest (NJ58) | |
| 6/20/20 | S | Low risk | Very low risk | Infection potential |
| 6/21/20 | Sun | Low risk | Infection potential | Infection potential |
| 6/22/20 | M | Infection potential | Infection potential | Infection potential |
| 6/23/20 | T | Infection potential | Infection potential | High Inf. potential |
| 6/24/20 | W | High Inf. potential | High Inf. potential | High Inf. potential |
| 6/25/20 | Th | Infection potential | Infection potential | Low risk |
| 6/26/20 | F | Very low risk | Very low risk | Low risk |
| — | — | — | — | — |
| ^Risk of infection^ | ||||
| adapted from: uspest.org/risk/boxwood_app | ||||
The weather: Don’t let these beautiful early summer days fool you, we all know that violent thunderstorms can appear out of nowhere, bringing with them high winds and rain (wind driven rain) causing high persistent humidity. I.e. the perfect storm for fungal pathogens to spread and successfully infect. Accordingly, many other fungal pathogens are equally active under these conditions and should be managed accordingly. Prevention is always easier than a cure.
These advisories are general in nature so someone from your business should be using this risk model if boxwood is important to your financial stability. In 30 seconds you can have a better idea of boxwood blight (and other pathogen) activity in your immediate area!
Boxwood blight information:
The disease may be sporulating and spreading amongst plantings if present (or may come into your nursery or landscapes via shipments) within the next few days. The pathogen, Calonectria pseudonaviculata, (aka Cylindrocladium buxicola) can also infect other hosts within the boxwood family (Buxaceae). These include common landscape plants such as Pachysandra and Sweetbox, so treatments should be directed towards these hosts as well. Leaf-litter suspected of boxwood blight should only be removed carefully under dry conditions (i.e. do not use a leaf blower to remove leaf-litter in Pachysandra or Boxwood plantings this week!). Additionally, please refrain from touching the plants at all during wet conditions as boxwood blight spores are sticky and can be transferred from plant-to-plant or site-to-site. Please follow proper sanitization and sterilization practices in addition to a preventative spray program. Tools, clothing, and transportation equipment should be routinely cleaned with alcohol or bleach to prevent the spread of this disease. Additionally, this pathogen forms small (yet bomb-proof) survival structures (Microsclerotia) that can remain as a source of infections for 7-10 years within the soil and leaf-litter (part of why you do not want to use a leaf blower to clean out leaf-litter!).
See the following for what to do in multiple boxwood blight scenarios.
Boxwood blight key symptoms:
- Straw-yellow to bronzing leaves that have a characteristic halo of lighter brown and yellow around the infection point.
- LEAVES FALL OFF, TYPICALLY STARTING AT THE BOTTOM. These leaves then act as a source for new infections.
- Twigs will have long brown lesions
Look-a-likes: NOT ALL FOLIAR DISEASES are Boxwood blight:
- Volutella Blight (straw-yellow or golden leaves with pink spores, branches have loose bark).
- Macrophoma leaf spot (straw-yellow leaves with black fungal structures (black spots))
Fungicides;
ROTATE between Fungicide Resistance Action Committee (FRAC codes)
Format: [FRAC code]: Chemical name (Trade names)
- [M05]: Chlorothalonil (Daconil WS)
- [M05 + 1] Chlorothalonil + Thiophanate methyl (Spectro 90WDG)
- [11] Trifloxystrobin + [7] Fluopyram (Broadform)
- [11] Trifloxystrobin + [3] Triadimefon (Armada 50WDG)
- [M03] Mancozeb
- [12] Fludioxonil (Medallion WDG)
- [3] Tebuconazole (Torque)
Always refer to the label for allowable host crops, use-restrictions, application rates, reapplication intervals, re-entry intervals (REI), and mix compatibility information.
DISCLAIMER: Production and pesticide information on this site are for commercial operators 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.
Previous Boxwood Blight Plant and Pest Advisory Posts;
- Immediate potential for boxwood blight activity (by Tim Waller)
- Boxwood blight revisited (by Rich Buckley)
- Boxwood blight confirmed in New Jersey (by Rich Buckley)
Additional resources on boxwood blight;
- NC State: Effective materials for boxwood blight
- Virginia Tech extension: Cultural practices and resistant varieties
- Perdue Extension boxwood blight
- University of Kentucky Extension boxwood blight
- Nursery Magazine “Reclaiming boxwood from boxwood blight”
- NJ Department of Agriculture boxwood blight guidelines
Contact: Timothy J. Waller, Ph.D. (twaller@njaes.rutgers.edu)
