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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NJ Commercial Vegetable Production Recommendations
Rutgers Weather Forecasting - Meteorological Information important to commercial agriculture.
NJDEP Notice: Delayed Processing of Applications and Other Requests Due to July COVID-19 Furloughs
RCE Agents Offer Marketing Tips With Del State U & USDA Northeast Climate Hub
Webinar Postponed ’til Fall!
Due to technical issues and low enrollment, this webinar has been postponed by the organizers and will be rescheduled for the fall.
Register here today (7/7/20) by 11pm!
Webinar: Part 2 in a series
Emergency Preparation & Dealing with COVID-19 on Farms: Alternative Marketing Strategies to Stay in Business
Wednesday, July 8, 2020
Time: 12 – 1:15 PM
Use the link below to register by July 7, 2020, 11 PM EST. The Zoom link to the webinar will be e-mailed to all registered attendees prior to the webinar.
[link removed]
Small farmers and extension agents working with small farmers will learn best practices for communicating with consumers and meeting their demands.
Participants will learn how to:
- Use available resources to market your products
- Reach out to consumers online
- Use alternative marketing strategies to sustain and grow businesses
- Use online business opportunities for farm sales
Attendees will learn about available resources to help them manage logistics of the Covid-19 health crisis on their farms. Presenters will share information and solutions from the experts and answer questions from participants. Like the first webinar in this series, this meeting will address common problems most farmers are facing, what they are planning to do to stay in business and how well their plans are working. The webinar series also summarizes how extension programs can assist farmers through this difficult time.
Agenda (Q&A session after each presentation)
| 12 – 12:05 PM | Welcome & Introduction | Gulnihal Ozbay & Jason Challandes, DSU; Erin Lane, USDA Northeast Climate HUB |
| 12:05 – 12:25 PM | “Know Your Customers Know Your Prices” |
Richard VanVranken, Professor & County Extension Department Head (Small Farms & Farm Marketing), Rutgers Cooperative Extension of Atlantic County, New Jersey |
| 12:25 – 12:45 PM | “Meeting Customer Demands for Agricultural Products In response to the Covid-19 Pandemic” |
Stephen Komar, Associate Professor & Agriculture & Natural Resources County Agent II, County Extension Department Head (Plant and Animal Agriculture), Rutgers Cooperative Extension of Sussex County, New Jersey |
| 12:45 – 1:05 PM | “Online logistics and considerations with Direct Sales Models during Covid-19” | William J. Bamka, Associate Professor & Agriculture & Natural Resources County Agent II, County Extension Department Head of Rutgers Cooperative Extension of Burlington County in New Jersey, Crop Production and Agritourism |
| 1:05 – 1:15 PM | Closing Remarks & Information on Webinar Evaluation |
Dr. Ozbay and Ms. Lane |
This webinar series is moderated by Delaware State University Cooperative Extension (Dr. Gulnihal Ozbay) & USDA Northeast Climate Hub (Erin Lane). Webinar hosts are Ms. Megan Pleasanton & Mr. Jason Challandes (DSU Cooperative Extension).
Cucurbit Downy Mildew Alert – 7/6/20
Cucurbit downy mildew (CDM) has been reported on cucumber in southern New Jersey (Salem County). This is the first report of CDM this growing season in the state. All cucumber and cantaloupe growers are encouraged to scout fields on a daily basis and begin preventative CDM fungicide programs if already not initiated. Presently, there is no need to initiate spray programs on other cucurbit crops in New Jersey.
For up-to-date information on CDM and its control please click here.
To track the progress of CDM in the US please click here.
Governor Signs Permit Extension Act: NJDEP Water Certifications Extended 1 Year
Governor Murphy signed The Permit Extension Act (A3919/S2346) this week, which extends certain permits during the COVID-19 emergency. Agricultural Certifications issued by the DEP are included in this extension, so any Agricultural Certification which expired on or after March 9, 2020 will be extended.
Any complete new, renewal or modification application already submitted to the DEP will continue to be reviewed and issued for the full five-year term.
Any Certification holder who received the first renewal reminder which contained the pre-filled application form does not need to do anything at this time. The DEP will forward you a new pre-filled application once the extension period is over.
“COVID-19 extension period” means the period beginning March 9, 2020 and continuing for as long as a public health emergency, pursuant to the “Emergency Health Powers Act,” P.L.2005, c.222 (C.26:13-1 et seq.), or a state of emergency, pursuant to P.L.1942, c. 251 (C.App.A.9-33 et seq.), or both, that has been declared by the Governor in response to COVID-19, is in effect.
Please be advised that annual water diversion reports were required to be submitted to the DEP by February 28, 2020 and are not extended due to the passage of this Bill. The DEP is issuing reminders to those who failed to submit this information in accordance with their Certification. Continue to log diversion amounts and submit your reports in accordance with the deadlines in your Certification.
Rutgers Cooperative Extension is working very closely with the DEP’s Bureau of Water Allocation & Well Permitting to resolve any ongoing issues and concerns. The Bureau is aware that many renewal applications are awaiting the Ag Agent review and signature. With the extension act, these renewal applications are being extended as mentioned above.
Some RCE Offices remain closed or with minimal access at this time. Call your local Rutgers Cooperative Extension office for specific information. In addition, during the month of July, staff in the NJ Department of Agriculture and the NJ DEP personnel are furloughed, and response times will be slowed, so please be patient during these challenging times.
Update on cucurbit downy mildew and its control
Cucurbit downy mildew (CDM) has been confirmed on cucumber in southern New Jersey; in southwest and southeast Michigan this past week and as far north as Edgecombe County in northern North Carolina this week; and on watermelon and cantaloupe as far north as southern South Carolina this growing season. This is the first report of CDM in the mid-Atlantic region this growing season For those growers in the region this means there are two geographic areas where CDM may be coming into the region, from the west and from the south.
In 2004, cucurbit downy mildew re-emerged in the US with a vengeance causing significant losses in cucurbit production. In most years prior to this, concern for CDM control was minimal, since the pathogen arrived late in the growing season (in more northern regions), or the pathogen caused little damage, or never appeared. After 2004, with significant losses at stake, and with very few fungicides labeled for its proper control, CDM became a serious threat to cucurbit production. Importantly, at the time, cucumber varieties with very good levels of CDM resistance were no longer resistant, suggesting a major shift in the pathogen population. Research done over the past 15 years has led to a better understanding of the pathogen. Recent research has determined that the CDM falls into two separate clades: Clade I and Clade II. Some CDM (Pseudoperonospora cubensis) isolates fall into Clade I which predominately infect watermelon, pumpkin, and squash, where CDM isolates in Clade II predominately infect cucumber and cantaloupe. Research suggests that isolates in Clade II can quickly become resistant to specific fungicides (NCSU). Most cucumber varieties are resistant to Clade 1 isolates, but there is no resistance currently available for Clade 2 isolates. For pickling cucumber the varieties, Citadel and Peacemaker, are tolerant to clade 2 isolates. For slicing cucumbers, the varieties SV3462CS and SV4142CL are tolerant to Clade 2 isolates. All organic and greenhouse growers are encouraged to use tolerant varieties since chemical control options are very limited (NCSU). An extended list of cucumber varieties with CDM resistance from the University of Florida can be found here. For the past decade, researchers from around the US have been closely monitoring and forecasting the progress of CDM through a website hosted by NCSU. The CDMpipe website is currently in the process of an upgrade and will now be hosted by Penn State University. All cucurbit growers are encouraged to sign up to the CDMpipe website to help them know what cucurbit crops are being infected (and where) and to follow the forecasting to know where the pathogen may move to next. As a note, in recent years, CDM control with certain fungicides has varied significantly depending on the cucurbit host and geographic region. This is extremely important since two clades of the pathogen are potentially present (affecting host range) as well as having a potential impact on control strategies. How do you know which clade may be present on your farm? Follow the reports. If CDM is mostly present in cucumber crops as it works its way up the east coast, then you are most likely to see it infect cucumber and cantaloupe on your farm first. Scout your fields regularly, especially if CDM is in the immediate region. Pay very close attention to symptom development and on what cucurbit crop(s) you see it on, this is especially important if you grow more than one cucurbit crop. Like cucurbit powdery mildew, once CDM arrives in the region preventative fungicide applications are necessary.
Fungicides for CDM control
Loss of efficacy in the control of CDM has also been documented in FRAC code 4 (mefenoxam), FRAC code 11 fungicides (azoxystrobin), FRAC code 28 (propamocarb HCL), and FRAC code 43 (fluopicolide) in the mid-Atlantic region and elsewhere. Insensitivity to fluopicolide (43) and propamocarb HCL (28) have been reported in multiple states (Thomas et al., 2018). In some cases, individual isolates of CDM were insensitive to both chemistries. Recent research in Michigan in a three year field study using pickling cucumber determined that cyazofamid (21), (ametoctradin, 45 + dimethomorph, 40), (zoxamide, 22 + mancozeb, M03), mancozeb (M03); chlorothalonil (M05), and oxathiapiprolin (49) alone or in a premix provided the best level of control (Goldenhar & Hausbeck, 2019). In a recent study evaluating different fungicide chemistries in field trials done in different states (OH, NY, & SC) determined that propamocarb HCL (28), cymoxanil + famoxadone (27 + 11), and fluopicolide (43) were ineffective in 1 or 2 states during both years of the trial (Keinath, Miller, & Smart, 2019). In one year of the study, famoxadone (11), dimethomorph (40), cymoxanil (21), and mancozeb (M03) were ineffective for CDM control (Keinath, Miller, & Smart, 2019). In bioassay studies done during this trial, cyazofamid (21), oxathiapiprolin (49) suppressed CDM >80%.
Most fungicides labeled for the control of CDM are at-risk for resistance development because of the specific modes of action. These include Ranman (cyazofamid, FRAC code 21), Gavel (zoxamide, 22 + mancozeb, M03), Zing! (zoxamide, 22 + chlorothalonil, M05); Curzate (cymoxanil, 27), Previcur Flex (propamocarb HCL, 28), Forum/Revus (dimethomorph, 40), Zampro (ametoctradin, 45 + dimethomorph, 40), Orondis Opti (oxathiapiprolin, 49 + chlorothalonil, M05), and Orondis Ultra (oxathiapiprolin, 49 + mandipropamid, 40). Importantly, just like with cucurbit powdery mildew control, there are a number of CDM fungicides with different modes of action from different FRAC codes to chose from. As noted in the paragraph above, the efficacy of individual fungicide chemistries may vary significantly by state or region. Thus, growers need to scout their cucurbit fields on a weekly basis, note the efficacy, or lack thereof, they are seeing in the field, and incorporate the use of as many different FRAC groups as possible to help mitigate fungicide resistance development.
Fungicide programs for CDM control
An example of a fungicide program for CDM control in the mid-Atlantic region might look like this, where a CDM specific fungicide from a different FRAC group is used on weekly basis:
A – B – C – D – E
where A= Gavel (zoxamide, 22 + mancozeb, M03); B= Orondis Opti (oxathiapiprolin, 49 + chlorothalonil, M05); C= Ranman (cyazofamid, FRAC code 21); D= Orondis Ultra (oxathiapiprolin, 49 + mandipropamid, 40); E= Curzate (cymoxanil, 27)
Not all of the fungicides listed above are labeled for all cucurbit crops. Some fungicides, such as the Orondis products have limited number of applications. Growers will need to refer to local recommendations and the label for crop specifics. Remember, the label is the law.
A protectant fungicide such as chlorothalonil or mancozeb should be added (if not already included) to the tank mix with each high-risk fungicide to reduce selection pressure and to help control other important diseases such as anthracnose and plectosporium blight. All growers should follow use recommendations on labels and avoid overusing one mode of action, even if it works well. If loss of efficacy is present, the grower should avoid using that particular fungicide (FRAC group) for CDM control the rest of the growing season.
Growers should remember that fungicides specifically labeled for CDM control won’t control CPM, and fungicides labeled for CPM control won’t control CDM. Therefore, carefully following the disease monitoring and forecasting website, choosing varieties with CDM resistance, paying close attention to host crops, scouting fields on a regular basis, noting fungicide efficacy, and following proper fungicide resistant management guidelines remain critically important for successful CDM control.
For more information on the specific fungicides recommended for CDM control on cucurbit crops please see the 2020/2021 Mid-Atlantic Commercial Vegetable Production Recommendations.
The A-B-C’s of cucurbit powdery mildew control
Cucurbit powdery mildew (CPM), caused by Podosphaera xanthii, is one the most important diseases of cucurbit crops throughout the world. The pathogen is an obligate parasite, just like cucurbit downy mildew, meaning it needs a living host in order to survive. In northern regions that have a killing frost in the fall the pathogen will die out when the crop freezes. Not being able to overwinter, the pathogen must be re-introduced each spring or summer in the mid-Atlantic region. The pathogen accomplishes this by re-infecting cucurbit crops in the spring as they are planted up the east coast starting in Florida, then the Carolina’s, Virginia, and so forth. By late May, as soon as cucurbit crops begin to germinate in the mid-Atlantic region, the potential threat for potential powdery mildew infections begin.
The first step in mitigating CPM begins with planting powdery mildew tolerant (PMT) or resistant (PMR) cultivars if they meet your needs. It is important to remember that these cultivars are not “immune” to CPM; they will become infected at some point in the growing season depending on disease pressure. Hopefully, this will occur later in the season when compared to CPM susceptible cultivars. Organic growers hoping to mitigate losses to powdery mildew should always chose CPM tolerant or resistant cucurbit cultivars first. There are a number of OMRI-approved fungicides labeled to help suppress CPM development, these should always be used in concert with CPM tolerant or resistant cultivars and a preventative fungicide program. Cultural practices such as increasing in-row plant spacing to improve air flow and cultivation to keep weeds to a minimum will also be advantageous. Avoiding the use of overhead irrigation will help reduce disease pressure from another important pathogen, cucurbit downy mildew. Thus, growing cucurbits on a mulch with drip irrigation has its advantages, but also increases costs.
In the past, a typical conventional fungicide program consisted of rotating two different FRAC group fungicides every other week, such that the pattern looked like:
A – B – A – B – A – B
Often a protectant fungicide such as chlorothalonil or mancozeb is added to the tank mix on a weekly basis to 1) help control other important fungal diseases, such as anthracnose or gummy stem blight and 2) to help reduce selection pressure on the high-risk fungicide that was being applied. This type of preventative program was used for many years, because, in most cases there were just a few effective fungicides available for CPM control depending on the crop. An example of this would be:
A = (azoxystrobin [FRAC group 11] + chlorothalonil (MO5) rotated weekly with B = (myclobutanil [FRAC group 3] + chlorothalonil (MO5)
This type of control strategy worked extremely well as long as the pathogen didn’t develop resistance to either the FRAC group 11 (azoxystrobin) or FRAC group 3 (myclobutanil) fungicide. To better understand modes of action and how fungicide resistance develops in FRAC group 11 and FRAC group 3 fungicides please click here. Unfortunately, because of fungicide resistance development this type of program is no longer effective and is no longer recommended for CPM control.
Over the past 10 years, there have been a number of new fungicides released with new modes of action (i.e., new FRAC groups) for CPM control in cucurbit crops. Unfortunately, all have a moderate to high-risk for resistance development because of their specific modes of action. The good news are these new fungicide chemistries have less effects on humans, non-target organisms, and the environment.
These fungicides include:
- FRAC group 13 (quinoxyfen)
- FRAC group 39 (fenazaquin)
- FRAC group 50 (metrafenone)
- FRAC group U06 (cyflufenamid)
- FRAC group U013 (flutianil)
Not all of the fungicides listed above are labeled for all cucurbit crops. Growers will need to refer to local recommendations and the label for crop specifics. Remember, the label is the law.
These fungicides offer new strategies when it comes to controlling and mitigating losses to CPM. Instead of rotating two fungicides with a moderate to high-risk for resistance development every other week ( A – B – A – B), growers now have option to reduce the total number of times any single fungicide might be applied during the production season; further reducing the risk for resistance development to any one mode of action. For example, in pumpkin, a new CPM preventative fungicide program may look like this:
A – B – C – D – E – A – B – C – D – E
Where A=(FRAC group 3);B=(FRAC group 13); C=(FRAC group 50); D=(FRAC group U013); E=(FRAC group 11)
A protectant fungicide such as chlorothalonil or mancozeb should be added to the tank mix with each high-risk fungicide to reduce selection pressure and to help control other important diseases such as anthracnose and plectosporium blight.
In this type of CPM preventative program any one high-risk fungicide would only be applied twice per growing season and 5 weeks apart greatly reducing the risk for fungicide resistance development. Importantly, for cucurbit growers, the easiest method to mitigate the potential for fungicide resistance development are to reduce the total number of applications of any one high-risk fungicide during the production season.
When to start spraying for CPM
Initiating a preventative spray programs begins with paying attention to Extension reports, scouting, and when the crop was seeded. If the crop is seeded the early-spring (i.e., early to late May) there is a very good chance CPM is not present in the mid-Atlantic region. If CPM is not present, there is no need to initiate a spray program using high-risk fungicides. In this instance, general protectant fungicides such as chlorothalonil will help mitigate other foliar diseases. As cucurbit crops are seeded into early to mid-June (and afterward) the risk for CPM development will rise in the mid-Atlantic region. This is when scouting and paying close attention to Extension reports becomes important. The first application should be done when CPM has been detected in the immediate region or when it is detected by scouting (e.g., with one lesion found on the underside of 45 mature leaves per acre). This will help reduce the use of unwarranted high-risk fungicide applications early in the production season. Importantly, the use of PMR or PMT cucurbit varieties will also help delay the onset of CPM development as well. Once CPM preventative fungicide programs are initiated, applications need to occur at every 7 to 10 days (at the latest) for as long as you expect to harvest (e.g., summer squash) or hold the crop (e.g., pumpkin and winter squash). During harvest, growers need to pay careful attention to pre-harvest intervals because they may vary significantly between different FRAC groups or fungicides within the same FRAC group (a good example are fungicides in FRAC group 3). Once harvest is complete, those blocks or fields need to be destroyed immediately to help reduce the spread of CPM to other blocks or fields that are scheduled to be harvested later in the production season. This is especially important for other diseases such as cucurbit downy mildew.
In some instances, rotating between many different FRAC group fungicides are not an option because the chemistries aren’t available for use. An example would be leaf spot control in spinach, where FRAC groups (7, 11, 7 + 11, 7 + 12, and 9 + 12) are available. In this example, options for control might look like this:
A – B – C – D
Where A=(FRAC group 7); B=(FRAC group 9 + 12); C=(FRAC group 11); D=(FRAC group 7 + 12)
Here, we have maximized the use of as many different FRAC groups as possible and spread their use as far apart as we can during the production season. Its important to remember that fungicides with more than one active ingredient (e.g., 7 + 11) should also be rotated as far apart as possible with fungicides that contain the single active ingredient (e.g., FRAC group 7 or FRAC group 11).
Monitoring fungicide efficacy
With the use of high-risk fungicides, all growers need to monitor fungicide efficacy accordingly. Once the lack of efficacy is detected there is a chance that fungicide resistance might be present. Importantly, the lack of efficacy should not be misconstrued with poor applications or waiting too long between fungicide applications. Reports of poor efficacy from Extension personnel from one region may not reflect fungicide efficacy in another region. Therefore, fungicide efficacy needs to be done at the farm level and the only way to accomplish this is to scout your fields and know what is and isn’t working for you.
The principles mentioned above also extend to other important diseases in vegetable production where there are multiple FRAC groups with high-risk fungicides available to control specific diseases. As a general rule, growers need to rotate as many different modes-of-action (i.e., fungicides from different FRAC groups) as possible during the production season to help mitigate fungicide resistance development in conjunction with best management practices.
For more information on fungicide use, FRAC groups, and specific control recommendations please see the 2020/2021 Mid-Atlantic Commercial Vegetable Production Recommendation Guide.
