Pests and Diseases

Science Advisory Report Posted

The California Department of Food and Agriculture‘s (CDFA) Asian Citrus Psyllid (ACP) and Huanglongbing (HLB) Ad Hoc Science Advisory Panel (SAP) is a group of scientists selected by the Secretary to provide scientific advice to the Department to ensure that they are using the best science available when developing program policy and protocols.

These scientists consist of experts from states that have already experienced the sequence of events associated with ACP/HLB infestation, as well as California-based scientists with local knowledge to ensure a diverse perspective.

The panel met in December 2013 and was tasked with providing recommendations on a series of non-regulatory questions vetted by CDFA.

This report contains the list of questions and the answers from the ACP-SAP. In addition, the report contains the SAP’s comments and recommendations for consideration in the development of ACP/HLB programs in California.

Among the many questions answered in the report, here are a few:

What is the appropriate size of treatment areas around ACP find sites in eradication zones under a variety of scenarios?
Would it be beneficial to freeze dry leaves from asymptomatic, VOC positive trees for future analysis, when technology improves?
With most of the ACP detections in Tulare County being on traps placed on poles rather than within the canopy, should we change trap placement for the ACP program?
On March 23, 2014 we will be 2 years without a HLB detection in California. What should be our exit strategy?

For a copy of the letter, click here.

If you have any questions or concerns, please do not hesitate to contact the Citrus Program Manager, Victoria Hornbaker at 916-654-0317 or via email at Victoria.Hornbaker@cdfa.ca.gov.

Patrick Cavanaugh2016-05-31T19:38:09-07:00March 19th, 2014|

Citrus Showcase Had Strong Showing

Citrus Showcase News

Area-Wide ACP Spraying To Start Soon

By Patrick Cavanaugh, Editor

The 2014 California Citrus Showcase in Visalia, hosted by the Exeter based California Citrus Mutual, brought a record crowd.

“It was the largest event we have had in our 15 years,” said Joel Nelson, President of the California Citrus Mutual, the organization that hosts the annual event. “We had about 100 exhibitors and about 650 people for lunch, and roughly 1,000 growers who meandered though the entire show throughout the course of the day,” Nelson said.

There were also six workshops that focused on the Asian Citrus Psyllid, the vector of the fatal HLB disease, water quality and even GMO research to help find HLB resistant citrus stock.

“What we wanted to do was give our growers a bit of optimism,” said Nelson. “Our citrus industry has been hit with so many challenges, not withstanding the ACP/HLB issue, the disease that is ravaging Florida; the freeze in December and now the drought conditions.”

“We wanted the industry to be aware that there are opportunities to fix these problems that are facing our industry, and I think that the growers left here much more positive than when they came in,” said Nelson.

Joel Nelson, President of California Citrus Mutual, with Felicia Marcus, Chair of the State Water Resources Control Board

Some of the highlights of the half-day event included:

The keynote speaker for the inaugural Citrus Showcase Breakfast was Felicia Marcus, Chair of the State Water Resources Control Board. “This is a scary and uncertain drought, and it is going to be painful,” Marcus said.

“There is no question that we would not be where we are today if we had more storage,” Marcus said. “We are concerned with climate change when we could be facing the regular loss of half of our storage…snow in the mountains.”

She also said that nitrates in the ground water are a legacy issue.

Another big topic centered on what can be done to suppress the ACP, which will help prevent HLB infected trees.

The San Joaquin Valley Citrus Industry has been discussing area-wide treatment of orchards, on top of the mandated treatments when a psyllid is found.

Kevin Severns

“As it stands right now, there would be logical areas where geographically it would make sense to have that as a treatment zone,” said Kevin Severns, a grower and the new Chairman of California Citrus Mutual.

“There will be area captains in each of the zones, such as a grower or other person well-known in the area. They would work with an area-wide coordinator, and the state-wide coordinator will be responsible for coordinating treatment,” Severns said.

The spray timing would be when new growth flushes occur on citrus trees, a time when the ACP is attracted too.

Attendees also heard from Mike Sparks, President of the Florida Citrus Mutual, who painted a grim picture of what has happened to the Florida citrus industry and described its uncertain future.

“The losses due to HLB over the last seven years have been more than $70 million, said Sparks. “Before HLB disease hit us, the Florida Citrus industry was at 815,000 acres. Today the acreage is at 525,000. And we are losing orange juice processing plant infrastructure due to the low volume, pegged at only 115 million boxes, down from 133 million boxes last season.”

“Every orchard in the state is infected and growers are doing every thing they can to reduce ACP numbers and remove HLB-infected trees,” said Sparks.

Mike Sparks

There is particular concern for orchards that have been abandoned.

“The cost of production in order to fight ACP with sprays continues to go up, while production goes down. We know this is not sustainable,” said Sparks.

“Over the years, Florida citrus growers have had to deal with freezes, citrus canker, and even powerful hurricanes that have wiped out orchards. At least those orchards could be replanted and production would resume. HLB, is a far different threat. It has put growers to their knees,” Sparks said.

Patrick Cavanaugh2016-05-31T19:38:51-07:00March 7th, 2014|

COMPREHENSIVE CALIFORNIA AVOCADO PRODUCTION COURSE

Apply for “AVOCADO PRODUCTION FOR NEW GROWERS” – a 6-Week Course

Attention new and beginning California avocado growers,

Dr. Gary Bender, Ph.D., is offering a new six-week course entitled “Avocado Production for New Growers.” The course will be held on Thursday afternoons and conclude with a Saturday trip to the UC Cooperative Extension high-density trial and commercial grove.

The course is sponsored by UC ANR and UCCE-San Diego and supported by the California Avocado Commission.

The course schedule is as follows:

January 30 — Introduction to Agriculture in San Diego County, History of Avocado Production in California

February 6 — Botany, Flowering, Varieties, Harvest Dates, Rootstocks

February 14 (Friday) — Irrigation Systems, Irrigation Scheduling, Salinity Management

February 20 — Fertilization, Organic Production

February 27 — Insect and Mite Control, Disease Control

March 6 — Canopy Management, Tree Spacing, Frost Management

March 13 — Ag Waiver Water School Training

March 15 (Saturday) — Field trip to UC Cooperative Extension high-density trial and commercial grove

Because space is limited, register online early or mail in the registration form. The fee is $105 and includes class materials and a bonus publication. For more information, contact Cristina Lomeli at 760.752.4724.

Patrick Cavanaugh2016-05-31T19:41:11-07:00January 23rd, 2014|

USDA CREATES MULTI-AGENCY EMERGENCY RESPONSE FRAMEWORK TO COMBAT HLB

USDA Providing $1 million to Jump Start Citrus Response Framework

The U.S. Department of Agriculture TODAY announced the creation of a new, unified emergency response framework to address Huanglongbing (HLB). This new framework will allow USDA and its many partners to better coordinate HLB resources, share information and develop operational strategies to maximize effectiveness.

“USDA listened to the citrus industry’s request for more urgency and greater coordination on the response to HLB and is implementing an emergency response structure,” said Secretary Tom Vilsack. “To jump start this initiative and affirm our commitment to industry, USDA is also providing $1 million to be used in support of research projects that can bring practical and short-term solutions to the growers in their efforts to combat this disease.

Through the Specialty Crop Research Initiative of the Farm Bill, USDA has provided $9 million in research to blocking the ability of insects to spread HLB to healthy trees. We need Congress to quickly pass a new Farm, Food, and Jobs Bill that continues to support this kind of research to protect a crop worth more than $3 billion in the last harvest.”

The new framework will bring together USDA’s Animal and Plant Health Inspection Service (APHIS), Agricultural Research Service (ARS) and National Institute of Food and Agriculture (NIFA), along with state departments of agriculture and the citrus industry into a Multi-Agency Coordination (MAC) Group for HLB. It will provide industry with a single contact for all the federal and state entities that work on citrus issues and better enable the collective to collaborate on policy decisions, establish priorities, allocate critical resources, and collect, analyze, and disseminate information.

The HLB MAC Group will also help coordinate Federal research with industry’s efforts to complement and fill research gaps, reduce unnecessary duplication, speed progress and more quickly provide practical tools for citrus growers to use.

HLB, also known as citrus greening, is named for the green, misshapen, and bitter-tasting fruit it causes. While this bacterial disease poses no danger to humans or animals, it has devastated millions of acres of citrus crops throughout the United States and abroad. In the United States, the entire States of Florida and Georgia are under quarantine for HLB, and portions of California, Louisiana, South Carolina and Texas are also under quarantine for the disease. The U.S. Territories of Puerto Rico and the U.S. Virgin Islands are under HLB quarantines as well.

You can find more information about HLB and the HLB MAC Group on USDA’s Multi-Agency Response toDevastating Citrus Disease website.

Patrick Cavanaugh2016-05-31T19:42:29-07:00December 13th, 2013|

COTTON GROWERS URGED TO COMPLETE PLOWDOWN

Fresno County Ag Commissioner Urges Cotton Growers To Complete Plowdown

Fresno County Agricultural Commissioner/Sealer Les Wright TODAY urged all cotton growers to complete their plowdown activities as soon as possible to maintenance a host-free period for pink bollworm. For the 2013 growing season, there were no native pink bollworm moths captured in Fresno County for 62,215 acres of cotton.

Cotton Plowdown Requirements:

Plowdown Dates for this growing season are:

December 20, 2013 – South Of Shields Avenue

December 31, 2013 – North Of Shields Avenue

Stalks must be shredded by a power-driven shredder that will effectively reduce stalks to a particle size, permitting burial and rapid decomposition.

Following shredding, tillage must be completed in such a manner that all stubs are loose from the soil around the roots and will prevent re-growth.

At this point, there are two options for cotton growers:

Conventional plowdown is done by discing all roots, plant stubs, shredded debris and trash remaining from harvesting or clean-up operations and soils around roots to the point that they are turned over and thoroughly mixed with surface soil. This method of plowdown is required in sections where pinkie has been found last growing season or this season until September 1, 2013.

Reduced tillage does NOT require the incorporation of all roots, plant stubs, shredded debris and trash remaining from harvesting or clean-up operations. If growers choose this option, they must submit a notification 10 days prior to tillage of their intention to reduce tillage on their acreage eligible for the program. Call the Department to find out which sections are not eligible for this program if you are not sure.

Once plowdown is completed by either method, any volunteer cotton must be destroyed that may appear during the host-free period, even if it is on ground that was not planted to cotton this season. If re-growth does occur during the host-free period in 2014, the grower/landowner will be cited for a violation of cotton plowdown regulations. Be sure to check fallow fields for isolated plants growing in the field and in easement areas.

Do your part to keep pinkie out of the San Joaquin Valley and finish your plowdown early to avoid the following penalties for noncompliance:

Violation Of Plowdown Date – Base fine of $500 + $5 per acre not in compliance

Repeat/Subsequent Violations – Base fine of $1,000 + $10 per acre not in compliance

In California, pink bollworm overwinters as a late stage larva in trash, at the base of cotton stalks, in soil cracks, and rarely in seeds in the unopened boll. Conventional plowdown, when done properly, kills pink bollworms in these overwintering sites. Conventional plowdown and March planting dates are designed to disrupt the life cycle of pink bollworm. It is not known whether reduced tillage practices give pink bollworm a foothold for next season. Fields using reduced tillage will be scrutinized during the host free period and next trapping season.

The late planting dates for cotton create the opportunity for “suicide emergences.” If pink bollworm emerges before the plants have begun to square, the female will lay her eggs on sheltered parts of the plant, but the larvae will die. Cotton planted too early or re-growth cotton will provide feeding and egg laying sites for pinkie.

Questions concerning proper plowdown procedure may be directed to any district office locations listed below:

Fresno 600-7510 8:00 a.m.-5:00 p.m.

Firebaugh 600-7322 1:00 p.m.-2:00 p.m.

Huron 600-7325 1:00 p.m.-2:00 p.m.

Kerman 600-7326 1:00 p.m.-2:00 p.m.

Reedley 600-7329 1:00 p.m.-2:00 p.m.

Sanger 600-7331 1:00 p.m.-2:00 p.m.

Selma 600-7327 1:00 p.m.-2:00 p.m.

The Fresno County Agricultural Commissioner’s offices will be closed on December 25, 2013 and January 1, 2014.

Patrick Cavanaugh2021-05-12T11:06:02-07:00December 11th, 2013|

Strawberry Meeting Focused on Fumigants, Pest Control

Fumigation Was Big Topic at Santa Maria Strawberry Meeting

New laws and regulations on fumigation for Santa Barbara and San Luis Obispo County strawberry growers were in place for the first time this season, and growers did a good job for the most part. This and other topics were discussed at the Wednesday’s annual Strawberry Production and Pest Management Meeting in Santa Maria.

According to Lottie Martin, Ag Biologist, Santa Barbara County Ag Commissioners office, for the most part, grower chose the right tarps for the right situation. “Growers must be careful to use a 60 percent tarp when capping a fumigation with the

Surendra Dara, crop advisor, UC Cooperative Extension, San Luis Obispo

1,3 D,” said Martin. “Growers should plan well in advance to make sure the tarp that is needed, is available.”

Martin said mandated buffer zones were noted and documented, however operators need to do a better job with required signage.

Surendra Dara, a Strawberry and Vegetable Crops Advisor, UC Cooperative Extension, San Luis Obispo, spoke about re-evaluating lygus bug IPM tools in strawberries with a focus on field vacs, monitory and economic thresholds. He spoke of an experiment with softer chemistry such as well as using B. bassiana, a soil fungus that acts as a parasite to lygus. “A combination of B. bassiana and azadirachtin.

Hillary Thomas, research manager, California Strawberry Commission

Hillary Thomas, Research Manager with California Strawberry Commission in Watsonville also spoke about lygus. Her focus was third year bug vac research for lygus control.

Kirk Larson, pomologist and strawberry production specialist with the UC South Coast Research and Education Center, Irvine

Kirk Larson, Pomologist and Strawberry Production Specialist with the UC South coast Research and Education Center, Irvine spoke about advanced selections and non-chilling plug plants.

Mark Bolda, Strawberry and Caneberry Farm Advisor and County Director with UC Cooperative Extension, Santa Cruz County spoke about strawberry transplanting and the critical importance of chilling hours necessary for strawberry production.

Steve Fennimore, Cooperative Extension Specialist, UC Davis updated attendees on the use of steam to kill soil pathogens, in place of fumigants. He said work is focused on reducing the cost and outlined possible use of a prototype machine around certain higher risk areas near buffer zones on production fields.

Karen Klonsky UC Cooperative Extension specialist

Karen Klonsky, Cooperative Extension Specialist, UC Davis spokes about the economic considerations of alternatives to fumigation and producing a second year crop.

Also speaking was Thomas Flewell, Flewell Consulting, Watsonville-Salinas. His topic focused on evaluating pest management strategies with numbers. What do the numbers mean and how do we really know what we’re doing.

A more detailed report can be found in future issue of Vegetables West Magazine. Free subscription at VegetablesWest.com.

Patrick Cavanaugh2021-05-12T11:06:02-07:00November 22nd, 2013|

AGRICULTURAL AWARDS – 2013 World Food Prize

2013 World Food Prize Winners

Three distinguished scientists — Marc Van Montagu of Belgium, and Americans, Mary-Dell Chilton, Founder and Distinguished Science Fellow, Syngenta Biotechnology, Inc.; and Robert T. Fraley, Executive Vice President and Chief Technology Officer, Monsanto—share the 2013 World Food Prize for their independent, individual breakthrough achievements in founding, developing, and applying modern agricultural biotechnology.

Their research, which makes it possible for farmers to grow crops with improved yields, resistance to insects and disease, and the ability to tolerate extreme variations in climate, can play a critical role as we face the global challenges of the 21st century of producing more food, in a sustainable way, while confronting an increasingly volatile climate. The pioneering work of these three contributed to the emergence of a new term, “agricultural biotechnology.”

With particular ties to California, Dr. Robert T. Fraley, conducted post-doctoral research in biophysics at the University of California-San Francisco. Fraley led the successful introduction of genetically engineered soybeans that were resistant to the herbicide glyphosate, commercially known as Roundup. When planting these “Roundup Ready” crops, a farmer was able to spray an entire field with glyphosate—and only the weeds would be eliminated, leaving the crop plants alive and thriving.

The World Food Prize is the foremost international award recognizing— without regard to race, religion, nationality, or political beliefs—the achievements of individuals who have advanced human development by improving the quality, quantity or availability of food in the world.

The Prize recognizes contributions in any field involved in the world food supply — food and agriculture science and technology, manufacturing, marketing, nutrition, economics, poverty alleviation, political leadership and the social sciences.

The World Food Prize emphasizes the importance of a nutritious and sustainable food supply for all people. By honoring those who have worked successfully toward this goal, The Prize calls attention to what has been done to improve global food security and to what can be accomplished in the future.

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Agriculturalist of the Year,

Fresno County

The Fresno County Farm Bureau announced that The Greater Fresno Area Chamber of Commerce and Baker, Peterson & Franklin, CPA announced that Supervisor Phil Larson was selected as the 2013 Agriculturalist of the Year, an award given annually to individuals who exemplify leadership and integrity in the Central Valley’s agricultural business community.

Supervisor Larson, a lifelong farmer and Fresno County resident, has had a long and distinguished career with the Wilbur Ellis Company and retired in 2000. His list of community involvement is extensive and includes: President, Fresno County Farm Bureau; Charter member, California Agriculture Production Consultants; California Farm Bureau District 7 State Director; and Fresno City/County Chamber of Commerce.

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Baker, Peterson & Franklin Ag Business Award

The Greater Fresno Area Chamber of Commerce and Baker, Peterson & Franklin, CPA also announced Gar Tootelian, Inc., of Reedley was awarded the 2013 Baker, Peterson & Franklin Ag Business Award, an award to a for-profit service or product-related agribusiness or farming entity headquartered in the Central San Joaquin Valley whose achievements and impact have significantly contributed to the industry and the local community.

Established in 1949, Gar Tootelian, Inc. still prospers as one of California’s oldest and largest independent agricultural chemical and fertilizer retailers. Second generation and family owned, it serves over 1,400 growers from Madera to Kern County.

Gar Tootelian provides advanced, environmentally safe, bio-technology and crop services available. Crop Life magazine recognized Gar Tootelian as the largest, single location, ag retailer in the nation, and they were named in the 10 Best Companies to work for in the Central Valley by a Business Journal survey.

At the Ag Awards Luncheon on Wednesday, November 13 at Radisson Conference Center in Fresno, the Baker, Peterson & Franklin Ag Business Award and the Fresno Chamber Agriculturist of the Year Award will be presented.

Luncheon tickets are available through the Fresno Chamber of Commerce, www.fresnochamber.com, (559) 495-4800.

Source: Fresno County Farm Bureau, CA Avocado Society

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Award of Honor, California

Avocado Commission

At its 98th annual meeting, the California Avocado Society (CAS) presented the 2013 “Award of Honor” to California Avocado Commission (CAC) Vice President of Marketing Jan DeLyser,CAS President.

“Jan DeLyser has specifically focused on the California avocado industry for the past 15 years. Her entry into the California avocado industry came at a difficult time, when foreign imports cast an ominous shadow over our livelihoods,” said CAS President Chris Ambuul. “In just 15 years, US consumption has increased five-fold, and we are still in business. Jan hasn’t just left a mark on our industry; she is a big reason why we are all still here.”

Ambuul noted that the CAS award recognizes outstanding contribution and dedication to the California avocado industry.

The California Avocado Society came into being on May 15, 1915 to promote efficiency of production and orderly marketing toward assuring long term profitability for the business of avocado growing.

Patrick Cavanaugh2021-05-12T11:03:07-07:00October 18th, 2013|

UPDATED MITE SAMPLING FOR AVOCADO ORCHARDS

Center for Invasive Species Researches the Mighty Mite

[dropcap size=big]E[/dropcap]very 60 days, California gains a new and potentially damaging invasive species. (UC Riverside)

This rate of invasion, on average, results in six new species establishing in California each year. Economic loses to California from invasive species are estimated at $3 billion per year.

The unique climate and geography of California provides diverse ecosytems that are perfect for the establishment of a diverse variety of new pests. UC Riverside’s Center for Invasive Species Research (CISR) researchers lead the way to determine how pests enter California, where invading populations came from and why these pests are successful in establishing California as their home.

Ricky Lara

Ricky Lara, a UC Riverside graduate student researcher with Mark Hoddle, Ph.D., Biological Control Specialist and Principal Investigator, is focusing on updating and reinforcing the integrated pest control program against the non-native persea mite that infests Southern California avocado orchards.

“High persea mite populations cause premature leaf drop and defoliation. Defoliation leads to sunburned bark and fruit, aborted or dropped fruit, and severely stressed trees, which ultimately reduces yields,” said Lara.

My first objective,” began Lara, “is to further develop a presence/absence sampling plan for growers so they can make keep track of pest densities throughout the growing season to guide spray application decisions. This sampling method will prevent misuse of pesticides and for PCAs to be able to provide growers with better information.”

“Because counting mites on avocado leaves is so difficult, we use a presence/absence method, or binomial sampling, by choosing 30 random leaves per tree, on orchard trees located where the mites prefer.” The sampling simply requires the numbers of avocado leaves infested with the persea mite and the numbers of clean leaves with no persea mites. This ratio of infested leaves to clean leaves is used to estimate the average number of persea mites per avocado leaf. Thus, binomial (presence vs. absence) sampling is fast and simple, and allows large areas of orchards to be surveyed quickly.

Persea Mite (UC Riverside)

“Next, I will figure out where the persea mite comes from and find and examine its natural enemies,” explained Lara. “The logic is that if a pest is not native to the area, its natural predators aren’t here either.”

Lara remarked, “Furthermore, I plan on assessing the risk that novel pesticides being developed for persea mite control pose to beneficial predatory mite populations that attack persea mite. By reducing pesticide use and conserving the presence of predators, we expect to enhance the avocado orchard ecosystem’s capacity for self-regulation of persea mite by making better use of natural enemies for pest control.”

The persea mite infests 99% of avocado acreage in California (There are no records of this pest in the San Joaquin Valley but it has been reported from avocados growing in San Francisco.) This mite is sensitive to high temperatures (>95oF) and low humidity when experienced over several consecutive days, and abrupt population crashes in the field have been observed under these conditions. The persea mite most likely originated from Mexico and arrived in California on smuggled plants.

Scientists at UCR have investigated the efficacy of releases of predatory mites for persea mite control. A highly effective natural enemy, Neoseiulus californicus,is commercially available and has been shown to be very effective, but is cost prohibitive. Seven commercial cultivars of avocado have been screened for resistance to persea mite feeding, and a new cultivar, Lamb Hass, is quite resistant to this pest.

Several species of predators occur naturally in California avocado orchards, and they have been observed to feed on persea mites. Yet, none of these natural enemies provides effective control of the mite. Nonetheless, their presence in orchards is desirable because they probably lessen the severity of persea mite infestations and will feed on other pest species.

Work is currently in progress monitoring persea mite populations, assessing predator quality after an imported shipment arrives, and refining release methodology, rates and timings of these predators.

Patrick Cavanaugh2021-05-12T11:03:07-07:00October 9th, 2013|

TODAY’S MEETING IN FRESNO ADDRESSES ACP

Fresno County on Alert for ACP

Assemblyman Jim Patterson

Assemblyman Jim Patterson hosted the Citrus Industry Town Hall this morning at the Fresno County Farm Bureau office to discuss the current state of the Asian Citrus Psyllid presence in California, the quarantine situation, how Fresno County is preparing for the possible migration of ACP into the county, and how agencies, growers, and the state and federal governments are cooperating to control its spread in California.

Over forty people attended the meeting, including growers, PCAs, local government and industry leaders, researchers, and media.

Fresno County is the fourth largest citrus-producing county in California, having dropped in status due to freeze-damaged mandarin acreage last year, according to Les Wright, Fresno County Ag Commissioner.

Les Wright

“ACP spread is one of the most serious problems facing valley citrus growers especially those in the south valley,” said Wright.

To date, all contiguous counties in southern California are under CDFA Quarantine, as well the Porterville area of Tulare County, to prevent movement of ACP-ridden leaves and plant debris and unsanitary ag equipment into non-infested regions of the state and to bide time for agency mobilization and industry research to catch up. The effort also aims to prevent ACP from finding HLB-infected trees and spreading the incurable disease.

Though presently under quarantine, the effort in southern California to stop the spread of ACP, it was emphasized, was NOT a failure; rather, it bought precious time for other regions to prepare, and while many treatments did not work, other regions are learning from their attempts.

Creative Solutions

Dr. Beth Grafton-Cardwell

Dr. Beth Grafton-Cardwell, UC IPM Specialist and Research Entomologist, recently studied ACP found in Texas and Florida and reported that local agencies here are following Florida’s lead in organizing grower groups and local neighbors to treat their trees simultaneously.

She said that researchers are looking for natural processes, among others, to control ACP populations.

Victoria Hornbaker, CDFA, Program Coordinator, gave the example of Dr. Mark Hoddle, Extension Specialist and Director of the Center for Invasive Species Research at UC Riverside, who is working towards the massive release of Tamarixia radiata wasps, a natural predator of ACP, found in Pakistan. In studies of small releases of T. radiata, the wasps were found outside the areas where they were released—a good indication of their hardiness and potential effectiveness against ACP.

Victoria Hornbaker

While there is no cure for HLB thus far, researchers are looking at altering the ACP so it cannot pick up HLB disease, inserting a gene so it cannot carry HLB, and creating disease-resistant plants.

Organic insecticides against ACP are short-lived, so they must be applied more frequently than their conventional counterparts. Thus, organic farmers must be more aggressive in their treatments.

UC Davis is studying new efficacious organic products.

If an organic farm were in an eradication zone, the grower would be required to use conventional products, losing organic status for one year. Without compliance, the property would be abated.

It is recommended that when a grower sprays for a different pest, they should choose a product that also works on ACP.

Eradication and management strategies differ according to season.

Product spraying frequency and product choice are delicate decisions so as not to cause resistance in ACP.

Expert dog sniffers can detect the presence of ACP, and have detected infested shipments that were subsequently destroyed. California is vigilant at all points of entry including airports, border traffic, and ports. Not all counties have expert canines; however, Fresno has one such specialist. The USDA also provides dogs, one of which works in Fresno.

Take Action Now

Start sampling now.

Do not rely on (color-saturated) yellow-sticky traps for detection. Remember that psyllids are attracted to citrus trees, which have both color and scent.

ACP likes an orchard’s edges, so test for their presence around a field’s perimeter, as well as down the center for good measure.

Go to the following websites for information, quarantine maps, crop protection cost-effectiveness:

· CaliforniaCitrusThreat.org

· CDFAWebsite

· UCCooperative Extension Fresno County Citrus Bug Blog

In the event a homeowner or grower suspects ACP on their property, take the bug, if possible, put it in alcohol, and contact the Fresno County Farm Bureau; Sylvie Robillard, Fresno County Grower Liaison; the CDFA Hotline, 1-800-481-1899 or your local Ag commissioner (if outside Fresno County).

Joel Nelson

Joel Nelson, California Citrus Mutual, President, commented, “If it weren’t serious, it would be exciting” due to the talent of the people involved in the fight to suppress the ACP and thereby avoid HLB disaster in the state. With southern California producing $750,000 and the Central Valley producing $1.5 billion in citrus, California is the largest citrus-producing state in the country, providing 85% of the country’s fresh citrus.

Stopping the spread of ACP and eradicating Huanglongbing (HLB) is among the top five priorities of the USDA. The federal government has contributed $10 million to the California program toward that end.

A coalition of groups is conducting a public relations campaign starting in southern California that includes distribution of bookmarks and brochures (in several languages) that have a little magnifying glass inside to detect ACP; enlisting legislators and box stores, among others, to help spread information; and launching a PSA next week featuring Citrus Grower Kevin Severns speaking about this crucial situation.There are 6 versions of the PSA on CCM’s YouTube Channel.

Nelson emphasized that every step this coalition in California takes is globally unprecedented. And the government is flexible and ready to adopt new strategies; using this effort in California as a model for other programs planned to eradicate foreign invading pests.

Assemblyman Jim Patterson concluded by acknowledging, “Agriculture is more than a livelihood; it‘s a life.”

Patrick Cavanaugh2021-05-12T11:06:03-07:00August 24th, 2013|

Blue Prune Drop

Blue Prune Drop and Leaf Scorch in Glenn and Tehama Counties

According to Bill Krueger UC farm advisor emeritus, Glenn County and Richard Buchner UC farm advisor, Tehama County, overheated prunes are succumbing to pressure due to high temperatures over the last few weeks. Blue prune drop and, in some cases, an associated leaf scorch, often develops following the rapid onset of high temperatures as occurred in June of this year.

Damaged prunes color prematurely (turn blue) and usually drop from the tree. The sun-exposed fruits on the top or south side of the tree are more likely to be affected by becoming sunken or flattened. Leaf scorch and dieback may develop in leaves and twigs near the damaged fruit. When damaged leaves dry, the veins may be a darker brown than the rest of the leaf.

Blue prune drop is associated with heat stress. Excessive heat results in damage to the fruit that is thought to produce a toxin which is transported to spurs, leaves and shoots resulting in the leaf scorch symptoms. Leaf scorch symptoms are always associated with damaged prunes. They do not occur in areas of the tree with no fruit or on young trees without a crop. Anything affecting fruit temperature can have an effect. This would include:

1. Irrigation – Drop and particularly scorch are generally more severe on shallow soils with limited water holding capacity or in orchards toward the end of their irrigation cycle at the onset of heat. Adequate soil moisture insures maximum evapotranspiration and cooling of the plant.

2. Tree Position or Fruit Location – Leaf scorch is usually worse on overheated border trees, or on the south side of individual trees with greater sun exposure.

3. Cultural Practices – Blue prune appears to be less severe in orchards with cover crops than in clean tilled or drip irrigated orchards. Transpiration from an adequately irrigated cover crop should contribute to orchard cooling. In addition, a vegetated orchard floor reflects less sunlight than dead vegetation or bare ground.

4. Nutrition – While blue prune and leaf scorch does not appear to be directly related to potassium deficiency, anything adversely affecting tree health and condition could contribute to higher fruit temperatures. Adequate tree nitrogen levels promote vegetative growth that shades fruit from direct sunlight.

Krueger and Buchner report they have no sure ways of preventing blue prune drop and the associated leaf scorch. However, you can reduce the risk by making sure trees are healthy, vigorous and well supplied with water. Because the damage is caused by heat and not a disease, it should not continue to expand in the tree. Damaged wood should be pruned out during the dormant season.

Source: University of California Division of Agriculture and Natural Resources Cooperative Extension

Patrick Cavanaugh2016-05-31T19:47:14-07:00July 4th, 2013|

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