Commercial Ag Updates + Farm Food Safety

Rutgers Cooperative Extension Ag Agents provide updates on what they see in the field, upcoming events, and other important news that affects your operation, such as developments in on-farm Food Safety. Subscribe if you wish to be notified about workshops, meetings, and upcoming commercial ag events.
 
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Greenhouse Disease Management: Seed Treatments and Transplant Production

Seed Treatment

Seed used in transplant production should be certified ‘clean’ or disease-free. Most commercial seed comes with certification and is pretreated with fungicide. Important diseases such as Bacterial leaf spot of tomato and pepper can cause major problems in transplant production if introduced in the greenhouse, especially if untreated seed is infested. Remember, a small amount of infested seed can be a major source of inoculum in the greenhouse and cause significant problems in the field later in the growing season.

As a rule for any crop, any non-certified or untreated seed should be treated, if applicable, with a Clorox treatment, or with hot water seed treatment, then treated pre-seeding or at seeding with fungicide(s) to help minimize damping-off diseases. Organic and conventional tomato growers who grow a significant number of heirloom vegetables, such as tomatoes, should consider using the hot water seed treatment to help reduce the chances for bacterial problems. Remember, Chlorox simply acts as a surface disinfectant, kllling pathogens that may reside on the surface of the seed. The hot water seed treatment method will also kill potential pathogens within the seed.

Hot Water Seed Treatment Method

Hot water seed treatment is a non-chemical alternative to conventional chlorine treatment which only kills pathogens on the surface of the seed. Heat-treatment done correctly kills pathogens inside the seed as well. If done incorrectly, it may not eradicate pathogens and may reduce germination and vigor. For cole crops, it is especially important to follow treatment protocols as seeds can split.

Seed heat treatment follows a strict time and temperature protocol and is best done with thermostatically controlled water baths. Two baths are required: one for pre-heating, and a second for the effective (pathogen killing) temperature. For cole crops, the initial pre-heating is at 100°F (38°C) for 10 minutes. The effective temperature is 122°F (50°C). Soaking at the effective temperature should be done for 20 minutes for broccoli, cauliflower, collards, kale, and Chinese cabbage, and 25 minutes for Brussels sprouts and cabbage. Immediately after removal from the bath, seeds should be rinsed with cool water to stop the heating process. After that, seeds should be dried on a screen or paper. Pelleted seeds are not recommended for heat treatment. Only treat seed that will be used in the current season.

As an alternative to hot water seed treatment, use 1 part Alcide (sodium chlorite), 1 part lactic acid, and 18 parts water as a seed soak. Treat seed 1-2 minutes and rinse for 5 minutes in running water at room temperature.

For more information on seed treatment methods please see page 124 in the upcoming 2020/2021 Mid-Atlantic Commercial Vegetable Production Recommendations Guide.

Transplant Production

Proper greenhouse sanitation is important for healthy, disease-free vegetable transplant production. Efforts need to be made to keep transplant production greenhouses free of unnecessary plant debris, soils, and weeds which may harbor insect pests and disease.

  • All equipment, benches, flats, plug trays and floors should be properly cleaned and then disinfested prior to use with efforts taken throughout the transplant production season to minimize potential problems.
  • Any weeds in or around the greenhouse structure should be removed prior to and after any production.
  • Any transplant brought into the greenhouse from an outside source needs to be certified ‘clean’, as well as visually inspected for potential insects and diseases once it reaches your location. Suspect plants should not be placed in the greenhouse.

Remember, disinfestants, such as Clorox, Green-Shield, or hydrogen dioxide products (Zerotol – for commercial greenhouses, garden centers and Oxidate – commercial greenhouse and field), kill only what they come into direct contact with so thorough coverage and/or soaking is necessary. The labels do not specify time intervals for specific uses, only to state that surfaces be ‘thoroughly wetted’. Therefore, labels need to be followed precisely for different use patterns (i.e., disinfesting flats vs. floors or benches) to ensure proper dilution ratios. Hydrogen dioxide products work best when diluted with water containing little or no organic matter and in water with a neutral pH. There are a number conventional and organic products labeled for disease control during transplant production in the greenhouse.

Sanitizing Greenhouse Surfaces and Treatment of Flats and Trays:

There are several different groups of sanitizers that are recommended for plant pathogen and algae control in transplant greenhouses. Alcohol is often used to disinfect grafting tools. All these products have different properties:

  • Quaternary ammonium chloride salts (Q-salts such as Green-Shield®, Physan 20®, KleenGrow™) are labeled for control of fungal, bacterial and viral plant pathogens, and algae. They can be applied to floors, walls, benches, tools, pots and flats as sanitizers.
  • Hydrogen Dioxide, Hydrogen Peroxide, and Peroxyacetic Acid containing products (ZeroTol® 2.0, OxiDate® 2.0, SaniDate®12.0) kill bacteria, fungi, algae and their spores on contact. They are labeled as disinfectants for use on greenhouse surfaces, equipment, benches, pots, trays and tools.
  • Chlorine bleach may be used for pots or flats, but is not recommended for application to walls, benches or flooring. When used properly, chlorine is an effective disinfectant. A solution of chlorine bleach and water is short-lived and the half-life (time required for 50 percent reduction in strength) of a chlorine solution may be as little as a few hours.

New flats and plug trays are recommended for the production of transplants to avoid pathogens that cause damping-off and other diseases. If flats and trays are reused, they should be thoroughly cleaned and disinfested as described below. Permit flats to dry completely prior to use. Styrofoam planting trays can become porous over time and should be discarded when they no longer can be effectively sanitized.

  • Sanitizing trays with Chlorine: Dip flats or trays in a labeled chlorine sanitizer at recommended rates (3.5 fl oz. of a 5.25% sodium hypochlorite equivalent product per gal of water) several times. Cover treated flats and trays with a tarp to keep them moist for a minimum of 20 minutes. Wash flats and trays with clean water or a Q-salts solution to eliminate the chlorine. It is important that the bleach solution remains in the pH 6.5-7.5 range and that a new solution is made up every 2 h or whenever it becomes contaminated (the solution should be checked for free chlorine levels at least every hour using test strips). Organic matter will deactivate the active chlorine ingredients quickly.

For more information on seed treatments and disinfectant products labeled for use in the greenhouse please see the upcoming 2020/2021 Mid-Atlantic Commercial Vegetable Production Recommendations Guide.

Selected Organic and Conventional Fungicides, Bactericides

An updated table for selected organic and conventional fungicides and bactericides labeled for greenhouse use will be available in Table E-11 in the upcoming 2020/2021 Mid-Atlantic Commercial Vegetable Production Recommendations Guide. The table includes an updated comprehensive list of conventional and organic fungicides and biopesticides approved for greenhouse use.

Controlling Cercospora leaf spot in beet

Cercospora leaf spot (CLS), caused by Cercospora beticola, is an important and emerging disease in beet and swiss chard production in New Jersey. Efforts to control this disease has become more difficult in the past few years in some areas of southern New Jersey. The soil-borne fungal pathogen, once established in fields, can survive in the soil for up to 2 years on infected debris and on weed hosts such as Chenopodium, goosefoot, and pigweed. The pathogen may also be seed-borne. Symptoms of infection include numerous, small tan leaf spots with distinct dark purple margins that are easily diagnosed (Fig. 1). Overhead irrigation and rainfall help spread the pathogen throughout the field.  Cercospora beticola is most damaging in warm weather (day temperature of 77 to 90° F and night temperature above 60° F).

Controlling Cercospora leaf spot with preventative fungicide applications has become challenging for some growers in New Jersey. The pathogen is known to have developed resistance to important fungicide classes in recent years, such as the QoIs (FRAC code 11) and the DMIs (FRAC code 3) in different regions of the country, based on fungicide use. This is not surprising since resistance development can occur when fungicides in these groups are used extensively over many years. In New Jersey, azoxystrobin has been used extensively for years to manage this disease.

Cultural practices to help mitigate losses to Cercospora leaf spot

There are a number of cultural practices growers can do to help reduce losses to CLS.

  • Start with certified, disease-free seed, or treat seed using hot water seed treatment method.
  • Avoid fields with a known history of CLS.
  • Rotate to non-host crops (outside of the Chenopodium family) for 2-3 years.
  • Bury infected crop residues and destroy volunteer plants and weed hosts.
  • Burn down fields after harvesting.
  • Avoid planting succession crops close together (at least 100 meters apart).
  • Avoid overhead irrigation if it will result in prolonged leaf wetness periods (e.g., late evening or at night); irrigate early to mid-day when leaves will dry fully or use drip irrigation for small plantings.
  • Using the proper fungicides, rates, and fungicide rotations.

Fungicides for controlling Cercospora leaf spot

In recent years a number of new fungicides have been labeled for CLS control. Many of these fungicides contain two different active ingredients with more than one mode of action. Growers who have relied on managing CLS with azoxystrobin (FRAC code 11) for years and suspect a loss in efficacy should consider removing it from their fungicide program. There is a good chance fungicide resistance has developed. In 2019, a field study was done at RAREC to examine the efficacy of different fungicides for CLS control (Table 1). The fungicide efficacy trial was established in field with a  history of CLS; where the field was inoculated with infected debris collected from a farm in southern New Jersey. Fungicides were applied weekly for 5 weeks with overhead irrigation to help promote disease development.

Fungicide program (application timing) FRAC code active ingredient(s) Rate per acre Labeled for beet AUDPC value
Untreated control n/a n/a n/a n/a 617 a
Kocide 3000 (1-5) M01 copper hydroxide 1.0 lb Yes 564 ab
Quadris 2.08F (1-5) 11 azoxystrobin 15.5 fl oz Yes 538 bc
Fontelis 1.67SC (1-5) 7 penthiopyrad 30.0 fl oz Yes 510 bcd
Miravis Prime 3.34SC (1-5) 7 + 12 pydiflumetofen + fludioxonil 13.4 fl oz Yes 497 bcd
Merivon 2.09SC (1-5) 7 + 11 fluxapyroxad + pyraclostrobin 5.5 fl oz Yes 471 cd
Tilt 3.6EC (1-5) 3 propiconazole 4.0 fl oz Yes 445 d

 

Cercospora leaf spot development was extremely high during the course of the study. Area Under Disease Progress Curves (AUDPC) were calculated to determine the amount of disease development under each fungicide program (Table 1). CLS development was highest in the untreated control (UTC), with no significant differences between the UTC and weekly copper applications suggesting that weekly copper applications did not help reduce CLS in this study (Table 1). Weekly applications of Quadris, Fontelis, Miravis Prime were not significantly different, but significantly lower than the UTC (Table 1). Control of CLS was best with weekly applications of Tilt and Merivon, but these were not significantly different from weekly applications of Miravis Prime or Fontelis (Table 1). Results of this study suggest that growers with resistance concerns who have relied heavily on copper and azoxystrobin for CLS control should consider using other fungicides in their weekly preventative fungicide programs. Control programs should focus on applying fungicides with more than one mode of action and focus on rotating fungicides with different modes of action. For example: (please see 2020/2021 Commercial Vegetable Production Guide), Apply Tilt (FRAC code 3) followed by Miravis Prime (7 + 12), then tebuconazole (3), then Merivon (7+ 11), then Tilt (FRAC code 3), then Luna Tranquilty (7 + 9). Remember, resistance development to FRAC code 11 fungicides (QoIs) is qualitative and controlled by single point mutations, once resistance develops the fungus is completely resistance (to all fungicides in the group). Resistance development in FRAC code 3 fungicides (DMIs) is quantitative which often characterized as a gradual loss of resistance over time. As a note, FRAC code 3 fungicides should always be applied at the highest rate, using lower rates may increase selection pressure.

Organic Control Options

Controlling CLS in organic production systems starts by following and executing good cultural practices listed above. Always purchase certified seed. Use the hot water seed treatment method to help disinfested seed. Avoiding fields with a history of the disease. Producing beet on mulch and drip irrigation in small operations should be considered. This will help reduce weed pressure (as well as potential hosts) and reduce the need for overhead irrigation. Organic copper applications may not be effective in some operations where disease pressure is extremely high. Unfortunately, control of CLS with organic and biopesticides has been difficult, therefore good cultural practices must be followed accordingly.

 

Understanding and Controlling Tomato Brown Rugose Fruit Virus

Tomato Brown Rugose Fruit Virus (ToBRFV) is an emerging virus in greenhouse tomato production worldwide. The virus was first identified in Israel a few years ago and has since been found in Europe, Asia, Mexico, and the US.  The pathogen is known to be present in greenhouse tomatoes in Mexico, and has occasionally been found in field tomatoes grown there (UMASS); it has also been found on imported fruit in FL (Also see VGN story below). An outbreak was reported (and contained) in CA in early 2019 but, unfortunately, the virus was found in greenhouse tomato production in New Jersey this past fall.

ToBRFV is more severe on young tomato plants and can result in 30-70% yield loss (UFL). Foliar symptoms of ToBRFV on tomato and pepper include deformed, crinkled leaves, mosaic, mottling, flecking, chlorosis, and/or necrosis (see images). Fruit symptoms include discoloration and rough brown patches or ringspots. Irregular fruit shape and maturation patterns may also occur. Browning of the veins in the fruit calyx in the early stages of fruit ripening may also be observed. Symptom expression can vary widely among tomato cultivars (UMASS); while some green fruit may be infected but remain asymptomatic until the fruit starts to ripen.

ToBRFV is a member of the tobamovirus family along with tobacco mosaic (TMV), tomato mosaic (ToMV), and tomato mottle mosaic (ToMMV). ToBRFV is especially worrisome for tomato growers because it has overcome the Tm-22 gene that confers resistance to tobamoviruses in many tomato cultivars. Like TMV, ToBRFV is very stable and easily transmitted by mechanical means; in a highly managed crop such as greenhouse tomatoes, this means that human activity is the primary vector. The virus may also be transmitted mechanically by bumble bees employed to pollinate greenhouse crops. The virus can be seedborne and research indicates that it is associated with the seed coat, not the embryo. This means that treatments such as hot water or steam should be effective in removing the virus from seed (UMASS).

Management practices for ToBRFV include planting of disease free seed and seedlings, scouting plants regularly for symptoms, and isolating symptomatic plants. Disinfect tools and workers’ hands frequently. Recent research has demonstrated that the most effective disinfectants include 10% bleach, 50% Lysol, and 20% nonfat dry milk (UMASS). Currently, no commercial tomato varieties are tolerant to ToBRFV. Peppers with tolerance to TMV and pepper mild mottle virus (PMMoV) have shown some tolerance (MSU). ToBRFV’s high stability allows it to stay infectious in the soil, in plant debris and on stakes for long periods—up to 20 years. There are reports of spread by bumble bee pollinators in greenhouse situations. However, there are no reports of plant-to-plant transmission by aphids, leafhoppers or white flies (MSU).

There are no sprays that can be applied that are effective in helping to reduce the virus’s spread. Seed and transplant production are the most critical steps since contamination at these steps may create a risk of further contamination (MSU). A number of County Offices have the equipment for doing the hot water seed treatment method. Please contact your county agent for more information. Importantly, as a note, there is very limited to no information on infested seed sources, with only a few greenhouse tomato cultivars with known problems.

Recommended actions include (from MSU):

  • Start with certified clean or treated seed from a reputable dealer. Do not purchase seed from unverified sources, especially if they come from known restricted areas.
  • Have greenhouse workers wash and sterilize hands and tools often.
  • Supply single-use gloves that are discarded between greenhouse ranges.
  • Provide protective clothing that stays in that greenhouse range or that is well washed before going to another range.
  • Dispose of symptomatic plants and plants within 5 feet of infected plants. Also, dispose of plants, strings, trays and media through incineration—DO NOT spread it out on your fields (or reuse it for other crops in the greenhouse)!
  • Monitor movement of equipment and workers between fields. Thoroughly wash equipment and possibly have workers bring a change of clothes.
  • Rogue and incinerate symptomatic plants and conduct any daily activity last in that greenhouse followed by good sanitation.

On November 15, 2019, USDA/APHIS issued an emergency federal order that calls for pre-export testing of tomato and pepper propagative material (plants, seeds, grafts, and cuttings) and fruit produced in any country where ToBRFV has been detected; to date, this list includes Israel, Jordan, Turkey, Greece, Italy, the United Kingdom, the Netherlands, China, and Mexico. Countries where ToBRFV has not been reported may state this fact by providing a letter from the nation’s plant protection organization: propagative material and fruit exported to the USA will then be exempt from the testing requirement. Tomato and pepper fruit from Canada will also be subject to inspection prior to export, because Canada imports these crops from Mexico and re-exports them to the US. US Customs and Border Protection will also increase inspections at U.S. ports of entry to ensure imported tomato and pepper fruit from Mexico, Israel, the Netherlands, and Canada are free from symptoms of ToBRFV. (UMASS, USDA)

The NJDA, in cooperation with USDA APHIS PPQ, has been assisting affected NJ tomato producers in identifying critical control points and implementing the best management practices necessary to reduce the threat of introducing Tomato Brown Rugose Fruit Virus (ToBRFV) into future production. Tomato growers in New Jersey who suspect ToBRFV are encouraged to contact their county agent and the NJDA Division of Plant Industry. The NJDA is working with USDA APHIS PPQ to establishing testing protocols and will facilitate the screening of suspect plants.

References:

Dr. Anglela Madeiras (UMass)

http://ag.umass.edu/greenhouse-floriculture/fact-sheets/tomato-brown-rugose-fruit-virus-tobrfv

Dr. Ron Goldy (Michigan State University)

https://www.canr.msu.edu/news/tobrfv-a-new-concern-for-tomato-and-pepper-producers

Kendall Stacy (University of Florida)

http://blogs.ifas.ufl.edu/pestalert/2019/07/23/tomato-brown-rugose-fruit-virus/

American Seed Trade Association

https://www.betterseed.org/wp-content/uploads/ToBRFV-QA.pdf

USDA/APHIS

https://www.aphis.usda.gov/aphis/newsroom/stakeholder-info/sa_by_date/2019/sa-11/tomato-brown-rugose-fruit-virus

Vegetable Grower News – Tomato Brown Rugose Virus Concerns Growers

Hackettstown Livestock Auction Results for November 11, 2019

This auction sells: lambs, sheep, goats, calves, beef cattle, pigs, rabbits, and all types of heavy fowl. Auctions are held every Tuesday with the first sale beginning at 10:30 am and ending with the last sale at 5:30 pm. Hay, straw, grain, and firewood are also for sale.

Hackettstown Livestock Auction

Farm Fresh Eggs available for purchase by the case (30 doz.) or by the flat (2&1/2 doz.) in the main office Tuesday, Wednesday & Thursday. Also available some Monday’s and Friday’s but please call office first (908)-852-0444.

Click on link for November 11, 2019 sale results:

Hackettstown 11-19-19

 

Evaluating postharvest cleaners, sanitizers, and surfaces

Soapy countertopGAPs, third-party audits, and the FSMA Produce Safety Rule have a heavy focus on the cleaning and sanitation of surfaces that come in contact with produce. These surfaces can be harborage points for pathogens that are problematic for those that consume them, and for decay organisms that shorten your crops shelf life and marketability.

During the summer of 2019 we gathered a number of surface materials that are commonly used in packing houses, some of the surfaces are used as temporary fixes, others are for permanent use. Each of the surfaces was evaluated for cleanability and sanitation using common detergents and sanitizers. Swab sampling was used to assess “dirtiness” before cleaning, and then cleanliness after rinsing with water, after using a detergent, and again after using a sanitizer. We paid attention to how quickly the swab sampling numbers were reduced after each step.

What was abundantly clear was that the process is critical, no matter what detergent or sanitizer you use. The most effective process is:
1. Rinse all visible debris off of the surface with water
2. Use an appropriate detergent and scrub the surface, paying attention to all corners, crevices, joints, and screw/bolt heads
3. Rinsing the surface clear of detergent and dislodged debris
4. Use a sanitizer approved for food contact surfaces, follow the directions

Another common issue found was that visibly clean doesn’t necessarily mean that the surface is clean enough to use. Just rinsing off with water can remove visible debris, and reduced the swab sampling number, but not enough to be considered clean. This was consistent across all the surfaces we evaluated in the study.  Surfaces evaluated included vinyl flooring, polyvinyl chloride (PVC), polypropylene (PP) surfaces, high density polyethylene (HDPE) tabletop, fiberglass reinforced panels (FRP), acrylic sheet (PPMA), styrene, extruded composite lumber (PET), wood surfaces, plastic household mats, and sheet metal painted with countertop paint. These surfaces were chosen for their ease of purchase locally and that many have been seen in use on farms across the state.

There are many sanitizers available on the market, including organic approved products. We evaluated chlorine, peroxyacetic acid, quaternary ammonium, and chlorine dioxide. All are labeled for use on food contact surfaces. Label instructions were followed and dip strips were used to ensure that the target PPM of each sanitizer was achieved. Using too little of a sanitizer is ineffective, and too much of a sanitizer can cause damage to the surface you are cleaning. Detergents evaluated were common dishwashing detergent, citric acid, ethoxylated coconut oil, and a foaming non-hazardous spray on detergent.

When the swab sampling numbers were evaluated we found that smooth surfaces cleaned the best and were more consistently sanitized. Surfaces with raised designs, grooves, or bumps did not have as significant reduction of swab sampling numbers as compared to the smooth surfaces. This inability to sanitize as effectively can allow for biofilms to form, providing a harborage point for disease. The surfaces that were most consistent in their ability to be cleaned and sanitized were fiberglass reinforced panels, commonly known as sanitary wall and often used in dairy milk houses, and extruded composite lumber. Surfaces painted with countertop paint did well initially, but repeated scrubbing allowed for scratches in the paint, and thinning of the surface over time. This resulted in a reduced ability to clean and sanitize effectively. Surfaces that consistently showed they were uncleanable were foil tape (sometimes used as a quick fix on surfaces), flexible plastic kitchen mats, uncoated wood surfaces, and vinyl flooring. All other evaluated surfaces had variations in the swab analysis results based on the detergent and sanitizer combinations. All detergents were effective at reducing the swab sampling numbers, with the foaming detergent having a more consistent effect over all of the surfaces tested. The sanitizers evaluated, when used according to product directions and on smooth surfaces, reduced the swab sampling numbers significantly.

Critical points to consider:

-Develop a regular cleaning schedule with a written standard operating procedure detailing the products used, how they are used, and the steps involved in cleaning and sanitizing the surfaces.
-Do a test run when you aren’t pressed for time, take apart equipment, determine if you have the right supplies, and estimate the time it will take to properly clean and sanitize the equipment.
-Remember that the beginning of the season cleaning and sanitizing procedure will likely be more detailed than a during the season cleaning.
-Provide training for the person/s, and their backup, who will be responsible for cleaning and sanitizing postharvest surfaces.
-Only use sanitizers that are approved for food contact surfaces, and follow the label directions.
-When fixing packing equipment only use surfaces that are smooth, do not absorb water, and have not been used for other activities at the farm that may pose a contamination risk.
-Avoid cracks and crevices on your postharvest surfaces, these are difficult to clean and sanitize.
-When gloves are used workers must be trained on how to use them so they do not become a contamination source.
-Remove surface moisture in the packinghouse/area whenever possible using squeegees and fans.
-Remove culls from the packing area daily so they do not become an attractant for wildlife.
-Utilize a pest control program in the packing and storage areas, focusing on rodents and other wildlife intrusions.
-Remove as much soil as possible from harvested produce in the field, rather than in the packing area.
-Use new containers or containers that can be cleaned and/or sanitized to pack and display produce.
-Storage areas and coolers should be monitored for cleanliness, and be included in the rodent control program.

Visit the Rutgers On-Farm Food Safety website for more produce safety resources.

 

This work funded by USDA Specialty Crop Block Grant #16-SCBGP-NJ-0046

6-Week Urban “Annie’s Project” Farm Management & Business Training Course

Especially aimed at NJ farm women and veterans, Rutgers Cooperative Extension (RCE) will present a new, urban-focused version of the popular Annie’s Project titled “Farming in New Jersey’s Cities and the Urban Fringe.” Classes will be held simultaneously in Roseland, New Brunswick and Cherry Hill on Dec. 3, 10, 17 and Jan. 7, 14, 21, between the hours 6 – 9 p.m. Registration is currently open and is $150 until Dec. 2. Dinner will be provided at 5pm each evening of the class. [Read more…]