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
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.

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

ACP Control Protocols At World Ag Expo Feb. 13

World Ag Expo Seminar: Asian Citrus Psyllid and Huanglongbing – Regulatory Compliance Update and Treatment Protocol

News Release

If you’re attending the World Ag Expo, the Citrus Pest & Disease Prevention Program encourages you to attend a seminar on Feb. 13 to learn about regulatory protocols relating to Asian citrus psyllid and Huanglongbing quarantines, the proper mitigation requirements for transportation of bulk citrus, and recommended treatment options for ACP in commercial citrus groves and residential citrus trees from industry experts.

During the seminar, Keith Okasaki of the California Department of Food and Agriculture will discuss the regulatory protocols for moving bulk citrus fruit in the state of California. Dr. Beth Grafton-Cardwell will discuss the University of California’s recommended treatment options for suppressing and controlling the Asian citrus psyllid in commercial citrus groves and residential citrus trees.

This seminar is free to attend with a World Ag Expo attendee ticket or exhibitor pass.

Asian Citrus Psyllid and Huanglongbing – Regulatory Compliance Update and Treatment Protocols Seminar

Wednesday, Feb. 13

Noon – 1 p.m.

Location

Seminar Trailer 1 in the Seminar Center

The Seminar Center is near South Gate 15, at the corner of U Street and Expo Lane.

Preventing the Spread of ACP

Valley Citrus Growers Continue Vigilance

By Jessica Theisman, Associate Editor
ACP
USDA ACP Cooperative Program Map (Source:
California Citrus Pest & Disease Prevention Program)

The spread of Asian Citrus Psyllid (ACP) continues to be a looming threat for Central Valley citrus growers as it vectors Huanglongbing (HLB), a disease that destroys citrus trees. Greg Douhan, a University of California Cooperative Extension Tulare County citrus farm advisor reported to California Ag Today recently that, “There have been so many people onboard really working at this from multiple angles, and we’re in the eradication mode. We want to make sure the insect doesn’t get established in the San Joaquin Valley.”

“If one were to look at a map of ACP infestation in California [such as CDFA Quarantine Maps and California Citrus Pest & Disease Prevention Program Threat map], they may consider it to be endemic in the Los Angeles area. Rest assured that anytime ACP is found in a trap, the CDFA sprays everything in that area within 400 meters.”

Douhan said the Valley is on high alert to find ACP in traps. “

If researchers discover a cluster of finds in any particular area, we manage some spray programs and try to get all the growers to do a coordinated effort in order to try to combat it,” he said.

SaveOurCitrusIn addition, the SAVE OUR CITRUS app is a free USDA iPhone app to report and identify the four leading citrus diseases: citrus greening, citrus canker, citrus black spot and sweet orange scab. Report your symptoms, upload a photo, and citrus experts will respond.

So far, the practices have been working well.

“I think most of the growers are very well informed,” Douhan said, “and are taking this very seriously because it is this their livelihood.”

Fighting Asian Citrus Psyllid On and Off the Farm

Fighting ACP on Farms and Residential Areas Critical

By Hannah Young, Associate Editor

Pests and diseases are as prominent as ever not only for California farmers but in residential areas as well. California Ag Today recently spoke with Rick Westcott, a senior sales rep for Bayer Crop Science, about preventative materials for pests and diseases and the importance of controlling the spread of those diseases, particularly Asian citrus psyllid.

Westcott explained that the advantage of Movento, a powerful insecticide, is that it is systemic, it’s applied early, and it will translocate throughout the entire tree.

“It’s both phloem and xylem movement, so it’ll go down into the roots and then back up so it constantly recirculates within the plant,” Westcott said. “That’s what gives it the longevity of control.”

In citrus trees, Movento typically takes about 65 to 70 days to start working after circulating through the plant which helps with the longevity of the product, Westcott added.

Although Movento is not used specifically for Asian citrus psyllid, it has proved to aid in controlling the pest.

Westcott said Movento is currently being used against citrus red scale and applied during pedal fall along with thrip sprays, which farmers are applying anyway.

“It will take care of your red scale, your early red scale spray, and of course, because it also controls Asian citrus psyllid, it’s a bonus to do that too,” Westcott said. “Then the other thing that they’re doing with the thrip spray as well for katydid control, which is also an issue in citrus at that thrip timing.”

By patrolling and monitoring for ACP, the spread of HLB can also be controlled.

“The key is to keep the ACP at the lowest level possible or zero if that’s possible. [The] fortunate thing for us in the San Joaquin Valley is the fact that we do a lot of spraying for other pests throughout the year that almost everything that we put in the tank happens to also control ACP at the same time,” Westcott explained.

Westcott said that this is the reason we have not seen a huge outbreak of ACP in the San Joaquin Valley, unlike other parts of California.

“The problem isn’t in any commercial grove at this point, but it’s all residential,” Westcott continued. “It’s all concentrated in the residential areas, so there are certain products that you can use an ag that you can’t use there, but most of them, fortunately, you know, they have a label for both residential and agriculture, so they do crossover to stop them there so they don’t get here.”

HLB is still posing a threat in California, but most specifically in the Los Angeles area.

“The total amount of trees currently that are infective with HLB in the counties of LA, Orange and Riverside County is 645. And then if you compare that from a year ago: a year ago, there were only 73 trees that they had infected, and it’s changing every day,” Westcott said.

Research Nets Going Over Citrus Trees To Prevent Huanglongbing Disease

Blocking Psyllids Carrying Disease is Key

By Jessica Theisman, Associate Editor

Beth Grafton-Cardwell is the director of the Lindcove Research Extension Center in Tulare County and research entomologist based out of the University of California, Riverside. She recently told California Ag Today that there is work being done on installing a net structure to protect trees from Asian Citrus Psyllids, which spread the deadly Huanglongbing disease. Texas A&M researchers are installing net structures on the edge of groves to block psyllids from coming into an orchard.

Psyllids have a preference for borders. These nets could have yellow sticky strips of material with an insecticide on it, so there would be an attract and kill process.

Beth Grafton-Cardwell

Other research is looking at netted structures that will completely enclose the citrus trees.

“Researchers are going to construct a completely enclosed net structure to grow the citrus trees in a block at Lindcove,” Grafton-Cardwell said. “We will study how well one can grow citrus under the screen so there could be the ultimate protection against pests and diseases.”

“The mother trees and increased trees have to be grown under the screen, but the field trees do not necessarily have to be,” she said.

Cold temperatures in the winter to protect the citrus from the psyllid.

“The cold temperatures hardened off the tissue, which makes it hard for the psyllid to find any place to lay eggs, and they probably cost some mortality to the psyllid,” Grafton-Cardwell explained.

Most outbreaks are in Southern California. Los Angeles, Orange County, and a few trees in Riverside.

“Prevention is working and there are fewer outbreaks in the Central Valley,” Grafton-Cardwell said.

Dr. Mark Hoddle and Dr. Kelsey Schall (both from UC Riverside) have been monitoring backyard situations. They are researching the release of beneficials such Tamarixia and other generalist predators like Syrphid flies.

“They have been reducing psyllids by about 70 percent in the backyards, and that’s really good news,” Grafton-Cardwell said.

Could CDFA’s ACP Control Policy Devastate Our Citrus Industry Like Florida’s?

Citrus Industry is Fired Up Over Softened ACP Control Policy

By Patrick Cavanaugh

 

It seems that CDFA officials are giving up on controlling the Asian Citrus Psyllid (ACP) in Central California citrus growing areas! It sure looks like it.

Ever since the May 12 ACP trappings in the Lindsay area of Tulare County, there has been a major back-step in what has been an aggressive mandatory spray program to control any possible live psyllids within an 800-meter radius around the trap.

Now CDFA is suggesting that the spray programs should be voluntary and only 400 feet around the trap find.

According to Joel Nelsen, president of the Exeter-based California Citrus Mutual, “The conversation relative to the change in eradicating or treating for the ACP came about with a discussion between a few members of the scientific community and the department.”

“Frankly, the industry was unaware of this possible change in the program. When it was first released to the AG commissioner, it shocked everybody–is my understanding,” Nelsen said.

“And as a result, last Friday afternoon, the executive committee members from our pest and disease management committee had a very direct conversation with senior leadership of the CDFA. I understand that the conversation was extremely candid, somewhat emotional; if the industry to is going to be supporting a program to the tune of 15 million dollars, they want a say in how the program is run. And evidently, the Department of Agriculture is making some subjective decisions that we don’t believe are appropriate.”

“From my perspective, there were mistakes made at the onset of this program that we had to learn from; and if we don’t take seriously—psyllid control, psyllid control, psyllid control!—we’re going to end up in the same type of quandary that our colleagues in Florida, Texas, Mexico and even Brazil are in.

Too many psyllids, an endemic population, some of which will contract citrus greening disease and eventually contaminate citrus trees, could devastate central California’s $2 Billion industry. “If we even allow one psyllid to continue to foster a population, then we have failed at our effort. And so from the perspective of Citrus Mutual, we are in an eradication mode,” Nelsen said.

“We are in a position in which we can find isolated psyllids and treat, and we are in position where continuous trapping and tapping (with bats and trays in searching for psyllids) and intensive trapping is not finding an endemic population. So for the department to argue that the population is endemic, its a ‘what if’ scenario that we don’t think is appropriate.”

Nelsen said that the pushback by his pest and disease management committee might have made a difference. “I haven’t received anything, but I think that conversation last Friday afternoon yielded some intended results. There’s a reconsideration, and I give a lot of credit to the industry members who stood up the department; but until it happens, its not real,” he said.