Impact of HLB on Fruit Growth and Retention

Jim Rogers Fruit Drop, HLB Management

By Tripti Vashisth and Mary Sutton Citrus trees affected by huanglongbing (HLB) consistently have small fruit and low fruit numbers at harvest. The low fruit numbers are largely attributed to the increased rates of preharvest fruit drop that accompany HLB. Small fruit is more likely to drop during this preharvest period, suggesting a link between fruit size and retention. To …

What’s Next for the Donaldson Citrus Variety?

Jim Rogers HLB Management, Research

During this summer’s Florida Citrus Industry Annual Conference, Matthew Mattia, a post-doctoral associate with the U.S. Department of Agriculture (USDA), discussed his work to identify the origins of the Donaldson citrus variety. The variety is a single tree on the USDA A.H. Whitmore Foundation Farm near Groveland, Florida. Mattia was the first to discover the tree on the farm in …

Protect Against Psyllids in Early Shoot Development

Jim Rogers Brazil, HLB Management, Research

A Fundecitrus study found that the first four stages of orange tree shoot development are the ones that should be most protected against HLB-spreading psyllids. The Brazilian association reported that among the six stages of shoot development, the first four (V1 to V4) are the most attractive to the psyllid and favorable for its feeding and reproduction. Therefore, those are …

Advantages and History of Trunk Injection

Jim Rogers HLB Management, Pesticides

Plant physiologist Ute Albrecht recently gave a presentation on increased fruit yield and other apparent benefits of injecting the antibiotic oxytetracycline into citrus tree trunks. The University of Florida Institute of Food and Agricultural Sciences researcher also discussed other advantages that trunk injection provides. These advantages include: Precise delivery of materials Elimination of spray drift Reduced risk for worker exposure …

Non-Certified Donaldson Trees: Limited Availability for Growers

Jim Rogers Florida Department of Citrus, HLB Management

The Florida Department of Citrus’ Program for Expedited Propagation (PEP) of HLB-tolerant and resistant trees was conceived during the 2022 Florida legislative session following the discovery of the Donaldson tree among the collection at Whitmore Farms. The goal is to provide the resources needed to ramp up availability of Donaldson trees and others like it, so that growers interested in …

Two New Tools in the Fight Against HLB Seek EPA Registration

Jim Rogers HLB Management

The recent Florida Citrus Industry Annual Conference featured educational presentations on navigating production in an environment where HLB is endemic in groves. Two of those presentations focused on new technology being developed for use in citrus. Two companies, Elemental Enzymes and TJ BioTech, have been collaborating with the Citrus Research and Development Foundation (CRDF) to research their respective products’ potential …

Brazil

Microregion Maps in Brazil Help With HLB

Jim Rogers Brazil, HLB Management, Research

Microregion maps developed by Fundecitrus should help Brazilian citrus growers make the necessary decisions to combat HLB disease, also known as greening. Fundecitrus explained that the incidence of HLB differs in the various regions of Brazil’s extensive citrus belt. To allow citrus growers to better understand the places where the disease is located, a study by Fundecitrus divided the belt …

It’s Almost Time to Spray Gibberellic Acid

Jim Rogers HLB Management, Tip of the Week

By Tripti Vashisth Gibberellic acid (GA) can benefit citrus trees in many ways. GA can improve vegetative and fruit growth while reducing fruit drop and flowering intensity. Evidence is mounting that repeated application of GA is needed to induce the desired positive effect on fruit growth and tree productivity. In a multiyear field trial on Valencia orange, monthly application of …

Expedited Tree Propagation Program Approved

Jim Rogers Florida Department of Citrus, HLB Management, nurseries

The Florida Citrus Commission (FCC) on July 20 approved the Florida Department of Citrus’ (FDOC) plan for implementation of the Program for Expedited Propagation of HLB Tolerant and Resistant Trees (PEP). The program’s goal is to provide resources needed to ramp up the availability of the apparently HLB-tolerant Donaldson tree and others like it. The FDOC received $1 million in …

Trunk Injection for HLB: Pros and Con

Jim Rogers HLB Management, Pesticides, Research

The pros of injecting the antibiotic oxytetracycline (OTC) into citrus tree trunks to combat HLB appear to be numerous, including increased fruit yield, according to scientist Ute Albrecht. On the other hand, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researcher only discussed one con, but it was a big one. “Trunk injections cause injury, and long-term …

HLB Cause and Control Explained

Jim Rogers HLB Management, Research

University of Florida Institute of Food and Agricultural Sciences researcher Nian Wang reported in a July 20 webinar that HLB is a pathogen-triggered immune disease. After explaining the sequence in which the disease attacks trees, he suggested ways growers can use that knowledge to combat HLB. Wang is a microbiologist and cell scientist at the Citrus Research and Education Center. …

Progress in Developing Improved Citrus Rootstocks to Mitigate HLB

Jim Rogers HLB Management, Research, Rootstocks

By Jude Grosser, Manjul Dutt and Fred Gmitter Exploiting citrus genetic diversity is the key to defeating HLB. Plant species have survived for millennia with evolving, hostile pathogens. This is possible through natural selection within genetically diverse populations. Tolerant or resistant individuals survive and intermate, get through the bottleneck, and the species evolves. Current citriculture is based on extremely limited …

HLB-Tolerant Tree Program Progressing

Tacy Callies Florida Citrus Commission, Florida Department of Citrus, HLB Management

The goal of an expedited tree propagation program is to have several million HLB-tolerant or HLB-resistant trees planted in the next several years. Greg Hodges, assistant director of the Florida Department of Agriculture’s Division of Plant Industry (DPI), said he believes that goal is attainable. Hodges and others presented the propagation plans to the Florida Citrus Commission (FCC) on July …

California HLB Quarantine Areas Expanded

Jim Rogers California Corner, HLB Management, Regulation

Federal and state officials in late June expanded the areas quarantined for huanglongbing (HLB, also known as citrus greening), caused by Candidatus Liberibacter asiaticus, in California. The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) took the action in cooperation with the California Department of Food and Agriculture (CDFA). APHIS added portions of Los Angeles, Orange, Riverside …

Alternative Management Tools for ACP Under Development

Jim Rogers Education, HLB Management, Psyllids

By Lourdes C. Pérez Cordero Management of the Asian citrus psyllid (ACP) in the HLB era is incredibly important. This well-known insect can vector and facilitate the spread of the bacterium associated with HLB disease. Therefore, effective reduction of ACP populations can be beneficial for the citrus industry. But how exactly do we manage this pest? Unfortunately, there is not …

Reduce HLB Pressure and Enhance Growth With Kaolin

Jim Rogers HLB Management, Tip of the Week

By Christopher Vincent Kaolin particle film is a non-toxic tool to reduce psyllids and increase tree growth. Particle films are nothing more than a suspension of solid particles that make a “film” on the leaves after they dry. They work mostly by reflecting light. Kaolin is the most common type of particle film because the clay is mined directly and …

California Panel Issues HLB Update

Jim Rogers California Corner, HLB Management, Pests

California’s commercial citrus groves remain free of HLB disease 14 years after Asian citrus psyllids (ACP) were first detected there. The state’s Citrus Pest and Disease Prevention Program (CPDPP) described that as “no small feat” in its recently released 2020-21 annual report. “The past fiscal year presented its fair share of headwinds for citrus-growing operations,” the report stated. “From pandemic-induced …

Florida Citrus Industry Conference Draws Record Crowd

Jim Rogers Awards, Events, HLB Management

Citrus growers and industry stakeholders gathered in Bonita Springs last week for the Florida Citrus Industry Annual Conference. After being sidelined the previous two years due to COVID-19, the conference drew a record crowd of more than 500 registered attendees. The event, hosted by Florida Citrus Mutual, was packed with educational programming and meetings for various industry groups. The Citrus …

ACP Detection Response: ‘The System Is Working’

Jim Rogers California Corner, HLB Management, Pests

County and state officials in California have been actively responding to various Asian citrus psyllid (ACP) discoveries in the Central Valley in recent weeks. Kern, Tulare and Fresno counties have all reported an ACP detection over the last month. The Citrus Pest and Disease Prevention Division (CPDPD) has been implementing delimitation protocols and necessary treatment programs. CPDPD Director Victoria Hornbaker …