Pyrethroid Review Deadline Nearing

Pyrethroid Review Commenting Deadline is March 31

By Patrick Cavanaugh, Farm News Director

The EPA is reviewing the pyrethroid class of crop protection materials and it’s concerning the Ag industry, which often turns to the materials as part of an integrated pest management strategy – recommended by the University of California.

David Haviland – an entomologist with UC Cooperative Extension Kern County – said he is not too concerned with the EPA review.

“Every pesticide should be periodically reviewed to make sure that all new information about a product gets reconsidered. Our ability to test for products changes over time. Our experience with products changes over times. The role of products changes over time, so a re-review is warranted. I don’t have any concerns with that,” Haviland said.

Of course, the big question is what is the current role of pyrethroids in the grower’s toolbox?

“It absolutely has a role. The best way to manage pests we know is through integrated pest management, and integrated means using lots of different tactics. Sometimes, there’s a way to control a pest completely with biological control, sometimes there’s a cultural control, but there are cases where pesticides are needed,” Haviland said.

“There’s a time and a place for a very soft surgical strike against one-species pesticide and there’s also a time and a place for a product that can kill two or three or four different pests at the same time. Sometimes, those broader spectrum products are the only ones available for certain pests,” Haviland explained.

“Pyrethroids fit that role as the last group of broad spectrum products that are effective on a wide range of pests, particularly with organophosphates, which is being phased out of most crops,” Haviland said.

There is time to comment on this EPA review – and this time expires March 31, so it’s critical for anyone who needs these pyrethroids as an IPM strategy to go to www.defendbifenthrin.com and post a comment.

Patrick Cavanaugh2021-05-12T11:05:42-07:00February 27th, 2017|

EPA Reviews Agricultural Pyrethroids

Pyrethroid Products Reviewed

By Brian German, Associate Broadcaster

Pyrethroids are synthetic chemical insecticides that are included in more than 3,500 registered products, with many of those being used in agriculture. Every 15 years, the Environmental Protection Agency is required by congress to review all registered pesticides. They received their first-ever review evaluating how they impact fish and aquatic plants.

John Cummings is the Registration and Regulatory Affairs Manager for FMC, a diversified chemical company that has been serving the agricultural community for over a century. “We are very concerned with the content of that risk assessment – that they have identified that there is high-risk concerns to certain aquatic organisms, not necessarily fish or anything like that, but small aquatic organisms,” Cummings said.

The underlying purpose of these kinds of reviews is to ensure public safety, especially when reviewing products used in ag production. “They’ve done a very high level, simple, cursory risk assessment that has identified these concerns,” Cummings said.

During the past decade, the use of pyrethroids has increased, as the use of organophosphate pesticides continues to decline. That is due to their higher toxicity to birds and mammals when compared to pyrethroids. Cummings expressed his concern regarding the data that the EPA bases their decision on. “There’s been other actions by EPA recently around the use of the best available data and the best science around risk assessment. … The EPA should be using the best science to make the right regulatory decisions while protecting the environment,” Cummings said.

Through their industry consortium, the Pyrethroid Working Group, FMC is in the process of putting data together that they hope the EPA will take into consideration. Cummings explained that their research will “make it more real world while still conservative and protecting the environment. It’s more real world and typical of how these products are used.”

Pyrethroids are a broad-spectrum insecticide that have shown tremendous success in controlling a variety of different insects considered to be economically important to the ag industry. “Pyrethroids are a very important element of both integrated pest management as well as resistance management. Growers today are facing very complex insect control problems, and it’s necessary to have many tools in the tool box,” Cummings said.

“I think EPA needs to understand how important it is to consider the benefit of these to production agriculture as well as society, in feeding the world,” Cummings concluded.

The public comment period for the EPA’s risk assessment has been extended to March 31st.

Ag Stakeholders are urged to comment at http://www.defendbifenthrin.com

Patrick Cavanaugh2021-05-12T11:05:43-07:00February 26th, 2017|

Pesticide Expert Brian Leahy Has Respect for Weeds

Brian Leahy Reminds Growers About DPR’s Mission

By Patrick Cavanaugh, Farm News Director

Brian Leahy is the Director of the California Department of Pesticide Regulation (DPR). Leahy was among the first organic rice growers, and he said he had a very intimate relationship with weeds. “I have lot of respect for weeds, and a lot of respect for weed management. So, with that, we know that weeds are an important challenge in agriculture and in our over society,” he said.

Brian Leahy

Leahy noted that herbicide solutions are very cost effective when they work, but they come with challenges. “And those challenges include the Department of Pesticide Regulation. We are a science-based organization. We have about 400 employees; 300 of them are classified as scientists. We have well over 100 Ph.D.s, we have people with graduate programs from three different continents.”

“We are a very science-based organization. We have very good scientists, but we also incorporate what we call Risk Management. So myself, along with my chief Deputy Director Christopher Reardon, take a look at what the scientists do, and we make risk management decisions. I think it is an important role,” Leahy said. “We use a lot of data, and we are very good at collecting data. Our core mission, of course, is to protect the environment and human health. That is at the center.”

Leahy noted that farm workers and farmers have the closest contact to pesticides, as do folks who are helping with cleaning, such as custodians and janitors.

“But that is our main mission, and it includes the community,” he said. “California has done a remarkable job of building on farmland and adjacent to farmland. We have schools, houses, hospitals, daycare centers, all very close to farmland that uses pesticides. So we have focused on protection of human health as well as how we use pesticides.”

“I would really emphasize farm worker protection, the long-term studies on pesticides show that the folks most at risk are the handlers,” Leahy said.” Of course the other big thing we are supposed to do is protect our environment. That is actually getting to be a much more challenging endeavor. It includes our water quality, it includes pollinators, and off site movement.”

“The third component of our mission has been to foster reduced-risk pesticides. That can take all kinds of forms. We have been engaged in landscaping in this state, because we know which plant in your front yard or backyard is going to determine which pesticides and herbicides you need to use,” Leahy said. “IPM tells you to look at your environment, so we are encouraging that. We are looking at cultural practices and ways to reduce the reliance on pesticides. So that is a part of our mission as well.”

One the most important relationships DPR has is with the county ag commissioners. “Recently, I spent the day with the County Ag Commissioner of Monterey County – a very challenging position,” Leahy said. “We met a couple of Board of Supervisors, we met with labor folks, we met with public health officers, and we met with the superintendent of the school district, which has a lot of schools in the middle of farms. She also has a student population where 11 percent are homeless, some of the poorest students in the state in her school district. She is trying to ensure that her children are safe as they learn. And her relationship with her County Agricultural Commissioner is very important.”

“These County Agricultural Commissioners put about 300 biologists in the field to do pesticide enforcement and education. Enforcement is very important, education is even more important. So, we give them somewhere around $27 million a year to run their pesticide program. They do a very good job. So that is a very important relationship we have,” Leahy said.

Leahy explained that DPR and CDFA have a very vigorous pesticide residue-testing program here in the state. “We test more products than the Federal government does. We look at what might be our biggest challenges and found … cactus from Mexico with residues of Organophosphate materials, which [were] banned in the ’60s. If you ate them, it would make you feel like you had the flu. So we have begun to target what we think are some of the most problematic crops in countries,” he said.

“We are starting to do enforcement, going after retailers and brokers. They have no business selling food that will make people sick,” Leahy said. “It is not a good business practice, and we need to make sure they get that message.”

“It also helps us with enforcement. On a very rare occasion, we will find a California grower who used a pesticide that should not even be on that crop,” Leahy said. “If that happens, we will go in and have them destroy the crop, fine them and get them to realize that it is probably wise, probably in their best interest. But it is a very important tool. What we have found is the most important thing is simply working together. We build very strong relationships with the farmers, the farm workers, the registrant community, with all the stakeholders. And there are a lot of stakeholders in pesticide.”

Leahy said that pesticides are kind of a challenging business because what they are doing is changing human behavior. “If we want to ensure that if you are producing food, you have the tools that you need; we simply want to make sure that those tools do the job and don’t keep moving and doing harm to your neighbors, yourself or the environment. But this collaborative approach is the only one that works, and we want to do that; a lot of active listening.”

Product registration is a very important part of the DPR program. Leahy said that introducing a new active ingredient into the market is a half-a-billion dollar endeavor. “There are years when we don’t see a new active ingredient. And other years, maybe you see four, which is a big number. Not a lot of new herbicides coming into the marketplace. And every time something comes in, there is a change, either a new AI or a even a new use. There are a lot of people looking at that,” he said.

“I can tell you that the water community looks very closely at pesticides. Every time we try to introduce something new, something to control ants or something to control weeds, they want reassurances that it is not going to end up in the water supply, in the storm water, in the drinking water, all of it. The water community are our partners, so we have to listen to them.”

“Then we have all of the stakeholders like the Center for Biological Diversity and all those folks that really care about environmental issues, and they will sue you very quickly if they feel like there is going to be a challenge to one of their critters. So it is challenging to get in new chemistry. This is kind of a cautionary tale that the ag industry must be sure to use materials correctly. Resistance management should always be on our minds,” he noted.

“A number of things have made us successful. I talked about the registration process, looking at the chemistry, and getting a really good idea of how that chemistry is going to behave in the human body and the environment before we put it in.

“Looking at it as we go, we have an incredible system to collect data. We try to capture every pesticide illness in the state. We work hard to do that. We listen to people who have complaints and issues and we follow up and so we can direct our science to determine how to make it better,” Leahy noted.

Recently, the National Academy of Sciences looked at the DPR program. According to Leahy, one of the things that they said was that DPR was “incredible at mitigation, which basically means that they figure out how that pesticide moves off-target.”

“We have made an amazing amount of progress. Society is always asking us to go further, and we will. This is a plug once again to remind you that weeds and insect pests are quick at adapting, that resistance is a real issue. We don’t want to lose tools because they are hard to replace. So mix it up,” Leahy said.

“As we all know, there is no silver bullet for resistance – there are multiple ways of preventing resistance -so just keep that in mind. … We want to keep the tools that we have, but we want to be able to use the new ones and the core of that is a prevention program,” Leahy said.

Patrick Cavanaugh2021-05-12T11:02:00-07:00January 30th, 2017|

Pyrethroids Under Review

EPA Reviewing Pyrethroids

Ag Industry Urged to Comment

By Patrick Cavanaugh, Farm News Director

The pyrethroid insecticide class is in review for ecological risk assessment by the Environmental Protection Agency. John Cummings, Registration and Regulatory Affairs Manager at chemical company FMC believes that the assessment could have a large impact on producers.

Agricultural leaders have urged all to comment on the need to keep this chemistry available. Please share your thoughts by clicking here.

“At FMC, we’re very concerned with the content of that risk assessment that they’ve identified that there’s high risk concerns to certain aquatic organisms, not necessarily fish or anything like that, but small aquatic organisms,” Cummings said. “Our concern, as a company who manufactures these pyrethroids, which are used in California, is that the EPA has not used the best science that’s available. They’ve done a very high level simple cursory risk assessment that has identified these concerns.”

More than 3,500 registered insecticides contain a pyrethroid. Many pyrethroids are household products and are not limited to agricultural usage.

“Our hope, as a pyrethroid company, is that EPA will consider better data which FMC and our industry consortium, the Pyrethroid Working Group, are developing to incorporate into this risk assessment. We need the EPA to look at the real world of how these products are used. With that, that risk assessment should look much better and remove any of these risk concerns that EPA currently has,” he said.

There have been other actions conducted by the EPA around the use of the best available data and the best science in risk assessment. These kind of precedents will impact production agriculture in the U.S. as well as California.

“EPA should be using the best science to make the right regulatory decisions while protecting the environment,” Cummings said. “It is very important, and I think it’s important, too, that EPA understand the implications of taking a conservative approach and making regulatory decisions that may impact production. I think EPA needs to understand how important it is to consider the benefit of production agriculture in feeding the world.”

It is important to keep many pest control products available to prevent the overuse of one product. Pesticide resistance is a growing problem, and it is essential that producers are able to keep all of their options open.

“Pyrethroids are a very important element of integrated pest management, as well as resistance management. Growers today are facing very complex insect control problems,” Cummings said.

“It’s necessary to have many tools in the toolbox to control insects. We have multiple classes of chemistry, but based on regulatory decisions, the EPA could potentially remove some of these important tools, which puts more pressure on other tools that remain in the toolbox, and insects may become resistant to many of these tools,” Cummings explained.

“Pyrethroids are a critical broad spectrum insecticide that are very affordable and control a lot of different insects that are economically important,” Cummings said.

Bob Klein, the manager of the Pistachio Research Board, agrees that pyrethroids are essential to pest management.

“The use of pyrethroids goes hand-in-hand with the use of soft chemicals like the growth regulators, or some of the neonicotinoids, or some of the other new chemistries we have,” Klein said.

“It guards against resistance development in those other chemicals as well. The inclusion of pyrethroids by the University of California, and many other Integrated Pest Management manuals, shows that pyrethroids are an important part of any IPM program. IPM programs are the way that people control pests in their orchards,” Klein said.

The risk assessment is currently open for comment and will remain open until March 31^st.

Comment: Here

Patrick Cavanaugh2021-05-12T11:05:43-07:00January 26th, 2017|

Citrus Trucks Will be Tarped

Tarped Citrus Trucks Will Fight ACP

By Melissa Moe, Associate Editor

In the ongoing battle against Asian Citrus Psyllids, an insect that is known to vector the fatal Huanglongbing disease in citrus, the California Department of Food & Agriculture has issued a new regulation to require trucks to be tarped when moving citrus. This regulation will be phased in and permit holders will be notified by CDFA.

Joel Nelsen, president of the California Citrus Mutual, explained that the regulation will prevent the spread of this vector-transmitted pathogen. “What we discovered is that psyllids were flying towards fruit sitting in trucks and bins as they were being transited from Southern California to the San Joaquin Valley, because of the aromas that the fruit gives off,” he said.

Fruit is not considered to be a vector of Huanglongbing since ACP can only vector the disease through leaves and twigs. However, these pests are catching rides on trucks all over the state on the fruit that was considered to be relatively safe.

“What happens is the Asian Citrus Psyllid is attracted to the aroma coming off of the orange, and it flies towards it thinking it’s going to find a food source,” Nelsen said. “Well, it rides around on the orange for a couple of hours, until it figures out that there’s no green waste or twigs attached to that fruit, and then it flies off.”

Fruit that is being transported from Bakersfield to Fresno could be taking these hitchhiking pests anywhere along Highway 99. While on this joyride, they could go up and down 5, across 126, or across 10 from Southern California into the San Joaquin Valley. News of new ACP finds have been right along these traveling corridors.

“We discovered that we may be part of the problem in helping Asian Citrus Psyllids spread, or have a hitchhiker role,” Nelsen said. “We made that determination as a result of some research done by the University of California. We ended up talking to growers at seven different grower meetings; several hundred in total were participating in the discussions. We all came to the conclusion that it’s going to cost us some money now, but it’s better than costing us the industry later.”

Patrick Cavanaugh2021-05-12T11:00:46-07:00January 9th, 2017|

Better Navel Orangeworm Spray Coverage

Navel Orangeworm Sprays Tough to Target

By Patrick Cavanaugh, Farm News Director

Naval orangeworm is the number one pest in almonds and pistachios, and there’s a lot of research going on to find ways to manage this pest. One important strategy is timely sprays, but Joel Siegel, a research entomologist with USDA Ag Research Service in Parlier, CA, said that it’s tough to get that spray on target.

Joel Siegel

“Spraying for naval orangeworm is learning to live with loss. Many years ago, my professor told me to assume that 90 percent of what you put out never goes where you want it to go. I didn’t know that he was being an optimist when he told me that,” he said.

To confirm this, Siegel set up a controlled experiment sponsored by DuPont. “Using the best setup of spray rigs at two miles per hour, we’re basically getting 10 percent of what we calculated in the tank was actually getting on the nut,” he said. “Then if you add the difficulty of saying, you want to get it in the suture on an early split almond, you’re probably getting about two percent of what’s in your tank actually on that suture zone, so you’re dealing with a 98 percent loss.”

Siegel said the spray is getting in the tree, but not on the nut or the suture of the nut. “I’m talking about just getting on target. It’s getting on the leaves, it’s getting on the bark, it might be getting on the ground.”

Siegel noted that it’s actually better to spray at night, when the naval orange worm adults are flying. “That way, some of the drift can actually contact the adults. The other advantage of night spraying is that the humidity is higher, so you’re not getting that loss of having the droplets evaporate.”

Patrick Cavanaugh2021-05-12T11:02:00-07:00December 29th, 2016|

California Ag Today Seeks Guest Writers, Story Suggestions

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California Ag Today2021-05-12T11:17:11-07:00December 12th, 2016|

Record Enrollment at UC Davis College of Agriculture and Environmental Sciences

UC Davis College of Agriculture and Environmental Sciences Really Rocks!

By Patrick Cavanaugh, Farm News Director

Helene Dillard, dean, UC Davis College of Agriculture and Environmental Sciences, is pleased with the big numbers of students attending the top-ranking College of Agricultural and Environmental Sciences.

Helene Dillard, dean, UC Davis College of Agriculture and Environmental Sciences

“It’s really rocking,” said Dillard. “We’re doing very, very well. We have one of the largest numbers of incoming students ever in the entire university. Our College has peaked out its 7,300 undergraduates. We’ve never had that many at one time.”

Why the increased interest in studying agriculture? Dillard said, “We think what’s moving that needle is that everyone is interested in food. They are interested in agriculture. And they are really interested in that intersection between agriculture and the environment. We have a record number of students that just cannot wait to come on board. We are really thrilled with how smart they are and how eager they are to learn.”

Among the many courses offered by the College, Dillard said Animal Science classes are probably among the most popular. “But of course, beer classes and the coffee class are really popular too. But right now, I’m seeing tremendous interest in agricultural economics and in animal science, to become veterinarians and ranchers, plus specific academic interest in poultry and sheep.”

“Again, those are all things that UC Davis does, so we’re really excited. We’re also seeing a lot of interest in plant sciences, more on that sustainable and food systems and our viticulture and enology program’s growing as well.

Recent Graduate Program Rankings for UC Davis College of Agriculture and Environmental Sciences and related disciplines include:

1st in agricultural sciences (Thomson Reuters ScienceWatch 2011)
2nd in agriculture and forestry (QS World University Rankings 2016)
2nd in agriculture worldwide (U.S. News & World Report’s “2016 Best Global Universities”)
1st in ecology and the environment (Thomson Reuters ScienceWatch 2011)
1st in food science and nutrition (Thomson Reuters ScienceWatch 2010)
1st in plant science (U.S. News & World Report’s “2016 Best Global Universities”)
1st in animal science (U.S. News & World Report’s “2016 Best Global Universities”)
1st for veterinary science (QS World University Rankings 2016)
1st among the nation’s veterinary schools (U.S. News & World Report’s “Best Graduate Schools” 2016)
Between 1st and 15th among 44 programs in nutritional biology (National Research Council 2010)
4th in environment/ecology (U.S. News & World Report’s “2016 Best Global Universities”)
Between 1st and 7th in Entomology among 28 programs (National Research Council 2010)
Between 5th and 29th among 116 programs in plant biology (National Research Council 2010)
Between 7th and 42th among 116 programs in plant pathology (National Research Council 2010)
13th in environmental engineering worldwide (QS World University Rankings 2016)
29th in environmental engineering worldwide (2016 Global Ranking of Academic Subjects, ShanghaiRankings)

(Source: University of California, Davis, Graduate academic program rankings.)

UC Davis College of Agriculture and Environmental Sciences

California Ag Today2021-05-12T11:17:11-07:00December 7th, 2016|

Modifying Rootstocks to Fight, Prevent Pierce’s Disease

Scientists Help Grapevines Double-team Pierce’s Disease

By Patrick Cavanaugh, Farm News Director

The glassy-winged sharpshooter is a flying insect that vectors a fatal grapevine malady known as Pierce’s Disease. Scientists are conducting volumes of research to fight this insect and reduce disease infection on vines. Moreover, scientists are studying methods to prevent the spread of Pierce’s Disease on winegrapes in California entirely.

California grapevine

Ken Freeze is the outreach coordinator for the California Department of Food and Agriculture (CDFA) Pierce’s Disease Glassy-winged Sharpshooter Board (PD/GWSS) as well as an account director at Brown-Miller Communications. On behalf of the PD/GWSS Board, Freeze communicates with winegrape growers who pay the Board an assessment to conduct research. Freeze explained ongoing research and how research funds are being spent.

FIGHTING PIERCE’S DISEASE

Could introducing pectin into grapevines, help prevent that bacteria, Xylella fastidiosa, from entering the vine? Freeze said, in a recent field trial, “scientists found five different genes that when placed in a rootstock, put either a molecule or a protein up into an unmodified scion that in one way basically stops the bacteria from moving around,” he said.

“For instance, one of the genes comes from the pear,” said Freeze. “I think we’re all familiar with pectin. A lot of plants produce pectin naturally; grapevines are not one of them. By modifying a rootstock with this pear gene, when the bug comes and injects the bacteria into the plant, the pectin literally gums it up and it can’t move around.”

An unmodified plant injected with bacteria by the glassy-winged sharpshooter, turns to another strategy. “When the bacteria population reaches a certain point, [the plant] releases a protein that causes the bad bacteria to stop moving around. However, in grapevines, it is too late when that signal comes; the plant is already dead. By modifying the rootstock to automatically generate that same protein when the bacteria enters the plant, the bacteria shuts down,” said Freeze.

Winegrapes

Freeze said scientists are seeing that these strategies are working quite well. “What scientists are actually doing now is stacking these genes, two by two, in the rootstock. Now each root will produce two different ways to shut down the bacteria. If for some reason in the future the bacteria figures out a way to overcome one of those ways, chances are it won’t figure out how to overcome both of them.”

PREVENTING PIERCE’S DISEASE

Dr. Andy Walker, a UC Davis professor and geneticist in the Department of Viticulture and Enology, has been working for years on rootstock that could block Pierce’s Disease from entering the vine. “He’s already released 14 different varieties to the Foundation Plant Services as well as three different rootstock that are resistant to Pierce’s Disease,” said Freeze. “The best varieties will be released to nurseries probably next year. Then from there [nurseries will] basically start growing them and taking orders from winegrowers.”

Freeze noted that other field trials are continuing. “We have field trials for a benign strain of Pierce’s Disease. It is like giving plants a smallpox vaccination, only it is the bacteria. That is on its way to commercialization. In the future, you might actually order your new vines from the nursery pre-infected with the bacteria that would normally cause [Pierce’s Disease]. But in this case, it will not cause it,” said Freeze.

CDFA Pierce’s Disease Glassy-winged Sharpshooter Board (PD/GWSS)

CDFA Pierce’s Disease Glassy-winged Sharpshooter Board (PD/GWSS) Interactive Forum

CDFA Pierce’s Disease Control Program

UC Davis Department of Viticulture and Enology

UC Davis Foundation Plant Services

California Ag Today2021-05-12T11:02:00-07:00December 2nd, 2016|

Improved Huanglongbing Detection in Citrus Trees

Projects Underway for Better Huanglongbing Detection in Infected Trees

By Patrick Cavanaugh, Farm News Director

The big problem with Huanglongbing Disease (HLB), also known as citrus greening, is that an infected tree, despite having no visual symptoms, could quietly be a massive reservoir of HLB. The main vector, the Asian Citrus Psyllid (ACP), could easily pick up HLB from that tree and spread the disease throughout the orchard.

Currently, the main push to contain the possible spread of HLB is by controlling ACP. Yellow sticky traps are positioned near every commercial orchard in California, as well as near non-commercial trees in neighborhoods. Finding a psyllid on a trap triggers mandatory spray programs to help eliminate all psyllids in the area.

Neil McRoberts, associate professor of plant pathology, UC Davis

“Yes, one of the most critical questions in managing in HLB is the trees can be infected for a long time before you can visually see the ACP there,” said Neil McRoberts, an associate professor of plant pathology, University of California, Davis.

“There is a group of scientists, funded by the Citrus Research Board of California (CRB), working on different early detection methods. Those are methods where you would be able to tell the tree was infected before you could see the tree is infected,” said McRoberts.

The CRB funded field trials in Texas over the last few years that have narrowed the field of competitors to two or three techniques. The CRB will continue to fund the two leading contenders in that race to determine the leading early detection technology.

In the first technique, researchers analyzed all the microbes that live on a non-infected leaf surface and studied how that profile of microbes changes when the tree gets infected. Detecting a change in microbe profile could indicate the tree is not as healthy as it should be.

“Researchers take the microbes that live on an infected tree, extract the DNA from those microbes and run the DNA through a sequencer. The sequencer identifies which types of microbes are there,” he said.

McRoberts said sampling for microbes is easy. Researchers use an industrial-sized swab on the leaf surface. “You literally clean the leaf surface with the swab until it’s squeaky clean, put that swab in a bottle and send it to a lab. When it gets to the lab, they extract the DNA out of it and the rest of the process happens from there.

A female Tamarixia radiata laying egg on an ACP nymph. (Photo by J. Lotz). Courtesy of Citrus Research Board

In selecting which trees should undergo microbe swabbing, McRoberts noted that the ACPs tend to attack the groves from the outer edges, inwards. “At different times of the day, the light will be on different edges of the grove depending on where the sun is and how warm it is. You can target your sampling towards the places where you’re more likely to find it, but still, finding those initial little infections is tough.”

The second method is a technique called metabolic profiling. A newly infected tree starts to produce different proteins and other chemicals in response.

Still another research strategy is analyzing things that stay in the tissue. “There’s a change in the profile of metabolites in the tree. If you run those metabolites through a mass spectrometer, the mass spectrometer will spit out a profile. You can tell the difference between a healthy profile and an infected profile,” McRoberts said.

“This is how the dogs come into the picture. Everybody knows that citrus has an odor. When the trees are infected, the profile of the chemicals and the composition of that odor change. We can’t smell it, but a very sensitive electronic detector device can sometimes pick it up. Remarkably, dogs can pick it up. We think that’s what happening with the canine detectors; they’re picking up some change in the smell of the trees.”

McRoberts said that dogs are amazingly accurate in detecting trees with HLB disease. “The best that we can tell from the trials involving dogs, the false positive rate is less than 1 in 1,000. I’m very confident with the detector dogs,” McRoberts said.

Featured photo: Adult Asian citrus psyllid (Photo by J. Lewis). Courtesy of Citrus Research Board

Citrus Research Board of California (CRB)

UC Davis Department of Plant Pathology

California Ag Today2021-05-12T11:02:00-07:00December 2nd, 2016|