Pests and Diseases

Detection of Huanglongbing Triggers Quarantine in Ventura County; First HLB Detection in County

Courtesy of Citrus Insider

The California Department of Food and Agriculture (CDFA) has declared a quarantine in Ventura County following the detection of the citrus disease Huanglongbing (HLB), or citrus greening, in two citrus trees on one residential property in the city of Santa Paula. These detections are the first HLB-positive trees in Ventura County. CDFA is working with the United States Department of Agriculture and the Ventura County Agricultural Commissioner on this cooperative project.

The disease was detected in plant material taken from one orange and one lime tree in a residential neighborhood in the Santa Paula area of Ventura County. These detections follow the confirmation of a Candidatus Liberibacter asiaticus (CLas)-positive Asian citrus psyllid (ACP) sample taken from the find site.

CDFA crews will be working to remove and dispose of the infected trees and are conducting a mandatory survey of every property within 250 meters of the detection site. After the survey is complete, all host plants in the 250-meter area around the detection site will be treated to suppress the disease vector, the ACP. By taking these steps, a critical reservoir of the disease and its vectors will be removed, which is essential to protect the surrounding citrus from this deadly disease.

These detections establish a mandatory five-mile citrus HLB quarantine area around the find site. The quarantine area is bordered on the north by Ojai Road; on the south by E Los Angeles Avenue; on the west by Wells Road; and on the east by Balcom Canyon Road. The quarantine prohibits the sale of all host nursery stock and the movement of all host plants or plant parts within a five-mile radius of the finds. The quarantine applies to residents and commercial operations alike. These detections will also place parts of Ventura County into Bulk Citrus Regional Quarantine Zone 6, which will require any commercial citrus growers to apply an additional mitigation step(s) to move fruit within or from this zone. Production and retail nurseries within the five-mile quarantine are being contacted by CDFA and will be issued a hold notice preventing the sale of nursery stock host plants. Visit CDFA’s Map and Quarantines page for more details.

Growers in Ventura County should contact Grower Liaisons Sandra Zwaal at szwaal2@gmail.com or Cressida Silvers at cressidasb@gmail.com for additional information about these detections. In response to the HLB detections in Santa Paula, a grower meeting is being held on Wednesday, Oct. 4. Stay tuned to Citrus Insider for details or reach out to the Grower Liaisons for more information.

An HLB quarantine area currently exists in parts of Los Angeles, Orange, Riverside, San Bernardino and San Diego counties, where more than 6,300 residential trees have tested positive for the disease and have been removed.

To read the full press release, please visit the CDFA website.

2023-10-04T08:09:53-07:00October 4th, 2023|

Asian Citrus Psyllid Study: Vigilance Urged but ‘No Cause for Panic’

By Mike Hsu, UCANR

Preliminary results indicate 3.5% of ACP collected showed signs of bacterium that can cause huanglongbing

An ongoing study in the commercial citrus groves of coastal Southern California is looking at whether Asian citrus psyllids – the insect vector of huanglongbing “citrus greening” disease – are carrying the bacterium that can cause HLB.

Thus far, the project has tested more than 3,000 adult ACP collected from 15 commercial citrus sites across the region, of which 138 – just over 3.5% – had some level of the bacterium present, according to researchers from UC Agriculture and Natural Resources, UC Davis, UC Riverside and the University of Arizona, Tucson.

“While the results are a cause for concern, the situation in California is much better than in Florida and Texas, where ACP carrying the bacterium make up the majority of the population and HLB is widespread in commercial citrus,” said Neil McRoberts, a UC Davis plant pathologist and UC Integrated Pest Management program affiliate advisor. “The results indicate that there is no room for complacency, but also no cause for panic.”

Since the first HLB-infected tree in California was found in 2012, nearly 4,000 infected trees have been detected and removed from residential properties in Southern California, mainly in Orange and Los Angeles counties. According to McRoberts, “to date, no HLB has been found in commercial citrus” in California.

He stressed, however, that the aforementioned ACP study – funded by the HLB Multi Agency Coordination Group and managed by USDA-APHIS – does not involve any testing of trees for HLB and focuses only on looking at the insect which spreads the bacterium.

McRoberts also emphasized that the project’s detections of the bacterium cannot be considered “official” because the researchers’ lab procedures differ from the official testing protocols of the California Department of Food and Agriculture.

“Follow-up sampling by CDFA staff would allow official samples to be collected for further investigation, but is entirely voluntary for the growers involved,” he said, adding that his research team is currently wrapping up the sampling phase of the project, with data analysis continuing into 2023.

While commending the “huge coordinated effort” by the California citrus industry, California Department of Food and Agriculture, UC ANR and other partners to suppress the ACP vector and slow the spread of HLB, McRoberts also urged continued vigilance.

“Our study results indicate that it is not time to declare the emergency status for ACP/HLB in California over – the situation is still evolving,” he said.

2022-11-21T11:20:37-08:00November 21st, 2022|

Western Growers Premieres Video Series Featuring Next-Generation Agtech Robots

By Ann Donahue, Western Growers

From two-dimensional orchards to flying autonomous robots to lasers killing weeds, today’s agriculture combines the best of science and science fiction.

To celebrate the start of the first American edition of FIRA, the international agricultural robotics conference, WG debuts an inside look at cutting-edge technologies on the farm that will help ease the industry’s ongoing labor shortage.

The three short videos feature 2-D orchards of trees harvested via a self-propelled platform; flying autonomous robots working alongside harvest crews; and AI-directed blades and lasers that zap weeds with ruthless efficiency.

The videos are available in their entirety now on the Western Growers YouTube channel, and will be rolled out on WG social platforms. Click here for a playlist of all the videos; links for individual videos and their embed codes are available below.

Future of Tree Fruit Harvesting

Drone Harvest

Robotic Weeding

2022-10-18T09:41:17-07:00October 18th, 2022|

Confirmation of New Citrus Virus in California

By Citrus Insider

The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) has confirmed positive identifications of Citrus yellow vein clearing virus (CYVCV) in the city of Tulare detected during California Department of Food and Agriculture’s (CDFA) routine multi-pest survey. This is the first detection of CYVCV in the United States. CDFA is surveying for the disease in Tulare County residential and commercial properties and will survey in Fresno and Kings counties in the coming months to fully determine the extent of the disease’s presence (which is currently limited to the city of Tulare). The survey results will inform the regulatory approach taken by CDFA and APHIS.

CDFA began initial delimitation survey work in March in a 1-mile core radius area around the initial find site. Since then, CDFA has conducted additional surveys in the surrounding areas, which have resulted in additional CYVCV confirmations in the city of Tulare, expanding the survey area. CDFA is conducting these surveys to gain knowledge on the extent of the infestation and potential impacts of CYVCV, and surveys will be ongoing for the near future. Since the detection of this virus is new to the United States, these learnings – CDFA’s robust pest prevention system that focuses on exclusion and monitoring, as well as CDFA and USDA’s experience responding to other vectored disease threats – will be critical in developing an appropriate regulatory response.

CYVCV can be spread by vectors as they move from tree to tree feeding on foliage. The vectors include citrus whitefly, green citrus aphid, melon or cotton aphid, and cowpea aphid, which are all known to be present in California. CYVCV can also be spread through grafting and the movement of infected propagative materials and rootstocks, or contaminated tools and equipment. While there is no treatment for CYVCV, as of now the best mitigation measure is to control the vector and sanitize tools and equipment. To the greatest extent possible, growers are encouraged to urge their field crews to clean and sanitize all their equipment thoroughly in between jobs or when moving between groves.

For any questions about CYVCV, please call the CDFA Pest Hotline at 1-800-491-1899 or contact your local Grower Liaison.