Red Scale Challenges Citrus

Besides HLB, Red Scale Challenges Citrus

By Charmayne Hefley, Associate Editor

While much of the talk in the citrus industry is about how to fend off Huanglongbing (HLB) disease, one of the most devastating citrus diseases, Dr. Beth Grafton-Cardwell, director of the University of California Agriculture and Natural Resources Lindcove Research and Extension Center, reinforced that HLB isn’t the only pest that can overtake California’s citrus orchards.

Grafton-Cardwell explained how last year’s warm winter led to an increase in the California red scale, Aonidiella aurantii, population. “Normally we have cold conditions that kill off the younger instars of the scales and [basically] restarts the system. But we didn’t really have any low temperatures last year, so the scales didn’t go into their usual hibernating phase. They just kept cranking out crawlers and adding in an extra generation or two of production. So the higher number of scales on the trees made it much more difficult for the growers to control.”

Grafton-Cardwell explained while it is difficult to speculate whether this coming year will yield another large population of the California red scale, “We have already received more moisture as a result of seasonal rainfall, which should help hinder the pest. Hopefully we’ll get some cooler weather conditions too–not freezing because citrus groves don’t like freezing temperatures–but cold enough to knock out some of the scales and get the population back under a manageable level,” she said.

Nevertheless, despite the challenges that California red scale can cause, Grafton-Cardwell said, overall, citrus growers need to keep their focus on the fight against the Asian Citrus Pysllid (ACP), Diaphorina citri, and its ability to spread HLB. “Growers need to start thinking in terms of: California has the [HLB] disease and it’s going to start spreading in southern California soon,” Grafton-Cardwell said. “What do we do to prevent it from spreading up here into the San Joaquin Valley?”

Photo source: “Life Stages of California Red Scale and Its Parasitoids,” UC ANR Publication #21529, by Forster, Lisa D.; Robert F. Luck; and Elizabeth E. Grafton-Cardwell; with photos by L. Forster and M. Badgley)

Patrick Cavanaugh2021-05-12T11:03:04-07:00January 20th, 2016|

USDA Pesticide Data Program Report Confirms Food Safety

USDA Pesticide Data Program Report Confirms Food Safety:

More than 99 percent of sampled food tested below allowable pesticide residue levels!

The U.S. Department of Agriculture (USDA) has confirmed again in its annual report that American consumers can focus on the nutritional benefits of conventional and organic produce without concern for pesticide residues. Over 99 percent of fresh and processed food available to consumers tested below allowable pesticide residue levels, as detailed in the 24^thPesticide Data Program (PDP) Annual Report released on January 11, 2016 by the USDA Agricultural Marketing Service (AMS). Only .36 percent [0.36%] of the products sampled through the PDP had residues above the U.S. Environmental Protection Agency (EPA) established tolerances, giving consumers plentiful options to meet their daily nutritional needs.

“Today’s consumers can choose from food produced with a variety of farming methods and necessary crop protection strategies and be confident that it will sustain and enrich their families’ lives,” stated Jay Vroom, president and CEO of CropLife America (CLA). “Across the nation, our growers continue to use the most advanced crop protection technology available to target specific crop threats. From precision agriculture to integrated pest management, farmers in the heartland, the plains, coastal areas and everywhere in between are pushing forward with the best ways to produce food for their communities and for the country.”

PDP researchers tested a total of 10,619 samples of fresh and processed fruit and vegetables (8,582 samples), oats (314 samples), rice (314 samples), infant formula (1,055 samples), and salmon (354 samples). To ensure the samples were representative of the U.S., researchers collected data in a variety of states throughout different times of the year. The findings support the Dietary Guidelines for Americans 2015-2020, recently released by USDA and the U.S. Department of Health, which encourage consumers to eat more fruits and vegetables.

“With rapid advancements in computing technology, the space for developing new ways to fight agricultural threats is increasing exponentially,” stated Dr. Janet E. Collins, senior vice president of science and regulatory affairs at CLA. “Consumers have a number of options at the grocery store, thanks in large part to the work of the scientific community involved in research and development, the companies that are manufacturing products, and America’s farmers and ranchers. The 2014 PDP report demonstrates again that, with the sound science-based regulation of pesticides and commitment from the industry, farmers and other stakeholders, we can reach toward making sure that every American, no matter their wallet size or geographic location, can access healthy food.”

A 2012 report from CLA demonstrates that crop protection has made healthy food more financially accessible to the American consumer, providing a 47.92 percent savings in overall grocery bills for a family of four in the U.S.¹ In addition, increased agricultural production, due to advanced pesticides, has created an additional 1,040,661 jobs generating more than $33 billion in wages—all while decreasing the need for tillage operations, thereby reducing fossil fuel use by 558 million gallons per year.

Recent reports from the United Nations also show that an increasing number of people worldwide have gained access to healthy food. Over the past 25 years, the number of people worldwide who are hungry has declined from one billion to about 795 million, or about one person out of nine—which means that 2 billion people have avoided a “likely state of hunger” given the global population increase of 1.9 billion people since 1990-92.² Multiple factors have contributed to the decrease in global hunger, including the integration of family farmers and small holders in rural areas into well-functioning markets for food, inputs and labor.

The PDP was established in 1991 for the purpose of collecting data on pesticide residues found in food. Information collected by the PDP is sent to the EPA to help the agency conduct important dietary risk assessments. The USDA also uses this data in the development of integrated pest management objectives. Since the PDP program was initiated, 109 different commodities have undergone testing. A complete version of the 2014 Annual Summary is available at www.ams.usda.gov/pdp.

¹ CropLife America. The Contributions of Crop Protection Products to the United States Economy.

² Food and Agriculture Organization of the United Nations, the International Fund for Agricultural Development and the World Food Program. State of Food Insecurity in the World 2015.

Established in 1933, CropLife America (www.croplifeamerica.org) represents the developers, manufacturers, formulators and distributors of plant science solutions for agriculture and pest management in the United States. CropLife America’s member companies produce, sell and distribute virtually all the crop protection and biotechnology products used by American farmers. CLA can be found on Twitter at @CropLifeAmerica. CLA supports CropLife StewardshipFirst.

California Ag Today2021-05-12T11:03:05-07:00January 13th, 2016|

Protecting California Citrus from ACP

By Charmayne Hefley, Associate Editor

[embedvideo id=”ZWgOOjpxwE8″ website=”youtube”]

California’s $2.2 billion fresh citrus industry that supplies 85 percent of the nation’s fresh citrus is currently healthy and vibrant despite the background threat of the Asian Citrus Psyllid (ACP), according to Kevin Severns, a citrus grower in Sanger, CA; general manager of the Orange Cove-Sanger Citrus Association, a cooperative citrus packing house in eastern Fresno County; and chairman of California Citrus Mutual.

“We’re quite concerned about it,” Severns said about the ACP—a tiny bug that is a known carrier or vector of “huanglongbing” (HLB), a devastating, incurable disease of citrus trees that has already demolished the citrus industry in Florida. “We’ve been able to keep the bug at bay to this point,” Severins continued, “at least here in the Central Valley, but we’re very concerned about it. There are a lot of issues to be concerned about with this bug.”

California has taken note of the devastation of Florida’s industry, Severns said, and is taking steps to ensure the safety of California’s citrus. “Having gone to Florida with many of our citrus growers,” Severns explained, “I heard Florida growers tell we must control the bug. So we’re trying to keep this bug at bay and not allow [the infestation] to expand. We’ve had varied success in different areas of California, but so far, we’ve been able to keep the bug’s expansion here in the Central Valley to a minimum. We continue to have finds from time to time, but we haven’t yet had an explosion of the population of the ACP.”

Severns said, “We have a very successful partnership with the California Department of Food and Agriculture (CDFA).” While trapping ACP is critical, he emphasized the importance of enlisting the help of residential folks with citrus in their backyards to get involved in the conversation, to look for this pest, and to join in the fight. “The trap is very limited in its ability to pick up ACP, so it’s very important that we have visual surveys in which growers and homeowners actually go out and look at their trees for the bug.”

Severns said current measures against the spread of the ACP is helping to buy time for researchers to find a cure for HLB. “We realize every place on earth where the ACP has gone, eventually has been followed by HLB,” Severns said, “so we’re trying very hard to buy time and give our researchers and scientists a chance to come up with a solution to this disease—whether it is a resistant type of citrus variety or a cure for the trees.”

Preventing the spread of ACP and HLB, from commercial citrus growers to residential citrus growers, will require that everyone works together. To learn more, go to CaliforniaCitrusThreat.org or contact your local Ag Commissioner.

_________________

Did you know, the historical time period establishing the California citrus industry is known as the “other” California Gold Rush? (Source: California Citrus Mutual)

_________________

Patrick Cavanaugh2021-05-12T11:05:58-07:00January 12th, 2016|

Grower-PCA Communication is Critical

By Laurie Greene, Editor

Emily Symmes, UC Cooperative Extension Integrated Pest Management Advisor, Butte County, is amazed at the professionalism of growers and Pest Control Advisors (PCAs). “I deal directly with growers and land managers, as well as crop advisors and pest control consultants” said Symmes, “and everyone has so much to do out there, so grower-PCA communication is critical. Sometimes it is amazing how they get it all done. I feel lucky, as I get to focus on the pest management and other production activities throughout the season,” she noted.

Symmes maintains there has to be a lot of communication back and forth between the growers and PCAs and herself. “And within each question there is a deeper conversation,” she elaborated, “but it can get lost in the shuffle of running from one thing to the next. Everything is very time sensitive in agriculture; we don’t have control over weather and things that tend to drive pest population cycles.”

“So within each of those key pest management questions, there is a subset of questions:

How do we know that it is time?
Are we doing the right thing at the right time?
Are we using the right materials?
Are we considering the big picture?’”

“The other big key ingredient is follow-up—evaluating:

How did we do?
Did the treatment work?
Did it cause any potentially negative impacts that we weren’t aware of?
Did we have to come back and do something additional (after-the-fact)?
More questions about the treatment, time, and material.”
PCA Responsibilities (CA DPR)

And on any California Department of Pesticide Regulation (DPR) recommendation, there is a question before the last signature line, ‘Have you thought of any other alternatives before you make this application?’ IPM practitioners sometimes misunderstand this to mean, ‘Well they don’t want us to treat.’ But it is really an acknowledgement that we know how important all of our management tactics are,” Symmes noted.

“Cultural practices are important, pesticides are important, but knowledge is really the key ingredient. Growers and PCAs are knowledgeable, have explored the alternatives and know what is going on in this particular orchard block they are signing this legal document for. Honestly, I think we do a great job.”

“I think California has done a fantastic job with this,” said Symmes,”but is there room for improvement? I think there always is.”

California Ag Today2021-05-12T11:05:59-07:00January 7th, 2016|

More Rain, More Fungi, More Use for Multiuse Fungicides

With More Rain, More Fungi, More Use for Multiuse Fungicides

By Patrick Cavanaugh, Deputy Editor

With spring rains, many vegetables, tree fruits, grapes and nuts succumb to fungi pressure. However, during the past few years, only trivial amounts of spring rain have moistened California’s soil and lulled farmers to abandon their vigilant watch for fungi proliferation. But now, the strong likelihood of El niño-driven wet weather this spring could catch growers off-guard.

“We have an El niño coming that has already been tagged, ‘Too big to fail,’ which will bring a lot of rain. So it’s really important for folks to think about switching gears this year on their pest management mindset. With more rain, comes more fungi disease. We always see really high pressure disease years with rain,” said Kate Walker a technical services representative with BASF Corporation on the Central Coast, who advises use of a multiuse fungicide product already on hand.

Anthracnose in Strawberries, UC Statewide IPM Project

Anthracnose in Strawberries (Source: UC Statewide IPM Project

Strawberries, in particular, are vulverable to fungi. “We have heard from our strawberry growers,” said Walker, “that these fungal diseases are always present in California, but they vary significantly in their severity year-to-year depending on the weather,” noted Walker.

“One major disease that accompanies higher moisture, Anthracnose, often called leaf, shoot, or twig blight,” Walker explained, “results from infection caused by the fungus Colletotrichum. I’ve heard some growers have not experienced Anthracnose issues in 10 years,” said Walker. “As it emerges and becomes more problematic in strawberries, farmers really need to know which types of fungicides to use to manage this and other diseases.”

“It is very important for farmers and PCAs to walk through and scout their fields for disease,” Walker said, “and when they identify one, to become very aggressive with their fungicide management program. So, as representatives for BASF, we are lucky to have multiuse fungicide products available to control these diseases, such as Merivon Fungicide.”

Walker noted Merivon has two modes of action, “so it is very broad-spectrum. Typically we position Merivon in California for use on powdery mildew and Botrytis, but what we seldom talk to growers about is its utility for Anthracnose. We see a lot more Anthracnose in Florida and on the East Coast due to the increased rains; whereas, it usually doesn’t come through every year in California. So it is good to for farmers and PCSs to know that the product with which they are familiar for use in Botrytis, is also very effective with other issues, like Anthracnose.”

Walker offered, “Another very common disease that flourishes with increased rain, Rhizopus, occurs post-harvest, after the berries are picked up from the field. Again, Merivon has utility for Rhizopus as well, so growers don’t have to change or reinvent their program to manage these diseases.”

Walker said, “Rhizopus is an airborne bread mold. It is very common in the air and in the soil, so anytime a fruit or a nut is exposed to the spores blowing in the wind, it is vulnerable to infection with this disease.”

California Ag Today2016-05-31T19:27:02-07:00December 4th, 2015|

Armyworms Invade Rice

Luis Espino: Armyworms Invade Rice

By Charmayne Hefley, Associate Editor

Larva of the armyworm, Mythimna unipuncta.
Photo by Jack Kelly Clark, UC IPM.

Farmers face many threats to their crops on a daily basis. Luis Espino, rice farm advisor UC ANR Cooperative Extension, Colusa County, said rice farmers are on the lookout for two caterpillar infestations during the year when armyworms invade rice fields. “The first one occurs sometime in June,” Espino said. “At that time all they do is just eat the foliage, and you can usually see it when you walk into a field. Nevertheless, the rice has a very good capacity to recover from that type of injury.” Espino’s UC Rice Blog explains it is difficult to accurately estimate yield losses due to early armyworm damage because it can reduce tillering, delay the crop, and cause uneven maturity.

“Heading” occurs when the rice plant prepares to enter its reproductive phase. The first sign, called the ‘booting’ stage, is when the leaf stem that conceals the developing panicle bulges. Then the tip of the developing panicle emerges from the stem and continues to grow. Rice is said to be at the ‘heading’ stage when the panicle is fully visible. Flowering begins a day after heading has completed. As the flowers open they shed their pollen on each other so that pollination can occur. Flowering can continue for about 7 days. (Source: Rice Development, Ricepedia.)

“The second infestation usually occurs in mid- to late-August when the rice is heading out,” Espino said. “At that time, armyworms can feed on the panicles, [causing the kernels to dry before filling], resulting in blanks [without kernels to harvest] on the panicles and broken panicle branches. That’s when armyworms are more important.”

Espino said that the first infestation this year was relatively large, making it harder for the treatments to control the armyworms as they devastated the rice fields. “There were some areas in fields where the rice was down to the waters,” Espino said. “so all the foliage was consumed, and sometimes only a little stem was left standing.”

During the second armyworm infestation, however, Espino said the rice fields were not as badly affected as they had been in the first attack. “We did see some fields with armyworm injury,” Espino said,“ and some farmers had to treat their fields. The numbers were just so big that the treatments were not controlling them.”

Resources:

UCANR/CA Rice Blog, “Estimating armyworm injury.”
Ricepedia

Patrick Cavanaugh2016-05-31T19:27:09-07:00September 30th, 2015|

Celery Management Research

Andre Biscaro on Celery Management Research to Improve Water and Nitrogen Use

By Charmayne Hefley, Associate Editor

Ongoing research continually improves the agriculture industry. Andre Biscaro, agriculture and environmental issues advisor at the University of California, Division of Agriculture and Natural Resources, Cooperative Extension, Los Angeles and Ventura Counties, described current trials in celery management research, sponsored by the California Celery Research Advisory Board.

“We’re monitoring water and nitrogen use based on best management practices,” Biscaro said. “We evaluate ‘best management’ practices using the soil nitrate quick test. That gives us a really good estimate of how much nitrogen is in the soil, and we can accomplish the test in just about an hour.” The trial also incorporates data from weather stations to calculate the amount of applied water.

“This trial and research actually monitors the amount of water and nitrogen we’re using and how much yield we’re getting under various best management scenarios,” Biscaro said, “and compares our practices to what the grower usually does.” Ultimately, the trial will help determine the yield of a celery field using best management practices, and how much water and nitrogen are required to achieve that yield.

Biscaro said the grower he has been working with to conduct the trial was already highly successful with soil and water management in the specific celery field under study. “He really knew what he was doing, and the nitrogen management was quite decent as well. So I believe there are opportunities for improvement in the industry, but the grower was actually doing quite well in this particular field I monitored.”

Patrick Cavanaugh2016-05-31T19:27:09-07:00September 25th, 2015|

New UC IPM Program Director

Jim Farrar Named Director of UC Statewide IPM Management Program

By Pam Kan-Rice, UCANR Assistant Director, News and Information Outreach

Jim Farrar has been named director of the Statewide Integrated Pest Management Program for the University of California’s Division of Agriculture and Natural Resources. He will begin as new uc ipm program director on Oct. 1.

UC IPM works with growers and residents to protect human health and the environment by reducing risks caused by pests and pest management practices.

Farrar is currently director of the Western IPM Center, where he has served since 2013. He succeeds Kassim Al-Khatib, UC IPM director since 2009, who is transitioning to a UC Cooperative Extension specialist position located in the Department of Plant Sciences at UC Davis. There Al-Khatib will focus on his research in weed management.

“UC IPM is a widely recognized national leader in integrated pest management,” Farrar said. “I am excited to continue efforts to make IPM the standard practice for managing pests in agriculture, communities and natural areas in California.”

Prior to joining the Western IPM Center, Farrar was a professor of plant pathology in the Department of Plant Science at California State University, Fresno for 12 years.

At Fresno State, Farrar received three teaching awards. He taught courses in plant pathology, plant nematology, diagnosis and control of plant diseases, crop improvement, aspects of crop productivity, mycology, sustainable agriculture and advanced pest management. His research centered on fungal diseases of vegetable crops, including management strategies for cavity spot of carrot. During his Fresno State tenure, he served four years as chair of the Department of Plant Science and a year as interim chair of the Department of Food Science and Nutrition.

From 1995 to 1997, Farrar taught in the Botany Department at Weber State University in Ogden, Utah. At Weber State, he conducted research on rock cress plants infected with a rust fungus that causes false-flowers. This rust is closely related to a species that is a potential biological control agent for dyer’s woad (Isatis tinctoris), an invasive weed.

Farrar has published scientific papers, extension newsletter articles, and articles in agricultural industry magazines. He also wrote a chapter in the book Tomato Health Management and five disease descriptions in the book Compendium of Umbelliferous Crop Diseases. He recently completed a three-year term as senior editor for feature articles in the journal Plant Disease and was senior editor for the online journal Plant Health Progress for three years. Farrar is a member of the American Phytopathological Society and the Pacific Division of the American Phytopathological Society.

The Wisconsin native completed his Ph.D. in botany and B.S. in plant pathology at the University of Wisconsin, Madison, and his M.S. in plant pathology at UC Davis.

California Ag Today2016-05-31T19:28:05-07:00September 10th, 2015|

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.

Patrick Cavanaugh2021-05-12T11:06:01-07:00June 3rd, 2014|

ALERT: Immediate Action Needed for Thrips/TSWR

Source: Neil McRoberts

For those who have water and tomatoes:

Thrips numbers have increased rapidly in the southern arm of the Central Valley and Tomato spotted wilt virus (TSWV) has been reported in all of the areas we monitor,” according to Neil McRoberts, Assistant Professor, Plant Pathology Department, UC Davis.

There are numerous reports of TSWV symptoms in crops from Stanislaus County down to Fresno and Kings County particularly around the Huron area.

The current risk in Fresno County is high and we are recommending that growers who plan to use an insecticide program against thrips/TSWV take immediate action. The current mini heat wave will accelerate thrips development slightly and further bump up thrips numbers.

If you are planning to use an insecticide program against thrips/TSWV this season, you should target the next generation of thrips (generation 3). If it is not possible to arrange for treatment in time to catch generation 3, target generation 4. Delaying treatment until later in the season will be much less effective at preventing damage from TSWV. Coordinated spraying across large areas has an additional effect on thrips populations because it makes it difficult for them to avoid treatment by migrating.

Generation 3 adults are projected to peak on May 17th. Sprays applied in the 14-day period before this peak date will check generation 3 and delay further population build-up and TSWV spread. This means you need to take immediate action.

Generation 4 adults are projected to peak on June 11th. Sprays applied in the 14-day period before this peak date will check generation 4 and delay further population build up and TSWV spread. Treatment in the 14 days immediately following the generation 3 peak date will also be effective.

The current risk in the Merced area is high and we are recommending that growers who plan to use an insecticide program against thrips/TSWV take immediate action. The current mini heat wave will accelerate thrips development slightly and further bump up thrips numbers.

Generation 3 adults are projected to peak on May 22nd. Sprays applied in the 14-day period before this peak date will check generation 3 and delay further population build-up and TSWV spread.

Generation 4 adults are projected to peak on June 16th. Sprays applied in the 14-day period before this peak date will check generation 4 and delay further population build up and TSWV spread. Treatment in the 14 days immediately following the generation 3 peak date will also be effective.

The current risk in eastern San Joaquin County is lower than in other southern Counties, but we think a precautionary approach is best. The current mini heat wave will accelerate thrips development slightly and further bump up thrips numbers.

If you are planning to use an insecticide program against thrips/TSWV this season, you should target the next generation of thrips (generation 3). If it is not possible to arrange for treatment in time to catch generation 3, target generation 4. Delaying treatment until later in the season will be much less effective at preventing damage from TSWV. Coordinated spraying across large areas has an additional effect on thrips populations because it makes it difficult for them to avoid treatment by migrating.

Generation 3 adults are projected to peak on May 28th. Sprays applied in the 14-day period before this peak date will check generation 3 and delay further population build-up and TSWV spread.

Generation 4 adults are projected to peak on June 22nd. Sprays applied in the 14-day period before this peak date will check generation 4 and delay further population build up and TSWV spread.

The current risk in Kings County is high and we are recommending that growers who plan to use an insecticide program against thrips/TSWV take immediate action. The current mini heat wave will accelerate thrips development slightly and further bump up thrips numbers.

If you are planning to use an insecticide program against thrips/TSWV this season, you should target the next generation of thrips (generation 3). If it is not possible to arrange for treatment in time to catch generation 3, target generation 4. Delaying treatment until later in the season will be much less effective at preventing damage from TSWV. Coordinated spraying across large areas has an additional effect on thrips populations because it makes it difficult for them to avoid treatment by migrating.

Generation 3 adults are projected to peak on May 22nd. Sprays applied in the 14-day period before this peak date will check generation 3 and delay further population build-up and TSWV spread. This means you need to take immediate action.

Generation 4 adults are projected to peak on June 14th. Sprays applied in the 14-day period before this peak date will check generation 4 and delay further population build up and TSWV spread. Treatment in the 14 days immediately following the generation 3 peak date will also be effective.

The current risk in western San Joaquin County is lower than in other southern counties, but we think a precautionary approach is best. The current mini heat wave will accelerate thrips development slightly and further bump up thrips numbers.

If you are planning to use an insecticide program against thrips/TSWV this season, you should target the next generation of thrips (generation 3). If it is not possible to arrange for treatment in time to catch generation 3, target generation 4.

Delaying treatment until later in the season will be much less effective at preventing damage from TSWV. Coordinated spraying across large areas has an additional effect on thrips populations because it makes it difficult for them to avoid treatment by migrating.

Generation 3 adults are projected to peak on May 28th. Sprays applied in the 14-day period before this peak date will check generation 3 and delay further population build-up and TSWV spread.

Generation 4 adults are projected to peak on June 22nd. Sprays applied in the 14-day period before this peak date will check generation 4 and delay further population build up and TSWV spread.

The web resource for integrated management of Western Flower Thrips and Tomato Spotted Wilt Virus in the California Central Valley contains two tools to help in disease risk management:

A Field Risk Index tool uses simple information about field locations, land use, and agronomy to calculate a risk category for tomato crops. This tool can be used before planting or early in the season to get a heads up about the general risk to a crop from TSWV.

A thrips population projection model, driven by degree-day accumulation at several Central Valley locations, aids in projecting when thrips generations are hatching, developing, and adult numbers are peaking. This information is used to issue regular updates and provide broad guidelines for timing insecticide sprays to keep thrips numbers low enough to prevent TSWV from spreading.

The research behind these tools was supported by the California Tomato Research Institute (CTRI)

The model was developed in Collaboration with Dr. Len Coop of Oregon State University’s Integrated Plant Protection Center (IPPC). The IPPC developed and hosts the USPEST web service which is a multi pest multi model tool that provides information on pest development and disease risk for the Contiguous 48 US states using a network of weather stations.

Patrick Cavanaugh2021-05-12T11:03:06-07:00May 4th, 2014|