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.
 
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Rutgers Weather Forecasting - Meteorological Information important to commercial agriculture.

U-Pick Operation Guidelines under COVID-19

Harvesting cropsThe CDC, FDA and USDA have no reports at this time of human illnesses that suggest coronavirus can be transmitted by food or food packaging.
U-Pick operations are unique with customers going out into the field to do their own harvesting. This creates special situations for the grower and customer. How do you protect the customers, workers, and grower?

Questions to Ask Yourself
1. How many customers will you allow to pick at one time and how will you manage this?
2. Will you provide picking containers, or do you expect the customer to bring their own?
3. Will you provide harvest tools, or do you expect the customer to bring their own?
4. Where are your handwashing facilities located? Do you need to add more or change the locations?
5. How will you provide produce to those who are unable to enter your retail area or conduct U-Pick activities?
6. What areas will need frequent cleaning and sanitation (PDF)? What products will you use for this task?

Customer Notification Prior to Arriving
1. Use your social media site to inform potential customers how you are going to run your U-Pick operation with COVID-19.
2. Inform customers that they must maintain 6 ft social distance from other customers and employees.
3. Let them know that handwashing stations and hand sanitizers will be available when they arrive.
4. Encourage your customers to come alone. Leave family at home. Only someone picking should be in the field.
5. Let them know if you will provide picking containers or they need to bring their own.
6. Face coverings are required for customers. If a customer arrives without one, or refuses to wear one, they cannot enter retail and production areas. Alternative methods of obtaining produce should be made available to them.

Upon Customer Arrival
1. Encourage everyone to wash their hands prior to going into the field.
2. Inform customers where they can pick and how many people are allowed in the field at one time.
3. Direct customers to wear face coverings and to practice social distancing.

Handwashing
1. Have handwashing stations at several locations on the farm. These should be conveniently located. If the field is not next to the check out area have handwashing stations out in the field.
2. Everyone should wash their hands often for 20 seconds with soap and water.
3. This means as soon as customers come to the farm, if they stop to eat, when they use bathroom facilities, etc. If hand sanitizers are available customers should wash hands then apply hand sanitizers. The sanitizer should be at least 62% alcohol.
4. Post handwashing signage (PDF) in the appropriate language at each handwashing station.
5. Designate the responsibility of monitoring handwashing facility supplies (water, soap, paper towels) to an individual. Provide ample supplies for restocking.

Field Picking
1. There different ways to handle picking. The number of pickers can be restricted at any one time or pick every other row. Whichever system is used there needs to be someone in the field to enforce the rules.
2. Consider what you supply to the customer when they go into the U-Pick areas.
3. Harvest tools, containers, wagons, etc. Ensure that you can properly clean and sanitize these commonly touched surfaces.

Employees
1. Train all employees on proper handwashing and food safety.
2. In New Jersey, employers must provide face coverings and gloves for their employees.
3. Handwashing is critical when dealing with customers (see above).
4. Hand sanitizers should be used between each customer by employees at checkout.
5. Touchpads should be sanitized between payment uses.
6. One person should handle money when checking out customers.

Visit the Rutgers On-Farm Food Safety and the Rutgers NJAES COVID-19 websites for the most up-to-date information.

Authors
Wesley Kline, Agricultural Agent, Rutgers Cooperative Extension of Cumberland County
Jennifer Matthews, Senior Program Coordinator, Rutgers Cooperative Extension of Cumberland County
Meredith Melendez, Agricultural Agent, Rutgers Cooperative Extension of Mercer County

Understanding phenylamide (FRAC group 4) fungicides

The phenylamide fungicides (FRAC group 4) are a highly active class of fungicides that target oomycete pathogens such Phytophthora and Pythium spp. FRAC group 4 fungicides are also highly effective against downy mildew pathogens such as Pseudoperonospora cubensis (cucurbit downy mildew), Phytophthora infestans (Late blight), and basil downy mildew (Peronospora belbahrii) and many other important pathogens in vegetable production. Like other fungicide classes, FRAC group 4 fungicides have a high-risk for fungicide resistance development. The phenylamides (PA) inhibit ribosomal RNA (rRNA) biosynthesis in oomycete pathogens which inhibits several life stages in oomycetes including hyphal growth, haustoria and sporangia formation. The exact mechanism for resistance is not completely understood although research has shown that PA resistance is control by a single incompletely dominant gene although multiple mutations or mechanisms may be involved in PA resistance development. Pathogens such as cucurbit downy mildew, late blight, and basil downy mildew can be disseminated over vast geographic distances in any given year, thus this migration can be responsible for the introduction of new pathogen genotypes (including PA resistant) to new locations along with local selection pressure due to PA fungicide use resulting in changes in the pathogen population. Additionally, pathogens such as P. infestans and P. capsici (Phytophthora blight) are highly sexually active at the local level, because of the potential presence of two mating types (A1 and A2), you have a “recipe” that is always evolving. Resistance development to PA fungicides is often described as sensitive, intermediate, or resistant based on EC50  (Effective Concentration) values of the different fungicides needed to kill 50% of the pathogen in laboratory assays. This type of collected information is useful in determining what proportion of a given local, or wide geographic pathogen population, may be PA resistant. Recommended resistance management guidelines developed FRAC have not changed since 1997and are intended as general recommendations that must be adapted to respective pathosystems, fungicide use and patterns, and resistance levels.

The following are general recommendations for PA fungicide use as stated by FRAC.

  • PA fungicide should be used on a preventative basis; and not used as a curative or on a eradicative basis
  • As foliar applications, PA fungicide should always be tank mix with a unrelated fungicide from a different FRAC group
  • The total number of PA applications per season should be limited to 2 to 4 depending on label requirements
  • PA sprays are recommended for use earlier in the production season during active vegetative growth
  • PA should not be used as soil treatments against foliar disease development

Resistance development in P. capsici to mefenoxam has been known for many years in southern New Jersey. This is most likely to the widescale and overuse of mefenoxam in its early days because of the lack of an alternative chemistry, as well as a result of crop rotations where susceptible crops were planted in the same field for many years. In the past decade, there have been several new fungicides from different FRAC groups labeled for oomycete control. These include: Orondis Gold (oxathiapiprolin + mefenoxam, FRAC groups 49 + 4), Previcur Flex (propamocarb, 28), Ranman (cyazofamid, 21), Presidio (fluopicolide, 43), and Phosphites (33) for field use. Ranman, Previcur Flex, and phosphites have greenhouse use labels for Pythium control. Ranman and Previcur Flex can be applied in the transplant water.  Orondis Gold, mefenoxam, metalaxyl, and the phosphites are the most systemic of the group and should readily be taken up the by plant via application through the drip. Presidio has locally systemic and translaminar activity and offers protection of the root system via drip. Ranman has protectant-like activity and thus will offer root system protection. Growers with a known history of mefenoxam-insensitivity on their farm should use Presidio, Previcur Flex, or Ranman plus a Phosphite fungicide in rotation in their drip application programs. Importantly, if mefenoxam has not been used in particular fields on any crop for a number of years (more than 5+) the fungus may revert back to being mefenoxam-sensitive and control with these products may return.

For more information please see specific fungicide labels, crops sections, and greenhouse uses in Table E-11 in the 2020/2021 Mid-Atlantic Commercial Vegetable Production Recommendations Guide.

Reference:

Hermann, D.C., McKenzie, D., Cohen, Y., and Gisi, U. 2019. Phenylamides: Market trends for resistance evolution for important oomycete pathogens more than 35 years after product introduction (FRAC code 4). Chapter 6 in: Fungicide Resistance in North America, 2nd Ed. Katherine L. Stevenson, Margaret T. McGrath, and Christian A. Wyenandt (eds). The American Phytopathological Society, St. Paul, MN.

Additional resources:

Damping-off: Identifying and Controlling Early-Season Damping-off Pathogens

Understanding Damping-off Pathogens During Seeding and Transplanting

UPDATE: Paraquat Training for Certified Applicators NOW AVAILABLE IN SPANISH

The EPA-approved paraquat certified applicator training online module was released in Spanish yesterday. Training in either English or Spanish accessible at the link provided on paraquat product labels or http://www.usparaquattraining.com/.  You will be prompted to create a user account to take the training. Upon successful completion of the training, your online account can be accessed anytime to […]

Understanding the SDHI (FRAC group 7) Fungicides

The SDHI (succinate dehydrogenase inhibitor) fungicides belong to FRAC group 7 which have been on the market since the late 1960s. Third generation SDHIs have been available since 2003 with release of boscalid (penthiopyrad). Examples of FRAC group 7 fungicides used to control important vegetable diseases include: flutolanil ( year introduced,1986), boscalid (2003), penthiopyrad (2008), fluxapyroxad (2011), fluopyram (2013), and pydiflumetofen (2016). All fungicides in FRAC group 7 inhibit complex II of the fungal mitochondrial respiration by binding and blocking SDH-mediated electron transfer from succinate to ubiquinone. The SDHI fungicides work much like the FRAC group 11 fungicides, just at a different site in mitochondrial respiration. Much like FRAC group 11 fungicides, they are also at-risk for fungicide resistance development because of their specific modes of action. Research has shown there are numerous single point mutations that can lead to resistance development to FRAC group 7 fungicides. Although all SDHI fungicides share the same target site, sensitivity to the different fungicides within the FRAC group may vary. Thus, this variation in sensitivity among different SDHI fungicides leads to confusion on what the term “cross-resistance” means. With cross-resistance, once a pathogen develops resistance to one fungicide within the FRAC group, it becomes resistant to all others (e.g., strobilurin resistance in FRAC group 11 fungicides). However, in FRAC group 7 fungicides, there seems to be differences in sensitivity between fungicides within the group after resistance has been detected in one particular fungicide. The good news is that other FRAC group 7 fungicides may retain there efficacy even if resistance is detected in one particular fungicide. “The practical implications for resistance management would be the recommendation of mixtures of SDHIs, alternations of SDHIs, or even the substitution of members of the SDHI fungicide class. However, this would be counterproductive in protecting this mode of action.” (Klappach and Stammler, 2019). The important point, switching exclusively to another SDHI fungicide after resistance has been found in one is not a good resistance management strategy. As with all fungicide resistance management strategies, growers should focus on rotating as many different FRAC groups into their fungicide programs as possible, and limit the total amount of any one FRAC group during the production season.

Additional resources:

Theories on tank mixing and rotating fungicides in different FRAC groups

Understanding protectant fungicides

Understanding FRAC group 3 and 11 fungicides

Produce Blue Book Shares USDA CARES Buy-Fresh Has Short Deadlines

USDA provides more details about the Buy Fresh program and a link to its solicitation page here.

USDA’s Buy Fresh program has tight deadlines

USDA Announces Coronavirus Food Assistance Program

From usda.gov/media/press-releases on April 17, U.S. Secretary of Agriculture Sonny Perdue announced the Coronavirus Food Assistance Program (CFAP).

“The program will provide $16 billion in direct support based on actual losses for agricultural producers where prices and market supply chains have been impacted…” including $9.5 billion in aid to cattle, dairy and hog farmers, $3.9B to row/commodity crops, $2.1B for specialty crops growers, and $500 mil for “other” crops ($500 million).

The remaining $3B will be used to increase purchases of fresh produce, dairy, and meat to be distributed through “food banks, community and faith based organizations, and other non-profits serving Americans in need.”

More details about the CFAP can be found in the press release, however, as of yesterday morning, local USDA Service Centers had not yet received directions on how/where/when farmers should apply for direct assistance. They will inform local farmers as soon as the information becomes available and we will also pass on that information as soon as we have it.