Lettuce

New UCCE Advisors Bring Fresh Ideas to Protect Lettuce From INSV, Pythium Wilt

By Mike Hsu, UCANR

Salinas Valley lettuce growers lost about $150 million in 2022 due to diseases

A stormy winter could portend another devastating year for the lettuce industry in the Salinas Valley, which saw approximately $150 million in lost gross revenue in 2022 due to INSV (impatiens necrotic spot virus) and associated diseases. Recent drenching rains might mean more weeds – overwintering “reservoirs” for the tiny insect, the Western flower thrips, that carries INSV.

Or the extreme precipitation could benefit growers, as thrips in the soil – during their intermediate stage of development – might be drowned in the waterlogged fields.

As with so many aspects of the INSV crisis, the ultimate effects of flooded fields on thrips populations remain unknown.

“We don’t know if thrips are just so persistent and so stable in that pupal stage that maybe they will emerge unaffected,” said Kirsten Pearsons, University of California Cooperative Extension integrated pest management farm advisor for Santa Cruz, Monterey and San Benito counties. “There’s just so much about their biology and ecology in the Salinas Valley that we just don’t know.”

The mystery of thrips, INSV and soilborne diseases (namely Pythium wilt) is why UC Agriculture and Natural Resources assigned Pearsons to the area last November and hired Yu-Chen Wang in October as UCCE plant pathology advisor for the three counties.

“They’re stepping in at a critical moment,” said Richard Smith, the region’s UCCE vegetable crop production and weed science advisor who retired in January after a 37-year career. “They’ve gotten grants funded already – and that’s just incredible. They’re hitting the ground running.”

Experienced in disease diagnosis and collaboration with growers and industry partners, Wang said her pathology background – paired with Pearsons’ entomology expertise – will be crucial in addressing INSV and other diseases.

“It is important for Kirsten and me to work together and provide different insights for the vector and the pathogen, respectively,” Wang said.

‘It’s going to take everything to get a crop’

One priority is untangling the dynamics of INSV and Pythium wilt co-occurrence – the subject of ongoing research by JP Dundore-Arias, a plant pathologist at California State University, Monterey Bay. While the vegetables may tolerate one disease or the other, their one-two punch often deals the lethal blow. 

“The challenge is – which is why it’s great to have Yu-Chen and Kirsten – is that we have so many problems now, whether it’s Fusarium (wilt), or Verticillium (wilt), or Pythium, or INSV,” said Mark Mason, pest control adviser for Nature’s Reward, which primarily grows lettuces on 5,000 acres across the Salinas Valley.

Mason said that co-infections on his crops (sometimes with three or four diagnosed diseases) make it difficult to assign monetary damages to a specific pathogen, but he noted he has seen fields with “100% loss.” According to the Grower-Shipper Association of Central California, about 11,500 acres were deemed not harvestable in 2022, representing 12% of lettuce industry acreage.

Given the gravity and complexity of the disease dilemma, Pearsons said she has been fielding calls from growers seeking new and better solutions – ways to improve existing tools, techniques borrowed from other crop systems, and additional biological or chemical means of control.

And although there are a couple of pesticides that manage the disease-carrying thrips reasonably well, growers and researchers are worried about their diminishing efficacy due to overuse. Plus, they only constitute a short-term fix.

“Managing the thrips will only reduce the amount of INSV that can get transmitted,” Pearsons explained. “You can kill 99.9% of the thrips, but you get one thrips that has INSV that enters a field, and now you have an infected lettuce plant. All of the thrips are going to come and they can spread it from there; pesticide slows things down, but it’s not going to eliminate it.”

Finding disease-tolerant lettuce cultivars is a more sustainable approach. Trials conducted last year by Smith, Wang and others identified several varieties that appeared to hold up well to Pythium and INSV. While additional research could maximize their potential benefit, Wang said even the hardier cultivars will lose their resistance over time, and a multi-layered INSV strategy with “integrated management tools” is crucial.

“We realized, when this thing started happening, that we cannot spray our way out of this problem,” Mason said. “We need varieties; we need management practices; we need pesticides…it just seems like it’s going to take everything to get a crop.”

Weeds key to disease control

An all-hands-on-deck approach helped control thrips-harboring weeds last winter. With fields drying out from January storms, Smith said communities must get back to weed management – with a focus on prominent weed hosts for INSV and neglected areas adjacent to farms. Hotspots of infection last year were traced to industrial lots that were overlooked during the weeding process.

“People can’t lose sight of the fact that we still need to be controlling the weeds in key areas, because that’s the reservoir of the virus during the winter,” Smith said. “We have to stay on task with that.”

Yet despite the diligent weed abatement, crop damage from INSV and Pythium was widespread in 2022, and Smith said it’s “very possible” that high heat during the summer was a contributing factor to especially prevalent disease in fall. Thrips populations tend to thrive in warmer weather, Smith said, but much more research needs to be done to understand the basic biology of the insect, including how they acquire the virus and how they spread it.

High hopes for future

Pearsons cited the work of Daniel Hasegawa, a research entomologist with the U.S. Department of Agriculture, who leads teams in monitoring thrips populations in several locations across the Salinas Valley. Currently the counting of thrips on sticky card traps is done manually, but Pearsons and Mason mentioned the possibility of using AI and machine learning to expedite that process.

Mason said that the grower community is excited about the new technologies and ideas that Pearsons and Wang are bringing to the region. As a participant in the search for candidates to fill the advisor positions, Mason said “they were, in my opinion, by far the best fit for what we were looking for.”

“I hope they stay here for 30 years,” he added.

The new advisors both noted the palpable energy and cooperative spirit in the Salinas Valley to proactively meet the challenge.

“Looking to the past, there have been other outbreaks and diseases that they’ve managed to overcome,” Pearsons said. “These farmers are resilient and creative and I fully believe that lettuce will still be growing here for years to come – it might look a little different, and it might take a little bit of a painful period to get to that point, but I think that we’re going to be able to come up with some solutions.”

And while there are concerns that some lettuce growers might decide to leave the region, Wang said she also believes in the industry’s strong roots and rich history.

“Salinas Valley has had a beautiful climate for lettuce for so many years; there are some undeniable advantages here,” she said. “This is still the best place in the United States – and maybe the world – to grow lettuce.”

2023-02-03T16:01:34-08:00February 3rd, 2023|

Decertification Action

If an LGMA member is found to be out of compliance with the food safety standards the program can decertify the company. 

LGMA members work to provide the safest leafy greens on the market through a rigorous set of food safety practices that are verified by audits conducted by the California Department of Food and Agriculture. However, if a company is found to be out of compliance with the food safety standards the program can decertify a member. Although this happens rarely, California LGMA and the California Department of Food and Agriculture recently decertified a member company.

The LGMA audit verifies compliance with over 500 food safety checkpoints. LGMA members are required to be 100% in compliance, which means that if an audit identifies a non-conformity the member must submit corrective actions to the LGMA Compliance Officer. If a company fails to demonstrate full compliance, they are subject to decertification.

Decertification means that a company cannot present itself as a certified LGMA member, nor use the LGMA Service Mark. Government agencies and produce buyers rely on LGMA certification for supplier verification. Loss of certification potentially means a loss of sales, including product being turned away from international borders. An up-to-date list of LGMA members and their certification status is available on our website: https://lgma.ca.gov/certified-members

2022-10-19T09:02:16-07:00October 19th, 2022|

Consumer Protection Is Top Priority for LGMA

New LGMA Irrigation Requirements Mean Heightened Food Safety Measures

By Mikenzi Meyers, Associate Editor

As consumer protection continues to be a number one priority for producers, main pathogen routes are of the utmost importance for guaranteeing safety. The California Leafy Green Marketing Agency (LGMA) is a program that works to continually keep the lettuce industry safe and maintain confidence in food safety programs—but as pathogens begin to evolve, it takes a team effort to combat future threats.

Mike Villaneva, LGMA technical director, told California Ag Today, “It’s been a tough 18 months, and it’s the challenge with these outbreaks … we never really have a good answer about what happened and how it happened.”

In the leafy greens industry, water becomes a focal point in pathogen prevention. “We’ve got 12 years of testing water, and we’re pretty confident of water in the deep wells along the Central Coast, but down south is a different ballgame—that’s open surface water,” Villaneva said.

On April 19th, the LGMA board met and voted to strengthen mandatory food safety practices required on farms. One facet included prohibiting overhead irrigation 21 days prior to harvest unless the water is sanitized.

“They’re looking at some other potential testing and data that could lower that down to 14, but right now they’re sticking with the 21 overhead,” Villaneva said.

The California Leafy Green Marketing Agency continues to show their commitment to ensuring a safe, stable food supply through foodborne illness prevention. More information about the program can be found on their website at www.lgma.ca.gov.

2021-05-12T11:01:48-07:00May 23rd, 2019|

Leafy Green Marketing Agreement Issues New Food Safety Guideline

New, More Stringent Food Safety Practices Adopted to Prevent Outbreaks

By April Ward, LGMA Communications Director

The California Leafy Greens Marketing Agreement Board met April 19 and voted to strengthen mandatory food safety practices required on farms.

This means that every box of leafy greens placed into commerce by a certified LGMA member will soon be produced under new, more stringent requirements that are designed to reduce risk when it comes to water used in growing leafy greens. The updates include specific directives such as no longer allowing the use of untreated surface water for overhead irrigation of leafy greens prior to harvest.

The LGMA program has always required growers to test their water because it can be a carrier of pathogens. But the new requirements now include additional safeguards that ensure farmers categorize the source of the water; consider how and when water is applied to the crop; conduct testing to assure the water is safe for the intended use; sanitize water if necessary; and verify that all of the above precautions have been taken

The new standards approved by the LGMA Board are in direct response to investigations conducted by the U.S. Food and Drug Administration into last year’s e. Coli outbreak involving romaine lettuce. Clues pointed to irrigation water from sources such as canals and reservoirs as a possible cause of the both the November outbreak and the one associated with romaine from Yuma last spring.

Government and the produce industry, in general, looked to the LGMA as the way to improve the safety of leafy greens. The leafy greens industry group, facilitated by Western Growers, has been working with industry members, growers and members of the academic community to fashion new and more stringent requirements for agricultural water use. And, in fact, the actions taken by the LGMA Board have effectively changed the way 99 percent of the leafy greens in California are farmed.

The LGMA will begin immediately to make sure everyone in the leafy greens community understands how to comply with the new requirements. The updated LGMA Food Safety Practices document is available on our website here. Additional information on specific changes to the LGMA food safety practices will be provided in the coming weeks and dates for workshops and webinars for both leafy greens industry members and the buying trade will be scheduled soon.

The LGMA and its members have an obligation to produce safe leafy greens. We are very aware of the tragic impacts a foodborne illness can have on consumers, our customers, and our entire industry. We are all passionately committed to producing the safest leafy greens possible. The LGMA will continue to make changes to as needed to strengthen the food safety requirements for leafy greens.

For more on the new regulations, check out this YouTube video.

2021-05-12T11:01:48-07:00April 25th, 2019|

Lettuce Aphids Showing Up on Late Produce

Lettuce Aphid Pressure Has Been Steady

By John Palumbo, University of Arizona Professor/Extension Specialist, Department of Entomology

This season has been a banner year for aphids in the desert.  Aphid pressure has been steady on most crops throughout the spring.  Consistent with the warm weather we have been experiencing lately, Lettuce aphids, Nasonovia ribisnigri, (aka., Red aphid) have shown up in desert lettuce again.

The last time lettuce aphid was this abundant on desert produce was the spring of 2012.  However, in the past couple of weeks, I’ve identified lettuce aphid appearing on both head lettuce and romaine in Roll and Wellton. I’ve also had reports of the aphid showing up in the Imperial Valley.

At the Yuma Ag Center, we began seeing lettuce aphid a couple of weeks ago on untreated lettuce, and they have recently built up to high numbers. Previous experience has taught us that daytime high temperatures in the 80’s are ideal for population growth.  A few things to remember about lettuce aphids relative to the other aphids we commonly see.

First, the immature nymphs are small and have a red appearance, whereas the apterous adults are typically a large brown colored aphid with dark bands running across the abdomen.  Second, among the crops we grow locally, lettuce aphids are only found on the lettuce types(Lactuca spp.)

Lettuce aphids prefer to colonize the terminal growth, and can often be found in heads or hearts, whereas green peach aphids are often found on the frame leaves in high numbers before moving into the heads. Sampling should be focused on the terminal growth of young plants and in the heads and hearts of older plants. Third, they can reproduce prolifically, producing many more winged alates than other species, which can quickly lead to widespread abundance throughout a field or a growing area.  Finally, as the saying goes “he who hesitates is lost”.

If lettuce aphids are found on your lettuce, it is recommended that you respond quickly with an insecticide treatment. The product of choice is Movento at 5 oz/ac. Because of its systemic activity, Movento will reach aphids in the protected terminal growth.

Be sure to include a penetrating adjuvant for best results at a rate of at least 0.25% v/v. It normally requires 7-10 days of activity before a significant reduction in the infestation is observed. For more information on lettuce aphid please refer to Lettuce Aphid on Late Season Produce.   If you’re finding lettuce aphid on organic lettuce, you’re out of luck; none of the registered biopesticides will control this aphid.

2021-05-12T11:01:49-07:00April 9th, 2019|

California Crop Values for 2017 Released by CDFA

Full Statistics Now Available For the Crop Year 2017

News Release

The California Agricultural Statistics Review for crop year 2017 has been released. It reports that California’s farms and ranches received more than $50 billion in cash receipts for their output. This represents an increase of almost 6 percent in crop values compared to 2016.

California’s agricultural abundance includes more than 400 commodities. Over a third of the country’s vegetables and two-thirds of the country’s fruits and nuts are grown in California. California is the leading U.S. state for cash farm receipts, accounting for over 13 percent of the nation’s total agricultural value. The top producing commodities for 2017 include:

Dairy Products, Milk — $6.56 billion

Grapes— $5.79 billion

Almonds— $5.60 billion

Strawberries— $3.10 billion

Cattle and Calves — $2.53 billion

Lettuce— $2.41 billion

Walnuts— $1.59 billion

Tomatoes— $1.05 billion

Pistachios— $1.01 billion

Broilers— $939 million

Complete Report at this Link:

https://www.cdfa.ca.gov/Statistics/PDFs/2017-18AgReport.pdf

2019-01-10T15:52:42-08:00January 10th, 2019|

Mechanically Harvesting Broccoli

Saving Labor Cost in Broccoli Harvest

By Jessica Theisman, Associate Editor

Josh Ruiz and Monsanto Seeds have partnered up to harvest broccoli mechanically. Ruiz is vice president of AG operations with Church Brothers Farms in Salinas.

“They brought us a genetic variety of broccoli where the head does sit up higher. When it comes to broccoli, all varieties have their heads mature at different rates,” Ruiz explained.

That being said, the fields must be harvested multiple times as the crop matures. With these new genetics, you can get it all done in one sweep.

“I want it to be as simple for my people because I want them to be happy. Cutting once and moving on is what makes them happy,” Ruiz said.

There are a bunch of growers around California, Arizona and in Mexico; they want to get that ground back and use it one more time before the season’s over.

“This gives them about a month’s worth of time back in their hands, which, in the world we live in, is huge,” Ruiz said.

Ruiz said he is going to continue to develop mechanical harvesting for other crops.

“Iceberg and Romaine are the next two big projects,” he explained.

Iceberg is known to be the “holy grail.” Ruiz has a prototype in the works, and he’s willing to work with anyone who is willing to partner.

“The Broccoli Project, the last five years, has overwhelmed my team and me, but we are ready for the next challenge,” he said

“My day to day is focused on not only running the AG operations for Church Brothers, but I spend a lot of my day focused on innovation and how can we do things better, quicker, faster, cheaper,” he continued.

Ruiz is passionate about automation and innovation. He is currently working with lettuce, romaine, broccoli, cauliflower, spring mix, spinach, and kale.

He said his interest in mechanical harvesting is mostly based out of labor issues, but it goes further from there.

“I see this as the future. I’m not the computer guy, and I’m not the engineer, but I love that stuff, and I want to go find out how to make it possible for me to learn,” he said.

Approximately five years ago, Ruiz began his relations with Monsanto with the Broccoli Project.

“We just unveiled our brand new version of our machine, and I have no doubt in my mind that it’s going to be out there in the field. You’ll see it going down the Salinas Valley from here on out.”

2021-05-12T11:05:07-07:00January 3rd, 2019|

FDA Releases Possible Factors for 2018 E. Coli Outbreaks

Leafy Greens Industry and Public Were Severely Impacted

By Hank Giclas, Western Growers Sr. Vice President, Strategic Planning, Science & Technology

Recently, the U.S. Food & Drug Administration released an environmental assessment that provides an overview of factors that potentially contributed to the contamination of romaine lettuce with E. coli that was implicated in a 2018 multi-state foodborne illness outbreak. The assessment can be found here and includes the background on the outbreak; the environmental team approach; and factors potentially contributing to the introduction and spread of E. coli; along with recommendations for the prevention E. coli in leafy greens.

FDA recommends that growers and processors of leafy greens:

  • assure that all agricultural water (water that directly contacts the harvestable portion of the crop) used by growers is safe and adequate for its intended use (including agricultural water used for application of crop protection chemicals);
  • assess and mitigate risks related to land uses near or adjacent to growing fields that may contaminate agricultural water or leafy greens crops directly (e.g. nearby cattle operations or dairy farms, manure or composting facility);
  • verify that food safety procedures, policies, and practices, including supplier controls for fresh-cut processors, are developed and consistently implemented on farms (both domestic and foreign) and in fresh-cut produce manufacturing/processing food facilities to minimize the potential for contamination and/or spread of human pathogens;
  • when a foodborne pathogen is identified in the growing or processing environment, in agricultural inputs (e.g., agricultural water), in raw agricultural commodities or in fresh-cut, ready-to-eat produce, a root cause analysis should be performed to determine the likely source of the contamination, if prevention measures have failed, and whether additional measures are needed to prevent a reoccurrence; and
  • Local in-depth knowledge and actions are critical in helping resolve potential routes of contamination of leafy greens in the Yuma growing region, including Imperial County and Yuma County, moving forward. FDA urges other government and non-government entities, produce growers and trade associations in Yuma and Imperial Counties to further explore possible source(s) and route(s) of contamination associated with the outbreak pathogen and with other foodborne pathogens of public health significance. This information is critical to developing and implementing short- and long-term remediation measures to reduce the potential for another outbreak associated with leafy greens or other fresh produce commodities.

The findings in the Environmental Assessment appear to provide little new information but will be closely reviewed by Western Growers and others as part of our industry’s ongoing efforts to ensure food safety.

Immediately after the outbreak, Western Growers collaborated with the leafy greens industry to help lead a task force that would assess the source of the outbreak, as well as develop recommendations to prevent future outbreaks. While sources of contamination remain uncertain, the task force made concrete recommendations to industry for assuring water is safe and adequate, assessing and mitigating risk from adjacent land uses as well as others to address risks from equipment and climatic conditions.  These recommendations go well beyond the requirements of the FDA’s own Produce Safety Rule and have already been incorporated into the California and Arizona LGMA requirements. State auditors are now charged with verifying adherence to these new controls through announced and un-announced audits that occur throughout the seasons. The industry is furthering its efforts to learn more including through research guided by respected entities such as the Center for Produce Safety and working directly with California and Arizona academic teams. There is a strong and broad commitment to continually work to improve our food safety system.

Other related information posted by FDA includes:

2021-05-12T11:05:08-07:00November 9th, 2018|

Spotted Wilt Virus Impacting Tomatoes Again

Virus has Gotten Past Resistant Gene

By Patrick Cavanaugh, Editor

Tomato spotted wilt virus is becoming big in the central San Joaquin Valley, according to Tom Turini, University of California Cooperative Extension Farm Advisor in Fresno County for vegetable crops. The virus had earlier been spotted in lettuce, and this has caused some concern in this season’s tomato crop.

Tom Turini

“We had some concerns early in the season that we might be looking at a year where it’ll become a challenge, because we were finding it in lettuce back in February and March in the Huron area,” Turini said. “And then we notice that tomatoes were showing the virus symptoms. We had been managing tomato spotted wilt in processing and fresh market tomatoes largely with a resistance gene, and it seemed that the resistance was breaking.”

The virus is spread by thrips, and the gene in the tomato was the biggest deterrent in combating thrips.

“We were also talking about an IPM program, but the industry was leaning on this gene. This gene became a big part of their spotted wilt prevention program,” Turini said. “While sanitation of weeds was practiced, and there was some thrips management, it was really dependent upon this single gene resistance in the tomatoes, and as of 2016, we saw evidence that that gene was no longer performing.”

Because the virus can wipe out entire tomato fields, researchers are scrambling to find a new way to deter the thrip spreading the virus on tomatoes.

2021-05-12T11:01:55-07:00June 18th, 2018|

Labor Contractor Fresh Harvest Deep in Vegetable Harvests

Fresh Harvest Relies on H-2A

By Jessica Theisman, Associate Editor

Steve Scaroni, along with his wife Brenda, owns Fresh Harvest, a premier labor provider, staffing and harvesting company for the agricultural industry in the western United States.

Steve Scaroni, with Fresh Harvest.

“Expansion for Fresh Harvest is coming, but the main emphasis is crops related to salads. They even expanded into citrus last year,” Scaroni said.

Fresh Harvest has also expanded into pears. Vegetables are the heart and soul of Fresh Harvest.

“Anything that goes into a salad, a lot of lettuce, romaine, broccoli; we touch a lot of salads every day,” he said.

The H-2A temporary agricultural program allows agricultural employers who expect a shortage in domestic workers to bring non-migrant foreign workers to the U.S. to perform agricultural services for a temporary or seasonal nature.

“If it wasn’t for H-2A, I wouldn’t be in business,” Scaroni said.

Scaroni explained that the H-2A gets legal workers to serve his customers demands for the services he offers. A majority of the demands are labor and harvesting, along with other farm services.

“We’re bringing up 100 irrigators this year to put throughout the Salinas Valley because our Salinas customers can’t get enough irrigators,” he said.

Laborers that show great work ethic will be able to work for a longer period of time. A worker could technically stay if moved from contract to contract.

“If the timing works, he gets up to three years, but then he has to go back for 90 days,” Scaroni said.

2018-06-07T15:50:41-07:00June 7th, 2018|
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