Big Research Funds Continue to Fight Huanglongbing Disease

 $7 Million Multi-State Research Project Targets Citrus Threat HLB

UC ANR part of team led by Texas A&M AgriLife combating Huanglongbing disease

By Mike  Hsu UCANR Senior Public Information Representative

Citrus greening, or huanglongbing disease (HLB), is the most devastating disease for orange and grapefruit trees in the U.S. Prevention and treatment methods have proven elusive, and a definitive cure does not exist.

Since HLB was detected in Florida in 2005, Florida’s citrus production has fallen by 80%. Although there have been no HLB positive trees detected in commercial groves in California, more than 2,700 HLB positive trees have been detected on residential properties in the greater Los Angeles region.

“It is likely only a matter of time when the disease will spread to commercial fields, so our strategy in California is to try to eradicate the insect vector of the disease, Asian citrus psyllid,” said Greg Douhan, University of California Cooperative Extension citrus advisor for Tulare, Fresno and Madera counties.

Now, a public-private collaborative effort across Texas, California, Florida and Indiana will draw on prior successes in research and innovation to advance new, environmentally friendly and commercially viable control strategies for huanglongbing.

Led by scientists from Texas A&M AgriLife Research, the team includes three UC Agriculture and Natural Resources experts: Douhan; Sonia Rios, UCCE subtropical horticulture advisor for Riverside and San Diego counties; and Ben Faber, UCCE advisor for Ventura, Santa Barbara and San Luis Obispo counties.

$7 million USDA project

The $7 million, four-year AgriLife Research project is part of an $11 million suite of grants from the U.S. Department of Agriculture National Institute of Food and Agriculture, NIFA, to combat HLB. The coordinated agricultural project is also a NIFA Center of Excellence.

“Through multistate, interdisciplinary collaborations among universities, regulatory affairs consultants, state and federal agencies, and the citrus industry, we will pursue advanced testing and commercialization of promising therapies and extend outcomes to stakeholders,” said lead investigator Kranthi Mandadi, an AgriLife Research scientist at Weslaco and associate professor in the Department of Plant Pathology and Microbiology at the Texas A&M College of Agriculture and Life Sciences.

The UC ANR members of this collaboration will be responsible for sharing findings from the research with local citrus growers across Southern California, the desert region, the coastal region and the San Joaquin Valley.

“In addition to the ground-breaking research that will be taking place, this project will also help us continue to generate awareness and outreach and share the advancements taking place in the research that is currently being done to help protect California’s citrus industry,” said Rios, the project’s lead principal investigator in California.

Citrus trees in Florida suffer from HLB infection

Other institutions on the team include Texas A&M University-Kingsville Citrus Center, University of Florida, Southern Gardens Citrus, Purdue University and USDA Agricultural Research Service.

“This collaboration is an inspiring example of how research, industry, extension and outreach can create solutions that benefit everyone,” said Patrick J. Stover, vice chancellor of Texas A&M AgriLife, dean of the Texas A&M College of Agriculture and Life Sciences and director of Texas A&M AgriLife Research.

HLB solutions must overcome known challenges

An effective HLB treatment must avoid numerous pitfalls, Mandadi explained.

One major problem is getting a treatment to the infected inner parts of the tree. The disease-causing bacteria only infect a network of cells called the phloem, which distributes nutrients throughout a tree. Starved of nutrients, infected trees bear low-quality fruits and have shortened lifespans.

Treatments must reach the phloem to kill the bacteria. So, spraying treatments on leaves has little chance of success because citrus leaves’ waxy coating usually prevents the treatments from penetrating.

Second, while the bacteria thrive in phloem, they do not grow in a petri dish. Until recently, scientists wishing to test treatments could only do so in living trees, in a slow and laborious process.

Third, orange and grapefruit trees are quite susceptible to the disease-causing bacteria and do not build immunity on their own. Strict quarantines are in place. Treatments must be tested in groves that are already infected.

Two types of potential HLB therapies will be tested using novel technologies

The teams will be working to advance two main types of treatment, employing technologies they’ve developed in the past to overcome the problems mentioned above.

First, a few years ago, Mandadi and his colleagues discovered a way to propagate the HLB-causing bacteria in the lab. This method involves growing the bacteria in tiny, root-like structures developed from infected trees. The team will use this so-called “hairy roots” method to screen treatments much faster than would be possible in citrus trees.

In these hairy roots, the team will test short chains of amino acids – peptides – that make spinach naturally resistant to HLB. After initial testing, the most promising spinach peptides will undergo testing in field trees. To get these peptides to the phloem of a tree, their gene sequences will be engineered into a special, benign citrus tristeza virus vector developed at the University of Florida. The citrus tristeza virus naturally resides in the phloem and can deliver the peptides where they can be effective.

“Even though a particular peptide may have efficacy in the lab, we won’t know if it will be expressed in sufficient levels in a tree and for enough time to kill the bacteria,” Mandadi said. “Viruses are smart, and sometimes they throw the peptide out. Field trials are crucial.”

The second type of treatment to undergo testing is synthetic or naturally occurring small molecules that may kill HLB-causing bacteria. Again, Mandadi’s team will screen the molecules in hairy roots. A multistate team will further test the efficacy of the most promising molecules by injecting them into trunks of infected trees in the field.

A feasible HLB treatment is effective and profitable

Another hurdle to overcome is ensuring that growers and consumers accept the products the team develops.

“We have to convince producers that the use of therapies is profitable and consumers that the fruit from treated trees would be safe to eat,” Mandadi said.

Therefore, a multistate economics and marketing team will conduct studies to determine the extent of economic benefits to citrus growers. In addition, a multistate extension and outreach team will use diverse outlets to disseminate project information to stakeholders. This team will also survey growers to gauge how likely they are to try the treatments.

“The research team will be informed by those surveys,” Mandadi said. “We will also engage a project advisory board of representatives from academia, universities, state and federal agencies, industry, and growers. While we are doing the science, the advisory board will provide guidance on both the technical and practical aspects of the project.”

Project team members:

—Kranthi Mandadi, Texas A&M AgriLife Research.

—Mike Irey, Southern Gardens Citrus, Florida.

—Choaa El-Mohtar, University of Florida Institute of Food and Agricultural Sciences, Citrus Research and Education Center.

—Ray Yokomi, USDA-Agricultural Research Service, Parlier, California.

—Ute Albrecht, University of Florida IFAS Southwest Florida Research and Education Center.

—Veronica Ancona, Texas A&M University-Kingsville Citrus Center.

—Freddy Ibanez-Carrasco, Texas A&M AgriLife Research, Department of Entomology, Weslaco.

—Sonia Irigoyen, AgriLife Research, Texas A&M AgriLife Research and Extension Center at Weslaco.

—Ariel Singerman, University of Florida IFAS Citrus Research and Education Center.

—Jinha Jung, Purdue University, Indiana.

—Juan Enciso, Texas A&M AgriLife Research, Department of Biological and Agricultural Engineering, Weslaco.

—Samuel Zapata, Texas A&M AgriLife Extension, Department of Agricultural Economics, Weslaco.

—Olufemi Alabi, Texas A&M AgriLife Extension, Department of Plant Pathology and Microbiology, Weslaco.

—Sonia Rios, University of California Cooperative Extension, Riverside and San Diego counties.

—Ben Faber, University of California Cooperative Extension, Ventura, Santa Barbara and San Luis Obispo counties.

—Greg Douhan, University of California Cooperative Extension, Tulare, Fresno and Madera counties.

2021-12-06T13:51:10-08:00December 6th, 2021|

Chlorpyrifos Sales Will End in Feb.

Agreement Reached to End Sale of Chlorpyrifos in California by February 2020

The California Environmental Protection Agency announced today that virtually all use of the pesticide chlorpyrifos in California will end next year following an agreement between the Department of Pesticide Regulation (DPR) and pesticide manufacturers to withdraw their products.

“For years, environmental justice advocates have fought to get the harmful pesticide chlorpyrifos out of our communities,” said Governor Gavin Newsom. “Thanks to their tenacity and the work of countless others, this will now occur faster than originally envisioned. This is a big win for children, workers and public health in California.”

“The swift end to the sale of chlorpyrifos protects vulnerable communities by taking a harmful pesticide off the market,” said California Secretary for Environmental Protection Jared Blumenfeld. “This agreement avoids a protracted legal process while providing a clear timeline for California farmers as we look toward developing alternative pest management practices.”

Earlier this year, DPR announced it was acting to ban use of chlorpyrifos by canceling the pesticide’s product registrations. The decision follows mounting evidence, PDF that chlorpyrifos is associated with serious health effects in children and other sensitive populations at lower levels of exposure than previously understood, including impaired brain and neurological development.

At the same time, DPR and the California Department of Food and Agriculture (CDFA) have established a cross-sector working group to identify, evaluate and recommend safer, more sustainable pest management alternatives to chlorpyrifos. It will hold its first meeting this month and will hold three public workshops beginning in January.

The agreement with Dow AgroSciences and other companies means that use of chlorpyrifos will end sooner than anticipated had the companies pursued administrative hearings and potential appeals process, which could have taken up to two years. Under the settlement, the companies agreed that:

  • All sales of chlorpyrifos products to growers in California will end on Feb. 6, 2020.
  • Growers will no longer be allowed to possess or use chlorpyrifos products in California after Dec. 31, 2020.
  • Until then, all uses must comply with existing restrictions, including a ban on aerial spraying, quarter-mile buffer zones and limiting use to crop-pest combinations that lack alternatives. DPR will support aggressive enforcement of these restrictions.

To ensure consistency for growers and for enforcement purposes, DPR is applying the terms and deadlines in the settlements to seven other companies that are not part of the settlement agreement but are subject to DPR’s cancellation orders.

A few products that apply chlorpyrifos in granular form, representing less than one percent of agricultural use of chlorpyrifos, will be allowed to remain on the market. These products are not associated with detrimental health effects. DPR will continue to monitor for any exposures associated with these products.

The development of safe, more sustainable alternatives to chlorpyrifos is being supported through the current state budget, which appropriates more than $5 million in grant funding for the purpose.

  • DPR will award more than $2.1 million in grants to fund projects that identify, develop, and implement safer, practical, and sustainable pest management alternatives to chlorpyrifos.
  • CDFA will award approximately $2 million in grants to expand outreach about innovative, biologically integrated farming systems that reduce chemical insecticide inputs. Crops that have used chlorpyrifos will be a priority.
  • CDFA will also fund approximately $1.5 million in research to develop alternatives to chlorpyrifos that provide safer, more sustainable pest management solutions.

Quick facts:

  • Chlorpyrifos is used to control pests on a variety of crops, including alfalfa, almonds, citrus, cotton, grapes and walnuts. It has declined in use over the past decade as California growers have shifted to safer alternatives.
  • Use of the pesticide dropped more than 50 percent from two million pounds in 2005 to just over 900,000 pounds in 2017.
  • In 2015, DPR designated chlorpyrifos as a “restricted material” that requires a permit from the county agricultural commissioner for its application. In addition, application of chlorpyrifos must be recommended by a licensed pest control advisor and supervised by a licensed certified applicator.
  • Following DPR’s designation of chlorpyrifos as a toxic air contaminant in 2018, DPR recommended that county agricultural commissioners apply additional permit restrictions, including a ban on aerial spraying, quarter-mile buffer zones and limiting use to crop-pest combinations that lack alternatives.

###

2020-01-02T17:41:57-08:00January 3rd, 2020|

Western Growers Statement on California DPR Ban on Chlorpyrifos

Tom Nassif: CA Farmers Face the Most Stringent Regulations in the World

By Cory Lunde, Western Growers

In response to the recent announcement that the California Department of Pesticide Residue (DPR) is acting to ban the use of the insecticide chlorpyrifos, Western Growers President and CEO Tom Nassif issued the following statement:

“California farmers are universally committed to the safety of their food, the health of their workers and communities, and the sustainability of their land. At every turn, they strive to achieve efficiencies in their use of resources like water, fertilizer, and pesticides and seek to minimize both the human and environmental impacts of these inputs.

immigration reform

Tom Nassif

“California farmers also face the most stringent regulatory environment in the world, one that often limits their access to many of the tools still available to farmers elsewhere in the U.S. and in foreign countries, including certain types of pesticides. Indeed, over the last 20 years, California regulatory actions have removed several of the most important crop protection tools farmers rely on to fight pests and diseases.

“With … [the] announcement that DPR will initiate the cancellation of chlorpyrifos, one of the most widely studied and globally approved insecticides, California farmers now stand to lose yet another arrow in their quiver—without effective and ready replacement tools—making their quest to grow the safest, healthiest and most abundant food supply in the world even more difficult.

“California farmers are resilient, but the long-term viability of our farms in California depends on proper support from the Administration and renewed cooperation of the state’s regulatory agencies, especially in light of the many other unique and expensive regulations that place California farmers at a growing competitive disadvantage.”
2021-05-12T11:05:03-07:00May 22nd, 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.”

2021-05-12T11:01:49-07:00April 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.

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

Curly Top Virus Light In 2018

CDFA Surveys Predict Curly Top Vectored by Leafhoppers

By Patrick Cavanaugh, Editor

Curly top virus is a common disease in California. In its worst years, entire fields have been lost to curly top in the foothills of the Central Valley, and it can infect a variety of plants from a total of 44 plant families as well as 300 individual species.

Curly top commonly affects tomatoes, peppers, beets, spinach, potatoes, and beans, as well as a variety of weeds. A common characteristic of curly top is stunting of the plant as well as curling and twisting of the leaves, where it gets its name, curly top. Leafhoppers are the main vector of the virus.

Currently, the CDFA conducts a yearly curly top prediction where they monitor numbers and the leafhopper population as well as the prevalence of the virus to give a scope of what the upcoming year might look like.

“Curly top virus was very low in 2018 as predicted—based on the amount of virus carried by the leafhoppers and the leafhopper population,” said Bob Gilbertson, Plant Pathologist, Department of Plant Pathology at UC Davis.

“We hope that CDFA will continue to carry out the leafhopper screening for the virus and for the population so growers get a prediction of what the curly top incidents will be the coming year,” Gilbertson said. “It’s good that we can tell growers when there’s going to be a bad curly top year so they can implement additional strategies.”

These strategies include changing where they’re going to plant a field or using timed insecticides, particularly systemic insecticides like the new Verimark (From FMC) insecticide to manage curly top.

“We’ve already found that that material can slow down the spread of curly top in a field,” Gilbertson explained. “So in a year where it’s predicted to be bad—high populations of leafhoppers carrying high amounts of the virus—then you as a grower would then want to consider using some of these insecticide approaches.”

2021-05-12T11:01:51-07:00January 4th, 2019|

2018 Cotton Crop Proceeding Well

Late Season Pests Can Be a Challenge

By Patrick Cavanaugh, Editor

The 2018 cotton harvest will be starting in the southern part of the Central Valley later this month, and some growers will be facing pressure from pests.

California Ag Today recently spoke about the topic with Dan Munk, a UC Cooperative Extension Farm Advisor in Fresno County specializing in irrigation crop nutrient management and cotton production systems.

“The crop looks very good and loaded with cotton bolls. We don’t have a lot of boll losses, and that’s a real positive thing, so very excited about the potential for fairly high yields in the 2018 season. The biggest concern right now is pest management, press pressures as we approach the latter part of the season,” Munk explained.

The main issue this time of year is the honeydew that pest leave on the cotton. Honeydew is the exudate extracted by the insect as it feeds on the leaves.

“Because we have the bolls on the plant that have opened, we now have exposed lint and need to protect that lint from stickiness that’s created from whitefly and the aphid honeydew, which is basically the added sugars that those insects that feed on the leaves of the plant, and they excrete them and deposit them on the lint,” Munk said.

Munk explained that the big concern right now is dealing with pest pressures in terms of whitefly and aphid—both sucking insects. “The problem right now [is] where we’re seeing pest pressures—particularly from whitefly as we get later in the season—will build in many fields.

There are several approaches to controlling whitefly and aphids. One is to deal with the eggs that they produced. And then there’s a certain class of materials to deal with the eggs.

“There’s another class of materials that deal with the juveniles—that early form of the insect—and then there are ways to control the adults,” Munk said.

“A number of insecticides have been applied to deal with those various levels of insect populations based on the individual field situation,” he explained.

2021-05-12T11:01:53-07:00October 3rd, 2018|

Citrus Psyllid Control Strategy Changes

Reducing Sprays in Areas, and Border Nets

By Jessica Theisman, Associate Editor
beth_grafton-cardwell

Entomologist Beth Grafton-Cardwell

Huanglongbing, vectored by the Asian Citrus Psyllid, (ACP) is the dreaded disease that has nearly wiped out the Florida citrus industry and is a potential problem for citrus growers in California. California Ag Today recently met with Beth Grafton-Cardwell, a UC Cooperative Extension Specialist. She specializes in integrated pest management; she discussed new strategies for the control of HLB.

“We have been surveying grower orchards in southern California and following how pesticide sprays are working, and I’m going to make some new recommendations on how to handle the populations down there,” said Grafton-Cardwell, who is also the director of the Lindcove Research and Extension Center. “Some regions of Southern California are easier to control psyllids than others. The pesticide treatment is less intensive due to the desert climate. San Diego is one of the areas that is less intensive due to the drier trees making them more hardened off, with less new flushes, where ACP is attracted.”

“There are other areas of southern California where the trees flush continually, providing great places for the psyllids to lay eggs, and that is where treatments are going to have to intensify,” she explained.

Areas such as Ventura, Riverside, and San Bernardino have to increase their treatments in the fall for better control.

And researchers are currently studying new prevention and control methods.

“Texas A & M has been looking at erecting net-like borders around the orchards because the psyllid tends to go to the edges,” Grafton-Cardwell said.

They want to treat the netting with yellow strips of sticky paper that would attract and/or apply insecticides to kill the psyllid.

“Our research is showing that often the infestation starts on the borders. Growers may have to intensify the number of treatments, but they don’t have to treat the entire orchard,” Grafton-Cardwell said. “Growers might be able to fight the psyllid with only treating the trees on the outer edges.”

2021-05-12T11:05:12-07:00May 10th, 2018|

Mycotoxins are Serious Business

Sanitation Fights Mycotoxin Infections

By Jessica Theisman, Associate Editor

In nature, there are fungal metabolites called mycotoxins, and some of them can infect crops. However, certain cultural practices can eliminate them. California Ag Today recently spoke with Bob Klein, manager of the California Pistachio Research Board, based in Fresno, about the topic.

“We see mycotoxins as a result of fungal infection that comes from the Navel Orange Worm. It is damaged predominantly, and if a crop is contaminated with possible mycotoxins, such as one known as Aflatoxn, it can hurt exports. Over 70 percent of our crop is exported, and some of our major markets are very sensitive to a mycotoxin contamination,” Klein said.

“The best programs start with orchard sanitation. Many growers are lax on sanitation or spend low amounts of money,” he explained. “Those who are frugal are spending $200-250 an acre on sanitation, and so growers need to be prepared for that.”

As far as insecticide applications, look at the growers’ data, not what is published in replicated field trials.

“More sprays are better than fewer sprays,” Klein said.

2021-05-12T11:01:56-07:00February 15th, 2018|

Pyrethroid Review is Important

Be Thoughtful on Pyrethroid Review Comment Page

By Patrick Cavanaugh, Farm News Director 

California Ag Today has continued coverage on the pyrethroid class of insecticides, which were under review by the EPA. The critical industry comment deadline has been moved to honor before July 7th this year. California Ag Today spoke with David Haviland, an entomology farm advisor with UC Cooperative Extension Kern County about his philosophy on commenting regarding the pyrethroid class of materials.

“From my perspective, please don’t go on there and just say, ‘We need pyrethroids.’ What they really need to know is what importance do these pyrethroids play to that particular commodity on that particular farm? What’s being done to make sure that the risk from those products are mitigated? One of the concerns of pyrethroids is if they can move off-site into waterways. That’s a legitimate concern. All those things need to be taken into account and then reviewed,” he said.

An easy website to go to comment without that complicated government URL is simply Defendbifenthrin.com.

 

2017-06-01T00:13:05-07:00May 30th, 2017|

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