Pests and Diseases

Reducing ACP Spread In California

Beth Grafton-Cardwell: Spread of Disease Must Be Prevented

By Patrick Cavanaugh, Editor

Collaborative changes are being made to combat the Asian Citrus Psyllid (ACP). Beth Grafton-Cardwell is the director of Lindcove Research and Extension Center near Exeter, as well as a research entomologist with UC Riverside. She recently spoke at the 2019 Citrus Showcase in Visalia as a key speaker on the state of Huanglongbing (HLB) in California, with an overview of how to prevent ACP,—which vectors HLB, a fatal disease to citrus—from moving around the state.

“We were trying to communicate why we’ve made the changes we’ve made for the industry that has been a collaborative effort between CDFA, growers, and the university,” Grafton-Cardwell said. “We need better ways to prevent psyllids from moving around the state because they might have HLB in their bodies, and we’ve got to prevent the spread of the disease.”

Beth Grafton-Cardwell

The Florida citrus industry did not do a great job in containing the Psyllid, and now HLB is rampant in the state’s citrus industry, which has devastated the citrus economy there.

“Florida found that they did not do much to control psyllid movement, and they found that psyllids were moving in bulk citrus bins and retail nursery plants around the state, and within a concise amount of time, they spread the Psyllid and the disease everywhere,” Grafton-Cardwell said. “We’re trying to avoid that. We have 100% tarping of citrus truckloads. We have treatments that have to be done if growers want to move citrus between major zones in California, so that we can prevent that kind of movement.”

Conversations continue about quarantine areas in California to reduce spread.

“There’s been a lot of discussion regarding quarantines because it’s painful for some growers who have low Psyllid numbers to have to treat and to move their fruit to other zones.”

“There’s been a lot of questions. We did a lot of scientific analysis to look at impacts as well as numbers. It’s not just about psyllid numbers; it’s about their impact if growers were to move the disease into a high citrus growing region,” Grafton-Cardwell explained.

California Ag Today2021-05-12T11:01:48-07:00May 8th, 2019|

Food Safety Is Paramount In California Agriculture

Researchers Hone in on Bacteria Genome to Isolate Pathogens

By Laurie Greene, Founding Editor

Food safety is paramount in the specialty crop farm industry; but when a bacterium causes a food safety problem, there is important work to determine the exact fingerprint of that bacteria.

Matthew Stasiewicz, assistant professor of applied food microbiology in the area of food safety at the University of Illinois at Urbana-Champaign, Department of Food Science & Human Nutrition, said it’s important to determine the genome of these bacteria that are causing problems.

“The biggest thing that has happened in the field of food safety is that the U.S. government has committed to using whole genome sequencing as a primary public health surveillance tool. So, if you have a foodborne disease and go to a doctor, and they isolate that organism, it will go into a nationwide database—now international database—that can link that organism’s genome sequence to whatever else shows up in the database. So, at the same time, if pathogens are isolated from foods potentially as part of an outbreak, those sequences can be [entered into the database] and [experts can] gather information from food sources as well as clinical patients. And that’s just a major tool.”

Stasiewicz said the genome is important because we need to know the true source of that bacteria. “The pathogens that can make you sick can be distributed in the environment.

“So just because you potentially got sick from eating food and maybe you got an E.coli O157:H7 infection in your hometown, even if someone else two towns away got the same infection with E.coli O157:H7, we don’t know if that’s related, even if you potentially ate the same food,” Stasiewicz said. “That could come from the soil in your town, your local grower, a local grower somewhere else, or from a common source, common grower, or common packer, and gotten you both sick. This genome sequence information allows us to make those links much more clearly.”

Stasiewicz said this is an important pioneering effort to reduce food safety illnesses. “Importantly, from the food standpoint,” Stasiewicz said, “we want that information so we can find that and eliminate it. No food processor wants to make anyone sick. No grower wants to make anyone sick. So, we need to identify those concerns.”

California Ag Today2021-05-12T11:05:04-07:00May 6th, 2019|

Tulare Center Trains UC Davis School of Veterinary Medicine Students

UC Vet Students Learn About Livestock Animals in Tulare

By Patrick Cavanaugh, Editor

VMRTC is the Veterinarian Medicine Training and Research Center located in Tulare. The facility is an extension of the UC Davis School of Veterinary Medicine. The site offers education and training to veterinarians by offering senior veterinary students and residents on-the-farm clinical medical training and residencies in dairy production medicine.

Nathan Brown, a UC Davis veterinary student, is working on practicals in and out of a hospital setting.

“We do rotations in the hospital and outside of the hospital. We have a teaching center and, in addition, we have our California Animal Health and Safety Laboratory System (CAHFS), which is involved with diagnosing foreign animal diseases,” Brown said. “That is sort of the main mission.”

“In the mornings, we do herd checks, we go out to different dairies. We palpate cows for diagnosis of pregnancy, and we’re under the supervision of some of the veterinarians that work at our center,” Brown explained. “In the afternoons, we work on a variety of different projects. One of the projects that we’re working on currently is milking frequency. We are looking at different variables that go into whether or not it’s profitable to move from either two to three times a day or three times a day to two times a day.”

Brown said that the students at the Tulare center are doing their livestock track through UC Davis. “We’re all in our fourth year. It’s been a wonderful experience. Tulare is a great place, and it’s good to see a different part of California.”

Students studying at the center decide which direction they will take regarding animal type or other medical pursuits.

“After our second year, we make a decision about whether we do small animals or large animals,” Brown said. “Some people do equines, other focus on zoo animals—there is a variety of options in our profession and that our school offers.

Brown is pursuing livestock medicine, but he has a commitment to the Air Force to do public health epidemiology for them.

Army veterinarians do clinical medicine for animals on the base. They focus on German shepherd dogs and horses, and they also do some food safety.

“As as a veterinarian in the Air Force, it’s essentially veterinary public health, and my role will be epidemiology on a base, so that’s actually more human focus, and food safety,” Brown said.

“If you kind of think about the historical roots of veterinary medicine, much of the role of veterinarians has been ensuring that food is safe for humans to consume, meaning that the animals are healthy before they get ready for human consumption,” Brown explained. “We must ensure that there’s no points of contamination so that all the food that people eat in this country is healthy and nutritious, and we don’t have to worry about disease.”

Most bases have a veterinary clinic, primarily staffed with army veterinarians.

“My hope is to do some amount of clinical practice at these clinics to sort of keep my veterinary skills relevant. And I’ve had some good advice from some epidemiologists who works at the CDC,” Brown said. “He told me that at least for him, it’s made him a better epidemiologist by keeping his clinical skills relevant because thinking about that differential diagnosis is really a big part of trying to find the cause of a disease.”

California Ag Today2021-05-12T11:17:08-07:00May 2nd, 2019|

Weedy Rice—Not as Simple as it Sounds

Weedy Rice is A Pesky Rice Type in Production Rice Fields

By Mikenzi Meyers, Associate Editor

Contrary to its name, weedy rice is not in fact weeds in rice—but it is presenting several challenges to California rice growers. To help farmers combat the pesky variety, UC Davis Ph.D. student Liberty Galvin and the horticulture and agronomy graduate group have conducted extensive research.

According to Galvin, the genetic and physiological properties of weedy rice are the same as the cultivated varieties consumers typically eat. So what’s the issue? Galvin said that besides the fact that weedy rice is off in its coloring, it’s nearly impossible to harvest.

“The issue is that the seed shatters, or basically falls to the ground. So when you go through and try to harvest it, the grain does not get collected in the harvester,” Galvin explained.

Although right now it seems that commercially growing weedy rice is not an option, there are ways to prevent it. Galvin’s research found that drilling the seeds at least two inches into the soil will eliminate seed germination or emergence in the field. This is especially useful in California, where tillage is done only to prepare the field, not plant the rice itself.

Galvin said that while growers can produce their own rice seed, it has to be certified by the California Crop Improvement Association or a Rice Seed Quality Assurance Program. In all cases, growers are required to plant only certified rice seed so there is no opportunity for traces of weedy rice to enter the soil.

“That is why tillage depth is so important, because that’s how you reduce your seed bank,” she said.

California Ag Today2021-05-12T11:05:04-07:00April 30th, 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.

California Ag Today2021-05-12T11:01:48-07:00April 25th, 2019|

Fighting for Citrus Industry

Continuing to Fight For Citrus Industry’s Longevity Requires Teamwork

By Jim Gorden, Committee Chair, Citrus Pest and Disease Prevention

For more than two centuries, citrus has grown strong in California’s yards and groves—serving as a source of nourishment, income, and tradition for many different individuals—but the citrus industry is at risk due to Huanglongbing’s (HLB) growing presence in California.

Jim Gorden

In 2018, HLB was found in more than 600 residential citrus trees in Southern California, and despite the program’s thorough surveying efforts, HLB has not been found in a commercial grove, but we must continue to hold strong. It has never been more important for all of us— including the Citrus Pest & Disease Prevention Program (CPDPP), regulatory authorities, the citrus industry, the scientific community, and others—to work together to prevent the spread of the disease and save California’s citrus industry.

While much has changed since the citrus industry came together ten years ago to support the creation of the CPDPP, one constant remains: the program’s dedication to fighting HLB. This year, the Citrus Pest & Disease Prevention Committee (CPDPC) created a strategic plan for combatting HLB now and in the future. The plan identified five prioritized strategies to achieve CPDPP’s goals of keeping HLB out of commercial groves, limiting Asian citrus psyllid (ACP) movement in the state and fine-tuning the program. In addition, the program agreed to align its annual budget in support of the strategies, which can be viewed in this report.

With this plan comes additional responsibilities for all individuals involved. The CPDPC understands HLB isn’t the only issue posing a threat to your business and our industry – but it’s one we can’t ignore. This report highlights the many activities the program and our partners are doing across the state to protect commercial groves from HLB, but we are only as strong as our weakest link.

Looking forward, much is at stake for California citrus growers, packers and workers as the industry faces its biggest threat yet in HLB. I encourage you to connect with the program, your local pest control district, or task force, and follow best practices for managing the ACP and HLB. If we sit idle, hoping others will take action for our benefit, we are welcoming this devastating disease into our groves.

But, by working together, we can protect California’s commercial citrus industry from devastation—sustaining our livelihood and the legacy of California citrus.

For more information on the Citrus Pest & Disease Prevention Program Click here.

California Ag Today2021-05-12T11:01:49-07:00April 25th, 2019|

Protecting Melons From Silver Leaf Whitefly

Avoid Planting Near Earlier Planted Crops

By Patrick Cavanaugh, Editor

Silver leaf whitefly can be a severe yield-robbing pest in melons, but there are ways to prevent the damage, according to Tom Turini, a UCANR Vegetable Crops Adviser in Fresno County.

“A tactic is going to depend upon planting. If you’re able to put the crop into an area where you’re not next to earlier planted melons or cotton or known sources of whitefly, your likelihood of experiencing damaging whitefly levels is going to be lower,” Turini said. “Growers can’t always do that, but that’s part of the approach when you can. You’ll limit your risk.”

Tom Turini, UCANR Farm Advisor, Fresno County

Turini said the pest could mainly be a problem when you’re putting in those late melon fields when whitefly populations are higher.

“Whiteflies are not good fliers, so when you put those fields in areas where you don’t have sources of whitefly nearby then you will have less pressure for sure,” Turini said.

“Then there are some insecticide programs that you can look at, particularly when you know you’re going to have pressure,” Turini explained. “If you’re coming into high temperatures, and you’ve got late-planted melons, you may want to start with soil-applied insecticides, through the drip. It could be Admire; also Sivanto is a newer material that that has registration and has shown efficacy in desert production areas, which have much higher pressures and more consistent pressures than we do in the San Joaquin Valley.”

California Ag Today2021-05-12T11:01:49-07:00April 23rd, 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.

California Ag Today2021-05-12T11:01:49-07:00April 9th, 2019|

Quarantines in Place to Prevent ACP Spread

Quarantines Painful For Some Growers

By Mikenzi Meyers, Associate Editor

It’s been a tough road for citrus growers since the discovery of the Asian Citrus Psyllid (ACP) back in 2012. Those affected have been forced to quarantine their crops, a task that Beth Grafton-Cardwell, director of Lindcove Research Extension Center in Tulare and research entomologist with UC Riverdale, said can be difficult.

“There’s been a lot of discussion about the quarantines because they’ve been painful for some growers who have low psyllid numbers to have to treat them and move their fruit to other zones,” Cardwell explained.

Beth Grafton-Cardwell

The growing concerns have led to continuous research regarding whether or not the zones should be changed.

There have been more than 1,100 citrus trees that have tested positive for HLB. There have been more than 230 positive finds of the psyllid, and although this sounds like a big number, Cardwell said its actually normal due to how difficult the disease is to detect.

“We can’t tell that the tree is infected early on because a localized infection might be on one stem of the entire tree, and it might take a year before it moves throughout the tree,” she said.

Right now, quadrant sampling is being done, where four quadrants of the tree are sampled for the disease. Current samples are showing that one in four quadrants are coming back positive.

“It’s finding the trees that are infected that’s really difficult, and meanwhile, the psyllid is spreading, spreading, spreading the disease,” Cardwell said.

More information can be found at this link:

https://maps.cdfa.ca.gov/WeeklyACPMaps/HLBWeb/HLB_Treatments.pdf

California Ag Today2021-05-12T11:01:49-07:00April 5th, 2019|

Study: Remote Sensing of Weeds on Vineyards Has Merit

Aerial Sensing Of Weeds Saves Time and Labor

By Jessica Theisman, Associate Editor

There is a potential use of remote sensing with drones and vineyard weed management. Working on that research is Cody Drake, a senior at California State University, Fresno. He’s working with Luca Brillante, an assistant professor in the Department of Viticulture and Enology. Anil Shrestha is chair and professor, also in the Department of Viticulture and Enology at Fresno State. Drake’s research is at a vineyard in Napa County.

“The goal of my research is to make weed management practices in vineyards a little more efficient,” Drake said.

Currently, there is a lot of manpower, money, and time going into scouting for weeds and spraying.

“What we did with the drone is we wanted to map high-pressure weed zones to target spray in the field instead of spraying the entire field,” Drake explained.

This aerial scouting is hoping to become more efficient for time and labor.

“It’s all based on imagery. The drone gives us waypoints as to the areas where we need to spray. We have a company that’s called Drone Deploy, and they go through, and they stitch all the photos together,” Drake said.

Drake’s research has only been on vineyards so far, and his research has been proven to work.

“We did a 30-meter flight and a 10-meter flight, and that just shows the difference in how close you can get to identifying weeds species on the ground at a 30 meter height,” he said.

At 30 meters, it was very hard to tell which species was which. At 10 meters, the weeds were more identifiable.

“We would prefer to do another trial with a higher resolution camera. That way we can see the species, identify them a little easier and a little more efficiently,” Drake said.

By doing this, Drake and his team can pinpoint where the heavyweights are and just go spray that one area. For future research, they are going to try a camera with higher resolution to see if it can see through a denser vineyard.

California Ag Today2021-05-12T11:05:04-07:00April 1st, 2019|

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