Nutrition, Family and Consumer Sciences
University of California
Nutrition, Family and Consumer Sciences

Posts Tagged: Asian citrus psyllid

Planting alternative backyard fruit trees in Southern California can help stop citrus threat

Southern California's mild Mediterranean climate makes it ideal for growing fruit trees in backyards, community gardens and school gardens. The trees provide wholesome fruit along with shade, beauty and enrichment for families and communities.

UCCE sustainable food systems advisor Rachel Surls.
“With fresh fruit close at hand, it's easier to follow dietary guidelines that encourage filling half our plates with fruits and vegetables for good health,” said Rachel Surls, UC Cooperative Extension sustainable food systems advisor. “Besides, gardening is a great activity. Tending fruit trees teaches natural science, responsibility and appreciation for fresh food. And a garden gets people outside and engaged in physical activity.”

Citrus trees are favorites for Southern California backyards, but Surls and her team aim to get local gardeners thinking beyond lemons, limes, oranges and other citrus fruit. In the past several years, a deadly plant disease has been spreading among Southern California citrus, prompting quarantines and putting citrus orchards across the state at risk.

Surls and her team are working on an initiative with a corps of volunteer UC Master Gardeners in Los Angeles and surrounding counties to promote selection and planting of appropriate fruit trees. New brochures, a website, workshops and one-on-one consultations will guide Southern Californians in making tree decisions that are scientifically sound and community-focused.

The project addresses serious concerns about the rapid spread of huanglongbing (HLB) disease, also known as citrus greening. The insect that spreads HLB – the Asian citrus psyllid – was introduced into California in 2008. The disease made its first California appearance in a Los Angeles County backyard in 2012. HLB, which eventually kills every tree it infects, is now spreading rapidly in urban areas of Los Angeles and Orange counties, where quarantines have been put in place by the California Department of Food and Agriculture (CDFA).

“Citrus trees are so popular in Southern California. They are part of our history and regional identity,” Surls said. “Now we have the unfortunate responsibility of telling residents about this serious problem we are facing. In some cases, residents who live near infected trees should be proactive and remove their lemon, orange, mandarin and lime trees and replace them with different kinds of fruit.”

Find out how close HLB is to your home - https://ucanr.edu/sites/AltsToCitrus-ACP-HLB/
New web app shows residents' proximity to HLB disease

University of California Agriculture and Natural Resources IGIS programmers, in collaboration with UC Cooperative Extension, have created an HLB Monitoring Web App that allows residents to enter an address to determine how close they are to confirmed HLB outbreaks. If they are within 2 miles of a residence where an HLB-infected citrus tree was found, the app recommends replacement of citrus trees with non-citrus fruit trees, such as apples, peaches, avocados or persimmons.  

Residents with citrus trees that are 2 to 5 miles from areas with HLB should keep a close eye on their trees, treat for Asian citrus psyllid and begin thinking about planting an alternative to citrus if the disease spreads to their area.

“Huanglongbing poses a serious threat to both backyard and commercial citrus in California if its spread is not halted,” Surls said. “By removing trees in areas where HLB has been found, residents are helping reduce its ability to spread, buying time for scientists to find a cure.”

CDFA is testing trees throughout the state and removing HLB-infected trees. However, the first visible symptoms of HLB – yellow mottled leaves – can appear months to years after infection. Even if they look perfectly healthy, citrus trees can be harboring the disease and allowing it to be spread by the tiny psyllid insect. 

Current hotspots shown on the HLB Monitoring Web App include Rosemead, Montebello, Pico Rivera, San Gabriel, Hacienda Heights and Cerritos in Los Angeles County. In Orange County, HLB is spreading in communities around Garden Grove, Westminster and Santa Ana.

“We know removing citrus trees is going to be really hard for people,” Surls said. “But if you live within two miles of an infected tree, your tree is probably already infected, and HLB means your tree is going to die.” 

To ease the transition, UC Master Gardeners are informing residents about alternatives that will produce fruit that's nutritious and delicious.

“So many types of fruit trees can be grown in Southern California,” Surls said. “Honestly, we have almost unlimited options. We live in a fruit tree grower's paradise. So we want to encourage local residents to think seriously about selecting non-citrus trees to replace their citrus.”

The information can also inform residents who are planning a new backyard orchard. 

“They should consider some of the many wonderful fruit trees we can grow here — plant a pomegranate, plant a peach, plant a persimmon — but resist the temptation to plant more lemons, oranges and other citrus trees,” Surls said.

Making the decision to plant a certain type of tree should not be taken lightly.

“Planting a fruit tree is a big commitment. It will be part of your garden for years. Research the best options for your family and locations,” Surls said. “The UC Master Gardeners are here to help.”

Following are good options to consider for replacing citrus trees in Southern California, although recommendations may vary based on local climate:

Apples
Certain apple varieties that do not need to be exposed to cold temperatures grow and produce well in Southern California. Low-chill varieties include Anna, Beverly Hills, Dorset Golden, Fuji and Gala. 

Figs
Figs grow well in full sun in Southern California. They can reach 10 to 30 feet tall, and are best for spacious areas.

Jujube
Jujubes are less common in Southern California, but are a valued fruit in Southeast Asian and will grow well under Southern California conditions. They grow about 15 feet tall. Jujubes are a good selection for inland valleys that get hot during the summer. The fruit tastes like small, crispy apples. Dried, they are similar to dates.

Loquat
A small- to medium-size tree that grows 10 to 20 feet high, loquats are easy to grow and have relatively few pests. Fresh, ripe loquats are sweet and aromatic. They can be used in jams, sauces and garnishes.

Persimmon
Persimmons ripen in autumn after the leaves have fallen, creating a beautiful landscape display. They are easy to grow in full sun and part shade. Persimmons can be eaten fresh or dried for a date-like fruit.

Pomegranate
Well-suited to Southern California's Mediterranean climate, pomegranates grow to about 15 feet in height. Pomegranates are pest- and disease-resistant. The fruit's seeds, coated with astringent juicy flesh, are called arils. Use arils to top salads or other dishes, or squeeze for juice or to make jelly.

Other fruit tree options for Southern California include mangos, guavas, pineapple guavas, peaches, nectarines and pears.

For more research-based information about alternative fruit trees, visit the UC Agriculture and Natural Resources website “California Backyard Orchard” at http://homeorchard.ucanr.edu.

Contact your local UC Master Gardener Program for additional advice:

Los Angeles County – http://celosangeles.ucanr.edu/UC_Master_Gardener_Program   

Orange County – http://mgorange.ucanr.edu

Riverside County – https://ucanr.edu/sites/RiversideMG

San Bernardino County – http://mgsb.ucanr.edu

Ventura County – https://ucanr.edu/sites/VCMG 

Jean Suan harvests persimmons, fruit that is easy to grow and creates a beautiful landscape display.

Funding for the ‘Alternatives to Citrus Fruit in the Fight against Huanglongbing Disease' project was made possible by the U.S. Department of Agriculture's (USDA) Agricultural Marketing Service through grant AM180100XXXXG003. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the USDA.

Posted on Monday, September 9, 2019 at 10:24 AM
Focus Area Tags: Food Yard & Garden

Citrus industry, UC Riverside and UCCE team up to fight a citrus killer

Leaves on a Florida tree show symptoms of HLB disease. The new biosafety lab at UC Riverside will help scientists battle the disease. (Photo: Beth Grafton-Cardwell)
Researchers at the University of California, Riverside, will soon have a new resource to help them fight a disease devastating the citrus industry.

On June 6, citrus industry, university and government leaders gathered at UC Riverside Citrus Variety Collection to announce a joint effort to fight huanglongbing (HLB), also known as citrus greening disease. Huanglongbing is a bacterial plant disease fatal to citrus trees

The effort will result in construction of a biosafety-level 3 plant facility in Riverside, about two miles north of UC Riverside.

The biosafety-level 3 plant facility will allow researchers, including many from UC Riverside who are experts on citrus pests, diseases and breeding, to conduct work with plant pathogens that previously couldn't be done in Southern California. (There is only one other such facility in California – at UC Davis.)

The new biosafety-level 3 building will be built and owned by the California Citrus Research Foundation, which is funded by citrus growers.

At the June 6 gathering, Kim Wilcox, chancellor of the UC Riverside, spoke about the establishment in 1907 of the Citrus Experiment Station in Riverside. That research station eventually grew into UC Riverside. He noted that the research station received a boost after a 1913 freeze that devastated the citrus industry.

“Now, unfortunately, 100 years later, we have a different kind of natural threat, Wilcox said. “It's not weather in this case but an insect. And again the university, the federal government and private partners have come together and said ‘We can address this.'”

Georgios Vidalakis and Mark Hoddle are two UC Cooperative Extension specialists based at UC Riverside who will benefit from the facility.

Vidalakis is a UCCE specialist in plant pathology and director of the Citrus Clonal Protection Program at UC Riverside. The program provides a safe mechanism for the introduction into California of citrus varieties from around the world.

“Having access to live plants that carry the bacteria is very, very important to our program because it allows us to develop and validate diagnostic techniques much more quickly,” Vidalakis said.

Vidalkis has ongoing projects at the biosafety-level 3 plant facility in Davis as well as one in Maryland. Having his experimental material hundreds or thousands of miles away is a difficult, costly and inefficient way to conduct science, he said.

“This new facility in Riverside will help tremendously in the fight against HLB,” he said. “It is also a great investment for future threats to the California citrus industry.”

Hoddle is a UCCE specialist in entomology and director of Center for Invasive Species Research at UC Riverside. In recent years, Hoddle has released two species of wasps native to Pakistan that are natural enemies of the Asian citrus psyllid, the vector of a bacterium that causes HLB.

Hoddle called the biosafety facility a critical resource for righting HLB that will greatly assist UC Riverside researchers.

“This investment will likely allow more rapid and cost effect progress in developing mitigation strategies and novel technologies for managing HLB in California's iconic citrus crop,” Hoddle said.

Posted on Monday, June 13, 2016 at 9:47 AM

Industry citrus day planned at UC Riverside

A selection of citrus varieties available for tasting at a past citrus day.
The University of California, Riverside, will host the 5th annual citrus field day for citrus growers and citrus industry professionals on Jan. 27 at the university's agricultural operations fields.

Among the topics is Asian citrus psyllid (ACP), which is off particular concern to citrus growers at the moment. The exotic pests can spread huanglongbing (HLB) disease, an incurable condition that has already seriously impacted the citrus industries in Florida and Texas. A few trees in urban Southern California backyards have been found infected with HLB and were pulled out and destroyed.

At the citrus field day, UC Agriculture and Natural Resources Cooperative Extension specialist Matt Daugherty will discuss the potential for nurseries to contribute to Asian citrus psyllid and huanglongbing spread. Regulations are in place in California that restrict movement of containerized citrus and require specific insecticide treatments. Daughterty is evaluating how well such steps reduce the risk of human-mediated Asian citrus psyllid spread. He is using a combination of monitoring in nurseries, field experiments on chemical control efficacy, and characterization of the effects of nursery practices on psyllid management.

Another speaker, UC ANR Cooperative Extension specialist Philippe Rolshausen, will explain how bacteria, fungi and viruses associated with plants, either on its surface or inside, can affect plant health and productivity. He will demonstrate how these organisms can be used for disease control using Pierce's disease of grapevines as an example and also drawing a comparison with huanglongbing in citrus.

The event, with a mix of presentations and field tours, is scheduled from 8 a.m. to 3 p.m. Advance registration, which is $25, is required. The deadline is Jan. 22. There will be no day-of-event registration available.

To register visit: https://form.jotform.com/53556635957975. For more information call (951) 827-5906.

The following is a tentative agenda:

  • 8 a.m. – Introductions by Peggy Mauk, director of agricultural operations at UC Riverside and a subtropical horticulture extension specialist, and Tracy Kahn, curator of UC Riverside's Citrus Variety Collection.

  • 8:10 a.m. – Welcomes from Kathryn Uhrich, dean of UC Riverside's College of Natural and Agricultural Sciences and Michael Anderson, a divisional dean for agriculture and natural resources

  • 8:30 a.m. – Minimizing the potential for nurseries to contribute to Asian citrus psyllid spread in California – Matt Daugherty, UC ANR Cooperative Extension specialist, entomology. 
  • 9:15 a.m. – Microbiota-based approach to citrus tree health – Philippe Rolshausen, UC ANR Cooperative Extension specialist, subtropical horticulture. 

  • 9:45 a.m. – Low seeded citrus – variation in seed content and its causes – Mikeal Roose, professor, botany and plant sciences at UC Riverside. Roose specializes in plant breeding, particularly with citrus.

  • 10:30 a.m. – Break

  • 11 a.m. – Novel detection methods for Huanglongbing – Wenbo Ma, associate professor, plant pathology at UC Riverside .Her research is focused on developing methods that detect Huanglongbing by monitoring so-called “effectors” secreted from the bacterial pathogens causing the disease.

  • 12 p.m. – Lunch (catered by Anchos Southwest Grill).

  • 1 p.m. – Pesticide safety training – Vince Samons, UC Riverside agricultural operations.

  • 1:45 p.m. – Walk-through of the Citrus Variety Collection, rootstock trial and phytophthora root rot trial.

To make a tax-deductible contribution to the Citrus Variety Collection Endowment fund or the Citrus Research Center & Agricultural Experiment Station support fund go to the following link and select College of Natural and Agricultural Sciences then select the specific fund: https://advancementservices.ucr.edu/GivingForm.aspx

Posted on Tuesday, January 19, 2016 at 4:39 PM
 
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