Build Resilience in HLB-Affected Hamlin Trees

Josh McGill HLB Management, Tip of the Week

By Taylor Livingston and Tripti Vashisth Fighting HLB alongside weather disasters like freezes and hurricanes is leaving growers with little options for sustaining yields. The Hamlin sweet orange variety is known for higher susceptibility to HLB symptoms which cause rapid tree decline, including increased pre-harvest fruit drop and canopy loss. Production strategies that target fruit drop and canopy health improvement …

Gibberellic Acid Shows Promising Results on Hamlin

Josh McGill HLB Management, PGRs, Research

By Tripti Vashisth and Taylor Livingston Grower-led trials in 2022 showed positive results of gibberellic acid (GA) treatment on Hamlin trees in Florida. This article primarily discusses two growers’ trials in detail. Both sites showed improvement in fruit production from the GA application. Many growers have adopted GA applications in the past year as part of their grove management strategy. …

Examining Hamlin Survivor Trees

Josh McGill HLB Management, Research, Varieties

By Gary England, Fred Gmitter and Manjul Dutt In 2014, most groves in Central Florida had citrus greening infection rates approaching 100%, but a Lake County grower reported that some trees in his Hamlin on Swingle blocks seemed to be relatively healthy. Some visual HLB symptoms were observed on these “surviving” trees, but they did not have the massive fall …

Gibberellic Acid Application on Hamlin Appears Promising

Josh McGill Research

By Tripti Vashisth In a multi-year field trial, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers have seen beneficial effects of gibberellic acid (GA) on Valencia sweet oranges. Monthly application of GA (September to January) on Valencia improved yield on average by 30%, reduced fruit drop and elicited enhanced plant defense response. These benefits are possibly due …

Parson Brown Outperforming Hamlin

Ernie Neff Research, Varieties

Manjul Dutt recently discussed his research on the Parson Brown (PB) sweet orange, which shows some characteristics that could make it more attractive than Hamlin, Florida’s leading early-season orange. Dutt is a University of Florida Institute of Food and Agricultural Sciences horticultural sciences researcher at the Citrus Research and Education Center in Lake Alfred. Dutt’s research, funded by the Citrus …

Trials to Seek Hamlin Alternative

Ernie Neff Varieties

Twenty-four citrus scions were approved by the Citrus Research and Development Foundation (CRDF) on March 23 for eventual use in multiple field trials around Florida. The purpose of the trials will be to find an early-season orange that is more tolerant of HLB disease than Hamlin, said CRDF Chief Operating Officer Rick Dantzler. Hamlin has long been the primary early-season …

Rootstock Effects on Valencia and Hamlin in Large-Scale Commercial Plantings

Tacy Callies Research, Rootstocks

By Ute Albrecht, Sudip Kunwar and Jude Grosser Prior to 1865, the only rootstocks used in Florida were sour orange and sweet orange. Use of grafted trees instead of seedling trees became necessary because of the devastating effects of phytophthora on sweet orange. Sour orange was widely used as a rootstock because of its resistance to phytophthora and other positive …

Varieties: Replacing Hamlins with Early Valencias

Ernie Neff Varieties

University of Florida/Institute of Food and Agricultural Sciences plant breeder Jude Grosser makes a case for Florida’s citrus industry replacing Hamlin oranges with early-maturing Valencia oranges that he and others are developing. “I think that’s a no-brainer because Hamlins are having a really bad time with greening, and orange juice sales are declining,” Grosser says. “Hamlin is half our juice. …


Grower Panel: OTC a Net Positive So Far

Daniel Cooper Events, HLB Management

Florida Citrus Mutual recently hosted a roundtable discussion about the performance of trunk-injection therapies as growers are making their second round of applications. The grower participants included Jim Snively, Southern Gardens Citrus; Glenn Beck, Beck Bros. Citrus and Wes Soria, Sorrells Citrus. University of Florida scientist Ute Albrecht also joined the panel to provide a research update. Rick Dantzler, chief …


Final Orange Forecast for Brazil’s 2023–24 Season

Daniel Cooper Brazil, Crop Forecast

Fundecitrus and its cooperators published the final orange production forecast on April 10 for the 2023–24 crop season in Brazil’s São Paulo and West-Southwest Minas Gerais citrus belt. The forecast calls for 307.22 million 90-pound boxes of oranges, unchanged from the February forecast. The final forecast by variety is: The season’s production was 2.2% lower than the prior year’s crop …


CRAFT Program Promotes New Planting and Knowledge

Daniel Cooper CRAFT, planting, Research

Since its founding in 2019, the Citrus Research and Field Trial (CRAFT) program has been responsible for the planting of just under 10,000 acres of new trees. This includes about 6,000 acres of solid-set groves and just shy of 4,000 acres of resets. CRAFT is a first-of-its-kind program and considered an innovation among funding agencies needed to support such efforts. …


Surviving to Fight Another Day

Daniel Cooper Florida, HLB Management

Bill Lennon is working with researchers to learn more about survivor trees that are standing up to HLB. Bill Lennon is a fifth-generation citrus grower who can recall the industry’s glory days when Central Florida had hundreds of thousands of citrus acres before the 1980s freezes pushed production southward in the state. But he’s remained dedicated to the area, managing …


CRISPR Is Bringing Citrus Closer to HLB Resistance

Daniel Cooper Breeding, HLB Management, Research

You’ve probably heard the term CRISPR in recent years. It is a relatively new breakthrough in science that has applications in human health and even in the fight against HLB. Nian Wang, a professor of microbiology and cell science with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), has been on the forefront of CRISPR research. Here …


CITRUS NURSERY SOURCE: A Day of Learning About New Rootstocks and Varieties

Daniel Cooper Citrus Nursery Source, Rootstocks, Varieties

By Peter Chaires The U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) U.S. Horticultural Research Laboratory and Florida Citrus Research Foundation (FCRF) jointly held an open house, variety display and field tour at the W.H. Whitmore Foundation Farm between Leesburg and Groveland in early December. This annual event provides a great opportunity for industry members to see the latest innovations in …

HLB-affected trees

PGRs for HLB-Affected Trees: An Update

Daniel Cooper HLB Management, PGRs

Using the plant growth regulators (PGRs) cytokinin in spring, gibberellic acid (GA) in summer and 2,4-D in late fall can be helpful for HLB-affected trees, horticulturist Tripti Vashisth reported. Her PGR update came during a Feb. 21 OJ Break. Multi-county citrus Extension agent Chris Oswalt hosted the event at the University of Florida Institute of Food and Agricultural Sciences Citrus …

Brazil Citrus Season Nears End

Daniel Cooper Brazil, Crop Forecast

The Feb. 9 forecast for the 2023–24 orange crop in the São Paulo and West-Southwest of Minas Gerais citrus belt of Brazil is unchanged from December 2023 at 307.22 million boxes of 40.8 kilograms each. This represents a reduction of 0.7% when compared to the initial forecast for the season. Of the total estimated production, approximately 27.76 million boxes are …


PGRs: Multipurpose Tools for Citrus Improvement

Daniel Cooper PGRs, Tip of the Week

By Tripti Vashisth Canopy health of HLB-affected citrus has been directly related to disease severity, fruit drop and overall fruit production. Some success has been found with the use of certain plant growth regulators (PGRs) such as gibberellic acid (GA) and 2,4-dichlorophenoxyacetic acid (2,4-D) to achieve healthier trees with reduced fruit drop and increased production. HLB MANAGEMENT Application of these …

Crop Transformation Center

Crop Transformation Center Takes Aim at HLB Resistance

Daniel Cooper Breeding, HLB Management, Research

By Frank Giles The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) has established itself as a leader in new technological frontiers like artificial intelligence (AI). In fact, the school has the 15th most powerful computer in the world. The HiPerGator, as the computer is called, will assist in AI development and on many other technological fronts. Another …

Taking Available Tools to the Grove

Tacy Callies HLB Management

The quest for long-term solutions to HLB is well underway. Technology like CRISPR is being developed to introduce tolerance or resistance to HLB. Conventional breeding also is seeking rootstocks and varieties that can resist the disease. In the meantime, growers are reminded to utilize available tools that help trees remain productive in an HLB environment. During the August Citrus & …

Studying the Mechanisms for HLB Tolerance

Tacy Callies All In For Citrus Podcast, Research, Varieties

John Chater has been on the job now for two years, working with growers to evaluate variety performance in field trials. In the latest All In For Citrus podcast episode, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) assistant professor discusses his work, including grower collaboration to study new varieties in real-world environments. Chater also talks about …