HLB and ‘Tolerance’ as a Practical Matter in Choosing Rootstocks

Tacy CalliesRootstocks

By Bill Castle (Editor’s note: Click on the graphs throughout the article to enlarge them.) By classic biological definition, a particular citrus rootstock-scion combination when infected with Candidatus Liberibacter asiaticus (CLas) would be considered tolerant if infected trees had no more than slight reductions in performance, sometimes accompanied by a reduced level of the pathogen. That definition implies that the …

phytophthora

Managing Phytophthora in Cold-Hardy Citrus

Daniel CooperCold Hardy, Diseases

In Florida, the soilborne phytophthora pathogens — primarily Phytophthora nicotianae and Phytophthora palmivora — are the leading causes of root rot, crown rot and foot rot. Two University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers recently wrote about phytophthora management in cold-hardy citrus. The authors are Assistant Professor and Extension Specialist Muhammad Shahid and postdoc Carlos Aucique-Perez, …

young

Two-Step HLB Defense for Young Trees

Daniel CooperIPCs, Research

A newly published study suggests that the use of individual protective covers (IPCs) followed by monthly applications of homobrassinolide (HBr) after IPCs are removed is beneficial. The two-step approach can help young mandarin trees stay healthier longer and produce more fruit in Florida’s HLB-endemic environment. The study, “Combining Individual Protective Covers and Homobrassinolide Treatment Prolongs Tree Health and Increases Fruit …

biofertilizer

Early Data on Biofertilizer for HLB-Affected Trees

Daniel CooperNutrition

By Flavia Tabay Zambon and Paulo Eduardo Branco Paiva Florida’s citrus industry has faced severe decline due to huanglongbing (HLB, also known as citrus greening). Production has dropped 92% since the 2003–04 season, according to the U.S. Department of Agriculture Economic Research Service. Growers have relied on cultural practices, tolerant varieties and antimicrobial treatments, especially oxytetracycline (OTC), which has recently …

varieties

Take a Closer Look at New Varieties at the Citrus & Specialty Crop Expo

Morgan ColeCitrus Expo, Varieties

For the past several years, John Chater, University of Florida Institute of Food and Agricultural Sciences assistant professor of horticultural sciences, has been charged with acting as a conduit between citrus breeders and growers seeking information on new varieties and rootstocks to plant. Chater has worked with growers to evaluate new varieties planted in the real world. This has given …

new

Experience What’s New at the Citrus & Specialty Crop Expo

Daniel CooperCitrus Expo, Events

The 2026 Citrus & Specialty Crop Expo is returning Aug.12–13 to Fort Myers, bringing fresh opportunities for Florida growers to learn, connect and discover the latest innovations shaping the industry. This year’s Expo will be held at the Caloosa Sound Convention Center in downtown Fort Myers, with the Luminary Hotel just steps away. The new waterfront venue features an updated …

NVDMC

CITRUS NURSERY SOURCE: NVDMC Research Focus for 2026–27

Daniel CooperCitrus Nursery Source, Research

By Peter Chaires Spring is planning season for most Florida citrus organizations. New Varieties Development & Management Corp. (NVDMC) is no exception. The board recently met with all breeding teams to review 2025–26 sponsored projects and establish research priorities for 2026–27. Though some aspects of these projects will be covered in greater depth in future articles, this month’s column is …

Florida grapefruit

IMG and Mixon Form Florida Grapefruit Partnership

Daniel CooperFlorida, Grapefruit

IMG Citrus and Mixon Family Citrus have announced a partnership to serve Florida grapefruit customers around the world. The partnership combines Mixon’s citrus under protective screen (CUPS) production with IMG’s experience marketing grapefruit across North America, Europe and Asia. Both entities are multigenerational Florida agribusiness families. The partnership is expected to account for more than half of Florida’s fresh grapefruit …

years

Three Years of OTC Trunk Injection Provide Cumulative Benefits

Daniel CooperHLB Management, Research

By Ute Albrecht, Gabriel Pugina and Larissa Nunes According to a recent industry survey, 64% of Florida citrus growers have injected their trees for three consecutive years with oxytetracycline (OTC). This article reports the results from three research trials conducted by the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Plant Physiology Team at the Southwest Florida Research …

climate change

Climate Change Is Changing Citrus Nutrition

Daniel CooperNutrition, Weather

Climate change is creating new challenges for citrus growers, and one of the biggest impacts is on tree nutrition. According to a recent article in Frontiers in Plant Science authored by an international team of researchers, rising temperatures, changing rainfall patterns, drought, flooding, salinity and elevated carbon dioxide levels are all affecting how citrus trees take up and use nutrients. …

salt

The Search for Salt-Tolerant Citrus

Daniel CooperInternational, Rootstocks, Varieties

Scientists with Tunisian and Swedish universities recently wrote “Salinity–Chloride Interaction Effects on Novel Citrus Combinations Under Various Field Conditions,” which was published in Horticulturae. The authors are Hend Askri, Sywar Haffani, Hager Snoussi, Rim Zitouna-Chebbi, Tarek Fezzani and Asma Najar — all with Université de Carthage in Tunisia — and Ronny Berndtsson with Lund University in Sweden. A brief summary …

June 2026

Sneak Peek: June 2026 Citrus Industry

Daniel CooperAwards, Research, Sneak Peek

The Citrus Industry section of the June 2026 issue of Specialty Crop Grower focuses on leadership and research. On the cover of the magazine is Ned Hancock, winner of the 2026 Citrus Achievement Award. He is being recognized for his decades-long leadership and dedication to serving Florida’s citrus industry. Don’t miss the accompanying video in the digital issue of the …

meeting

Florida Citrus Mutual Hosts Spring Grower Meeting

Daniel CooperEvents, Florida Citrus Mutual

Florida Citrus Mutual hosted its spring informational meeting for growers at Golden Ridge Groves in Alturas on May 13. Golden Ridge Groves is growing fresh fruit in citrus under protective screen and recently added you-pick and agritourism options for the public. Steven Hall, executive director of the Citrus Research and Field Trial (CRAFT) Foundation, gave an update and recounted the …

crop expo

New Location and Format for the Citrus & Specialty Crop Expo

Daniel CooperCitrus Expo, Events

The 2026 Citrus & Specialty Crop Expo makes its return to Fort Myers on Aug. 12–13 at the waterfront Caloosa Sound Convention Center. The Luminary Hotel, the event’s host hotel, is conveniently connected to the convention center. ENJOY YOUR STAY The new venue offers several opportunities to refresh and improve the Expo. The convention center will allow educational seminars to …

CarriCea

CarriCea Rootstock Registration Is ‘a Major Milestone’

Daniel CooperHLB Management, Regulation, Rootstocks

Growers association Florida Citrus Mutual (FCM) on April 28 called the Environmental Protection Agency’s (EPA) approval of Soilcea’s CarriCea™ T1 citrus rootstock registration “a major milestone.”  According to FCM, CarriCea™ T1 is a first-of-its-kind citrus rootstock designed to tolerate citrus greening disease. It works by precisely editing the rootstock’s own genes, disrupting the bacterium that causes greening from interacting with the …

trunk

Trunk-Injection Takeaways Presented

Daniel CooperHLB Management

Researcher Ute Albrecht on April 21 shared lessons learned from three years of oxytetracycline (OTC) trunk injection for HLB management in Florida. Albrecht is an associate professor with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) specializing in citrus plant physiology. She works at the Southwest Florida Research and Education Center. Albrecht reported on results of a …

Florida

Florida Citrus Show: A Day of Education and Enjoyment

Daniel CooperEvents, Florida Citrus Show

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 …

education

Citrus & Specialty Crop Expo: Education and Connection

Daniel CooperCitrus Expo

Citrus and specialty crop growers will have a great opportunity this summer to gather, learn and connect at the Citrus & Specialty Crop Expo. The event is set for Aug. 12–13 at the Caloosa Sound Convention Center in Fort Myers. The annual Expo brings together citrus and specialty crop producers for two days focused on practical education and valuable industry …

Gmitter and Grosser

Gmitter and Grosser Receive Rare Award

Daniel CooperAwards

University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) citrus breeders and geneticists Fred Gmitter and Jude Grosser recently received the rare Citrus Research and Education Center (CREC) Resident Professorship Award. The award has only been bestowed four other times in CREC’s 109-year history. The award recognizes careers that have brought distinction to the CREC through outstanding programs, important …

mandarin

Complex Responses to IPCs in Mandarin Trees

Daniel CooperHLB Management, IPCs, Mandarins

Recent research showed that individual protective covers (IPCs) proved highly effective in reducing Asian citrus psyllid (ACP) populations and thereby preventing HLB infection in three mandarin cultivars. However, overall tree response varied. The research was published in the Journal of the American Society for Horticultural Science. The authors are Saoussen Ben-Abdallah, Susmita Gaire, Ute Albrecht, Ozgur Batuman, Jawwad Qureshi and …