The U.S. Department of Agriculture has released three new citrus rootstocks that are available for unrestricted public use. The rootstocks are US SuperSour 1, US SuperSour 2 and US SuperSour 3. A new publication provides summary information about the new releases. Get the new publication here: Sponsored Content5 Facts About Fire Ants and How to Control ThemApril 30, 2024BRAZILIAN RESEARCH …
Rootstock/Scion Combos: What Works and What Doesn’t
By Ernie Neff For Phil Rucks and Tom Powers at Phillip Rucks Citrus Nursery in Frostproof, Florida, selecting rootstock and scion combinations starts by acknowledging that some varieties just don’t do well with HLB. “We don’t recommend some varieties regardless of rootstock,” Rucks says. Powers says varieties that are especially difficult to grow with HLB are Hamlin, midsweet and pineapple …
Rootstock Choice May Be Key in Tree Productivity
Florida citrus growers recognize the Sugar Belle® mandarin hybrid for its tolerance of citrus greening disease, and new findings from the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) suggest that rootstock selection may play a role in keeping Sugar Belle® trees productive even if they become infected with the bacterial malady. “We now have proof of concept …
Field Testing of New HLB-Tolerant Scions and Rootstocks
By Rhuanito S. Ferrarezi, Jude W. Grosser, Fred G. Gmitter, Ed Stover and Kim Bowman Citrus is Florida’s most important agricultural commodity. The state produces citrus for different markets: round oranges for juice; navels, mandarins, grapefruit and lemons for the fresh-fruit industry; and lemons for extracting peel oil for processing. Huanglongbing (HLB) disease affects all citrus varieties. Since the discovery …
Alternatives to Rootstock Propagation by Seed: Differences, Concerns and Expectations
By Ute Albrecht Commercial citrus rootstock propagation traditionally occurs via use of nucellar apomictic seed, which generates genetically identical seedlings that are used as liners for budding. With the high demand for superior rootstocks in the age of HLB, commercial nurseries are currently experiencing a shortage of seeds for some of the most popular rootstock varieties. In addition, for many …
Some Rootstocks Succumbed to Irma
Researchers inspecting their groves at the Southwest Florida Research and Education Center after Hurricane Irma found that trees on certain rootstocks were very likely to be uprooted. Fernando Alferez, a horticulturist at the Immokalee center, discusses the uprooted trees and hopes he has for fresh citrus growing. “This is anecdotal evidence from our experience here,” Alferez says. “What we saw …
Rootstocks and HLB Tolerance — Another Perspective
By Ute Albrecht Tolerance to a disease is generally defined as the ability to be productive in the presence of disease-causing organisms. This is contrary to resistance, which is defined as the ability to completely evade a pathogen due to specific resistance mechanisms. The question as to what defines an HLB-“tolerant” rootstock was posed in an article by Bill Castle, …
Time to Get Serious About Trialing New Scion/Rootstock Combinations
By Jude W. Grosser and Frederick G. Gmitter It’s no secret that citrus greening disease, or HLB, continues to take a heavy toll on the beloved Florida citrus industry. It has been estimated that the industry will need to replant over 3 million trees per year for the next 10 years just to get back to normal. So the million-dollar …
Field Trials of Rootstocks and Scions: What Can They Tell Us?
By Harold Browning Column sponsored by the Citrus Research and Development Foundation Plant breeding programs have been a mainstay of citrus production worldwide. They have served as a basis for gradual improvement in fruit quality, adaptability to varying growing environments, and most importantly, to disease management. For that reason, new germplasm has been a front line of pursuit in the …
HLB and ‘Tolerance’ as a Practical Matter in Choosing Rootstocks
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 …
Improved Rootstock Selection Tool
Florida Citrus Rootstock Selection Guide: New Custom Query Option The third edition of the Florida Citrus Rootstock Selection Guide was recently released online at flrootstockselectionguide.org and has now been expanded to include an expert system to aid growers in rootstock selection. The expert system was developed as a collaborative effort of Steve Rogers, Bill Castle, Steve Futch and Andrew Persaud. …
Study Looks at Interaction Between OTC and Soil Microbiome
A wealth of observations are being recorded by growers and scientists on the effects of trunk injection of oxytetracycline (OTC). Visually, trees have responded with better canopies. Hopefully, higher yields and quality will continue to follow the applications. But what about below ground? There have been recorded improvements in citrus root mass in treated trees. Sarah Strauss, associate professor of …
Irrigation and Fertilization Advice for Georgia Citrus
Jake Price, University of Georgia (UGA) county Extension coordinator, recently wrote the following article about irrigation and fertility for Georgia citrus: I don’t think it has rained since my last blog! Make sure to check your irrigation to make sure it’s working properly. In the research plot, it is very common for the microjets to be stopped up or not spraying properly. …
ACP Management in High-Density Plantings
By Jawwad Qureshi The Asian citrus psyllid (ACP, Figure 1) is the vector of huanglongbing (HLB) disease associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus. Infected trees start to decline and produce poor-quality fruit, which drops prematurely. Consequently, citrus production has decreased dramatically since the advent of HLB in Florida in 2005. There is no cure for the disease yet. …
Seeking a Partner for OTC
Few would dispute that the approval of oxytetracycline (OTC) for use as a trunk-injection therapy to treat HLB is one of the biggest breakthroughs in the nearly two decades of fighting the disease. Most Florida citrus growers believe the therapy has been a net positive and they are committed to continuing the treatment. However, there’s a stipulation in the labels …
Millennium Block Research Shows Promising Results
A recent update of Millennium Block research at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Indian River Research and Education Center in Fort Pierce indicates the 5,500 trees in the project are yielding promising results. The four trials within the Millennium Block aim to unlock the genetic potential of new scion and rootstock hybrids never tested …
Some Grapefruit Showing Less HLB Symptoms
A recent update of the U.S. Department of Agriculture Multi-Agency Coordination (MAC) Project evaluating multiple grapefruit varieties on different rootstocks reveals that some combinations have less HLB symptoms than others. Jackson has one of the lowest ranks for disease index across the combinations. The healthiest trees in the trial include: At least half of the blocks in the MAC trial …
Interstock Pros and Cons for HLB Management
The pros of using interstocks for HLB management seemed to outweigh the cons, based on a presentation horticulturist Manjul Dutt made at this spring’s Florida Citrus Growers’ Institute. Dutt is a University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) assistant professor. An interstock is a graft of a citrus selection that can be used as a bridge between …
Supporting Citrus Science
By Rob Gilbert, ragilber@ufl.edu, @IFAS_VP Let’s start with the most important thing. Citrus science remains a top priority of the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS). Citrus is special. My goal for citrus is sustainability. That means profitability. Here are a few new ways UF/IFAS has demonstrated its support for citrus science during the past five …
Have Questions About Trunk Injection? Ask the Expert for Answers
Sponsored Content In this special series, Tom Johnson, owner of TJ BioTech, tackles questions about optimizing trunk-injection applications to treat HLB. Q: Are there any advantages or disadvantages to making a ReMedium TI® Injection in the rootstock or the scion? Tom Johnson: To start, agronomically there is really no difference in a ReMedium TI® injection into the rootstock or the …