- White mold has been reported in tomato and Southern blight in pepper in southern new Jersey this past week. Click here for more information.
- Early blight is being reported in tomato.
- Rhizoctonia root rot has been reported in summer squash. Click here for more information.
- Powdery mildew has been reported in cucurbit crops. For more information on the control of CPM please click here.
- Cucurbit downy mildew has been reported on cucumber in southern and central New Jersey and Eastern PA. For more information on CDM control please click here.
- Bacterial leaf spot has been reported in pepper. More more information on BLS control please click here.
- Bacterial canker has been reported in tomato. For more information on diagnosing important tomato diseases please click here.
- Early blight has been reported on potato.
- Phytophthora blight has been reported on pepper. For more information please click here.
- Dickeya dianthicola has been reported in potato in Virginia and Massachusetts.
- The 2022/2023 Commercial Vegetable Production Recommendations Guide is available for free online or for sale in hardcopy form at many County offices.
- For a quick review on managing fungicide resistance development using tank mixes and fungicide rotations, and information on FRAC group 4, FRAC group 7, and FRAC group 3 and FRAC group 11 fungicides please click on hyperlinks.
Vegetable Crops Edition
Seasonal updates and alerts on insects, diseases, and weeds impacting vegetable crops. New Jersey Commercial Vegetable Production Recommendations updates between annual publication issues are included.
Subscriptions are available via EMAIL and RSS.
Quick Links:
NJ Commercial Vegetable Production Recommendations
Rutgers Weather Forecasting - Meteorological Information important to commercial agriculture.
July 11, 2022 Andy Wyenandt
Vegetable Disease Update: 07-11-22
July 10, 2022 Andy Wyenandt
Identifying and controlling leaf mold in high tunnel & greenhouse tomato production
Leaf mold occasionally appears in high tunnel or greenhouse tomato production in New Jersey. However, under ideal conditions the disease will develop in field-grown crops. The fungus will cause infection under prolonged periods leaf wetness and when relative humidity remains above 85%. If relative humidity is below 85% the disease will not occur. Therefore, the proper venting of high tunnels and greenhouses on a regular basis is important. The pathogen can survive (overwinter) as a saprophyte on crop debris or as sclerotia in the soil. Conidia (spores) of the fungus can also survive up to one year in the soil.
Symptoms of leaf mold on infected tomato plant. Note bright yellow leaves and olive-green spores developing on undersides of leaves.
July 9, 2022 Andy Wyenandt
Important resources for cucurbit disease control in 2022
The cucurbit growing season is well under way in New Jersey and the rest of the mid-Atlantic region. Below are links to useful resources for the identification and management of important cucurbit diseases.
Diagnosing important diseases in cucurbit crops
Cucurbit Powdery and Downy Mildew: A Tale of Two Pathogens
The downy mildew forecasting website
Preparing for cucurbit downy mildew in 2022
Preparing for cucurbit powdery mildew in 2022
Preparing for Anthracnose and Alternaria Leaf Blights in Cucurbit Crops
Recognizing and controlling Angular leaf spot in cucurbits
Recognizing and controlling Plectosporium blight in cucurbits
Controlling Phytophthora and Pythium root rots
Destroying cucurbit plantings after harvest
July 8, 2022 Thierry Besancon
Recommendations for Under Plastic Mulch Weed Control
Plastic mulch, usually used with trickle irrigation, has many horticultural benefits for summer vegetable crops, and black plastic controls most annual weeds. Mulch does not solve all the weed problems in the field, and creates new challenges for the grower.
[Read more…]
July 8, 2022 Thierry Besancon
Update on Status of Dacthal Herbicide
DCPA (dimethyl tetrachloroterephthalate) is a selective preemergence herbicide used for control of annual grasses (foxtail, crabgrass, barnyardgrass, goosegrass, fall panicum) and some broadleaved weeds (purslane, common lambsquarters, pigweeds) in vegetable crops and ornamental turf. Commercial formulations of DCPA include Dacthal® Flowable herbicide. Dacthal® Flowable is labelled for use on the following vegetable and fruiting crop groups: cole leafy vegetables, seeded melons (cantaloupe, honeydew, watermelon), collards and mustard greens, horseradish and radish, onions, sweet potatoes, tomatoes and eggplants, strawberries.
- What is happening with DCPA, the technical ingredient in Dacthal® Flowable herbicide from AMVAC?
On April 27th the U.S. Environmental Protection Agency (EPA) published a notice of intent to suspend (NOITS) DCPA technical registration in the U.S. The basis for this action was that AMVAC had not provided multiple studies required during the registration review. - How did AMVAC and key grower stakeholders respond to this action by the EPA?
According to FIFRA (Federal Insecticide, Fungicide, and Rodenticide Act), AMVAC and impacted stakeholders had the opportunity to
appeal the NOITS within 30 days, which they did on May 27th. The purpose of the appeal was to obtain a hearing that would allow
evidence from each side to be presented in front of an Administrative Law Judge (ALJ) appointed by EPA. - Did AMVAC and the grower stakeholders have the opportunity for a hearing?
No. The assigned EPA administrative law judge (ALJ) ruled on Friday July 1st that the NOITS was upheld without requiring a hearing. - How will that impact end use formulated products like Dacthal Flowable herbicide?
This decision does not impact formulated products (i.e., Dacthal Flowable). AMVAC’s customers can continue to sell, distribute, and
apply Dacthal Flowable. - What happens now in this process concerning DCPA?
The July 1st decision granted EPA the ability to suspend DCPA technical without requiring a hearing to examine AMVAC and
EPA testimony. AMVAC will appeal this decision to the Environmental Appeals Board. - Is the registration of the end-use product Dacthal Flowable herbicide impacted by the NOITS?
If you have used or plan to use end-use products containing DCPA, there are no consequences from that use or downstream
consequence for the crop you applied it to, now or in the future, from NOITS activities. Applications of Dacthal Flowable end-use
products remain legal and the established United States tolerances remain in place. - What are the next steps in this process? How will it impact the availability of Dacthal Flowable?
AMVAC can continue to manufacture, sell, and distribute end-use products until notification of the appeal process has been completed. AMVAC’s customers can continue to sell, distribute, and apply Dacthal Flowable. AMVAC is commitment to continuing to exhaust all options to defend DCPA. Outside of any legal proceedings, AMVAC continues to generate and submit to EPA the data necessary to fulfill the Data Call-In (DCI) Notices required to complete registration review for DCPA, regardless of the suspension status.
July 8, 2022 Thierry Besancon
Herbicide Plant-Back Restrictions Explained: Purpose and Application
Are you crystal clear on the purpose of plant-back restrictions and on the length of time required between a herbicide application and the planting of your next crop or cover crop? If not, the guidance below should help. It was developed based on a poster presentation made during the 2022 annual meeting of the Weed Science Society of America (WSSA). For further information regarding the plant-back restrictions for vegetable crops, please refer to Pest Management section (p. 110-118) of the 2022/2023 Commercial Vegetable Production Recommendations.
- What is a plant-back interval?
A plant-back interval is the minimum period of time between a pesticide treatment and the planting of your next crop. The EPA establishes plant-back intervals as label requirements for herbicides, insecticides, fungicides, plant growth regulators and other types of pesticides. - What’s the purpose of a plant-back interval?
EPA’s primary focus in setting plant-back intervals is to protect human health by preventing over exposure to pesticide residues in crops – including fruits and vegetables. Regulatory experts include all residue sources when assessing human dietary exposure. - Do plant-back intervals also address crop phytotoxicity concerns?
While pesticide registrants may choose to add label instructions to address potential crop injury or phytotoxicity concerns, these instructions are independent of EPA-mandated plant-back restrictions that focus on limiting human exposure to pesticide residues. If your crop is intended to be harvested for human or animal consumption, you must still comply with the minimum residue-based plant-back intervals, regardless of whether phytotoxicity guidance is given. - How are plant-back intervals established?
EPA requires that pesticide registrants submit residue studies to document pesticide levels and related metabolites. Study data is then used to develop appropriate plant-back interval guidance based on allowed tolerance levels in the plant-back crop. All residue sources from pesticides applied within the current and previous growing seasons are included when assessing human dietary exposure. It is important to note that the plant-back intervals specified by EPA are crop specific. The interval specified for tomato, for example, might vary from that established for cole crops. - What should I do if I’m planting a crop that isn’t specified on the label?
Crops that are not specifically addressed on the label fall into the “other crops” category and require the maximum plant-back interval indicated on the label. - Do plant-back intervals apply to both my rotational crop and my cover crop?
If the crop is harvested for human consumption or is grazed by or fed to livestock that will be consumed by humans, the crop is considered a “rotational crop” and requires an appropriate plant-back interval to protect human health.
Seasonal plantings that will not be consumed directly by humans or by livestock that will then be consumed by humans are considered “cover crops.” Cover crops such as ryegrass or hairy vetch are grown to improve soil quality, reduce erosion or manage weeds. Since there is no risk of dietary exposure, plant-back restrictions do not apply when planting cover crops. - How do I calculate the plant-back interval?
To comply with the mandated plant-back interval, use the date of the last pesticide application as a starting point. If, for example, the crop selected has a 365-day plant-back interval, the 365-day window begins on the day after the last pesticide application to the previous crop. You can plant that next crop 365 days later.
