U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) scientists are studying the possibility of the Donaldson sweet orange replacing the HLB-ravaged Hamlin in orange juice (OJ). The scientists work at the U.S. Horticultural Research Laboratory in Fort Pierce, Florida. While assessing citrus trees with oranges that might be used for commercial OJ production, the scientists found the Donaldson tree at the …
Apply Brassinosteroids to Improve Hamlin Brix
By Fernando Alferez and Divya Aryal Brassinosteroids (BRs) are a class of plant growth regulators with several effects on plant growth and development. University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) work in the last few years has shown that BR treatments may influence internal maturity in Hamlin sweet orange if performed at the right time. Research has …
Build Resilience in HLB-Affected Hamlin Trees
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
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
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
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
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
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
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
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. …
Florida Citrus Show: A Day of Education and Enjoyment
The Florida Citrus Show marked another successful event in March in Fort Pierce. The show provided attendees with a fun, informative day to learn about citrus and specialty crops while engaging with exhibitors during the tailgate-style trade show. CRAFT UPDATE Citrus Research and Field Trial (CRAFT) programs have been very popular with growers and have incentivized new citrus plantings across …
CITRUS NURSERY SOURCE: Thought About Brixy?
By Peter Chaires Nurseries and growers are continuously searching for suitable substitutes for Hamlin sweet orange to supply the early/mid-season orange juice market. Besides traditional sweet oranges, many new hybrids are in various stages of development. Some of these are likely to rise to the level of commercial viability in the orange-like category. Growers wanting to trial an orange-like hybrid …
Final Brazil Orange Forecast for 2025–26
Fundecitrus on April 10 reported the final forecast for the 2025–26 orange crop for Brazil’s São Paulo and West-Southwest Minas Gerais Citrus Belt. The forecast is for 292.94 million 90-pound boxes. Of the total, about 25.69 million boxes were produced in the Triângulo Mineiro region. Production this season was 26.9% higher than the previous crop, which reached 230.87 million boxes. …
Sneak Peek: April 2026 Citrus Industry
The Citrus Industry section of the April 2026 issue of Specialty Crop Grower highlights ongoing efforts to strengthen Florida’s citrus sector amid challenges. Articles this month showcase education, nutrient management and variety development. A recap of the Florida Citrus Show details a successful March event in Fort Pierce that combined education with a lively tailgate-style trade show. Growers Daniel Hunt, …
CITRUS NURSERY SOURCE: Important Details About Newly Available Citrus Varieties
By Peter Chaires There are presently two groups of University of Florida (UF) citrus varieties, licensed to Florida citrus nurseries via New Varieties Development & Management Corp. (NVDMC), the licensing designee of the Florida Department of Citrus. These include: GROUP ONE Get more details on group one in the February 2025 Citrus Nursery Source article. GROUP TWO Find more information …
Match the PGR to the Purpose at the Proper Time
By Tripti Vashisth and Prudhvi Vulchi Plant growth regulators (PGRs) have become an important management tool for Florida citrus growers facing the challenges of huanglongbing (HLB). HLB disrupts the tree’s hormonal balance by reducing growth-promoting hormones like cytokinin and gibberellins and increasing stress-related hormones. This imbalance weakens carbohydrate transport, reduces sink strength and accelerates canopy decline. PGRs can help restore …
New Funding for CRAFT Emerging Varieties Program
The Citrus Research and Field Trial (CRAFT) Foundation recently provided information about a new funding opportunity for growers participating in the Emerging Varieties (EV) Program. CRAFT received additional funding from the Florida Department of Citrus, which will be used to reimburse growers for some of their costs associated with the royalties for five of the varieties included in the EV …
Brazilian Orange Forecast Updated
The Feb. 10 forecast for Brazil’s São Paulo and Triângulo/Sudoeste Mineiro region is 292.6 million boxes of oranges. That’s a 0.7% reduction from the Dec. 10 forecast of 294.81 million boxes, and a 7% reduction from the initial forecast of the season on May 9 of 314.6 million boxes. The reduction is due to a decrease in the average size …
Top Florida Varieties and Rootstocks
Valencia SPB 1-14-19 remained the most propagated Florida citrus variety for at least the fourth straight year in 2024–25, according to the Florida Department of Agriculture and Consumer Services (FDACS). The FDACS Division of Plant Industry’s Bureau of Citrus Budwood Registration recently released the Citrus Budwood Annual Report 2024–25. The report is a highly detailed 44-page document. US-942 returned as …
CITRUS NURSERY SOURCE: Increased Interest in Fresh Utilization
By Peter Chaires Florida breeding programs have been largely focused on the juice stream in recent years. And for good reasons. Retaining the remaining processing capacity and infrastructure is of paramount importance to support Florida’s orange juice industry. Numerous sweet oranges have been released in hopes of achieving incremental improvements in HLB tolerance while improving juice quality. Likewise, there has …




























