Rutgers University | New Jersey Agricultural Experiment Station | Pesticide User Responsibility

Archives for July 2022

July 10, 2022

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 the bright yellow leaves and the olive-green spores developing on the undersides of leaves.

Symptoms of leaf mold on infected tomato plant. Note bright yellow leaves and olive-green spores developing on undersides of leaves.

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Filed Under: Vegetable Crops Tagged With: , , , ,
July 9, 2022

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

 

Filed Under: Disease Forecasting, Vegetable Crops Tagged With: , ,
July 8, 2022

Tree Fruit IPM Report for July 8, 2022

Peach:

Oriental Fruit Moth: A biofix point for OFM was set on 4/11 in southern counties, and on 4/14 in northern counties. The third generation timings are updated below.

Insecticide Type
County/Region Degree Days by  7/8 base 45 Conventional

2000-2100 2350-2450

 Diamide

2025–2150 2375-2450
Gloucester – Southern 1772 1st –7/14-7/16

2nd –too far off

 1st –7/14-7/17

2nd –too far off
Middlesex – Northern 1701 1st –7/16-7/18

2nd –too far off

 1st –7/16-7/19

2nd –too far off

 

Japanese Beetles: Japanese beetles have emerged and have been observed in some orchards. Products containing imidacloprid (Admire Pro, etc.) are effective and have a short preharvest interval. See the Tree Fruit Production guide for more information.

Tarnished Plant Bugs; and Other Catfacing Insects: Catfacing insect activity is increasing with the arrival of hot weather and is present at moderate to high levels in some orchards.

Scale Inesects: First generation San Jose Scale crawler emergence is just about over. The next crawler emergence will start in late mid to late July for both San Jose and White Peach scale and will last well into August. White Peach scale has a third generation in September and San Jose scale may have a third generation in October. Esteem, Centaur and Movento are all good scale materials. Esteem and Centaur should be applied at the start of crawler emergence. Movento should be applied before the start of the crawler emergence and needs to be applied with a penetrant. Observations over the years indicate that Movento may not work well as we move into late summer especially on Pome Fruit. Other options include The neonicitinoids, Closer, Sivanto and Venerate. Some may need more than one application.

Apples and Pears:

Diseases: Summer scab, rots and sooty blotch and fly speck are the main targets at this stage. Where scab is present rely primarily on protectant fungicides. Last year Captan plus a phosphorous acid like Prophyt was observed to slow scab development as well as provide good summer disease control. Bitter Rot symptoms are now appearing in susceptible varieties.

Brown Marmorated Stink Bugs: Brown Marmorated Stink bugs are present at low to moderate levels in orchards statewide. Eggs are hatching and nymphs are present. See the NJ Tree Fruit Production guide for effective materials.

Codling Moth (CM): Timings for the second generation are updated below.  A biofix was set for CM on April 25th in southern counties, and May 6 in Northern counties (Middlesex County). Estimated timings for the second generation are updated below.

Codling Moth Degree Day Timing
Application and Insecticide Type
County Area Biofix Intrepid; Diamides – Altacor, Voliam mixes:

1150-1200 +

1450-1500 DD

 

 Cyd-X, Madex

1250 DD + every 7-9 days during brood hatch (later if first spray is an IGR)

 Standard Insecticides –  Delegate, Avaunt, OP’s, carbamates, pyrethroids

1250 DD +

1550-1600 DD

 
DD 1150-1200 1450-1500 1250 1250 1550-1600
Southern April 25 7/3-7/5 7/14-7/16 7/7 7/7 7/18-7/20
Northern May 6 7/6-7/7 7/17-7/19 7/9 7/9 7/21-7/23

Scale Insects: For San Jose scale see the peach section above.

Tree  Fruit Trap Counts – Southern Counties

Weekending STLM TABM-A CM BMSB OFM-A DWB OFM-P TABM-P LPTB PTB
4/9/2022 2 0 0
4/16/2022 0 2 3
4/23/2022 11 0 0 28 5 0 0
4/30/2022 5 0 1 31 4 0 0
5/7/2022 5 1 3 50 4 0 0
5/14/2022 8 5 3 19 2 0 0
5/21/2022 3 5 5 20 2 7 3
5/28/2022 0 19 3 13 0 11 36
6/4/2022 0 10 3 5 1 13 49 0
6/11/2022 0 9 2 6 36 0 8 47 3
6/18/2022 0 4 1 0 62 0 3 13 1
6/25/2022 16 0 0 6 3 16 0 0 18 4
7/2/2022 24 0 0 6 3 24 0 0 18 4

 

Tree  Fruit Trap Counts – Northern Counties

Weekending STLM TABM-A CM BMSB OFM-A DWB OFM-P TABM-P LPTB PTB
4/9/2022
4/16/2022 0 0 1
4/23/2022 0 0 2 0
4/30/2022 0 0 2.5 0
5/7/2022 0 1 4 0
5/14/2022 1 2 0 5 0.5 0 0
5/21/2022 6 8 4 27 2 5 6 5 0
5/28/2022 34 19 3 6 13 1 23 15 0
6/4/2022 17 21 4 4 11 1 27 17 0
6/11/2022 22 25 2 1 4 0 30 9 0
6/18/2022 66 20 2 2 2 5 2 27 7 0
6/25/2022 58 21 1 8 8 2 4 22 4 0
7/2/2022 55 7 1 1 14 15 2 9 4 1

 

Pest Event or Growth Stage Approximate Date 2022 Observed Date
 Bud Swell (Redhaven)  March 23 +/- 15 Days March 20
1/4″ Green Tip Red Delicious March 31 +/- 13 Days March 21
Pink Peach (Redhaven) April 4 +/- 15 Days March 31
Tight Cluster Red Delicious April 9 +/- 13 Days March 31
Full Bloom Peach (Redhaven) April 9 +/- 14 Days April 10
Pink Apple (Red Delicious) April 14 +/- 12 Days April 14
Full Bloom Apple (Red Delicious) April 22 +/- 11 Days April 21
Petal Fall (Redhaven) April 22 +/- 10 Days April 14
Petal Fall (Red Delicious) April 27 +/- 13 Days May 3
Shuck Split (Redhaven) April 30 +/- 11 Days April 26
Pit Hardening June 15 +/- 9 Days June 10

 

Filed Under: Tree Fruit Tagged With: , , , , , ,
July 8, 2022

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.
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Filed Under: Vegetable Crops Tagged With: , , ,
July 8, 2022

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.

 

 

Filed Under: Strawberry, Vegetable Crops Tagged With: , , , ,
July 8, 2022

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.
Filed Under: Commercial Ag Updates, Field, Forage & Livestock, Food Safety, Fruit, Vegetable Crops Tagged With: , ,