Optimizing Gibberellic Acid Applications in Florida Citrus

Josh McGill Fruit Drop, HLB Management

Tripti Vashisth, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) associate professor of horticultural sciences, has dedicated several years of research into the use of plant growth regulators like gibberellic acid (GA) to fight fruit drop in citrus. In the August All In For Citrus Podcast, Michael Rogers, director of the UF/IFAS Citrus Research and Education Center, interviewed …

Combined Treatment Reduced Drop and Increased Size

Josh McGill Fruit Drop, HLB Management, Production

A combination of gibberellic acid (GA) and 2,4-D reduced preharvest fruit drop by 18% and improved fruit size but produced no statistical effect on yield, researcher Tripti Vashisth reported Aug. 30. The combination “seems promising,” the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) horticulturist stated. The report was based on first year results from a trial of …

Psyllid Management Alert for Brazil

Josh McGill Brazil, HLB Management, Psyllids

The onset of rains in several regions of Brazil’s citrus belt has made it necessary for growers to pay added attention to citrus greening, Fundecitrus reported. The association of citrus growers and juice manufacturers from the state of São Paulo said the extra attention is needed due to the increase in greening-spreading psyllid populations in this period. Fundectirus reported that …

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All In For Citrus Podcast, August 2022

Josh McGill All In For Citrus Podcast, Fruit Drop, HLB Management

The August episode of the All In For Citrus podcast takes listeners on a deep dive into the use of plant growth regulators like gibberellic acid (GA) to help fight fruit drop. The episode features an in-depth conversation between Michael Rogers, director of the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center, and …

Progress With HLB Products

Josh McGill Citrus Expo, CRDF, HLB Management

Rick Dantzler, chief operating officer of the Citrus Research and Development Foundation (CRDF), spoke during the general session of the Citrus & Specialty Crop Expo. He provided an update on products he hopes will help the citrus industry reset and begin to increase production again. The products are two oxytetracycline (OTC) materials that can be injected into citrus trees. “We …

Citrus Industry Weighs In on Oxytetracycline Trunk Injection

Josh McGill HLB Management, Pesticides

Trunk injection of oxytetracycline (OTC) has been proposed as a means to manage HLB in citrus. University of Florida research shows OTC injections increase yield and fruit quality but cause tree injury. TJ BioTech expects to receive EPA registration in late fall of this year for an OTC product that could be injected into trees. Florida citrus industry growers and …

A Two-Pronged Approach to Suppress Psyllids

Josh McGill HLB Management, Psyllids, Research

By Bryony C. Bonning and Lukasz L. Stelinski Asian citrus psyllids (ACP) transfer the pathogen that causes citrus greening from plant to plant as they feed. After confirmation of citrus greening in Florida in 2005, growers intensified their use of insecticides against ACP to try to stop disease spread. However, this method alone has yielded variable success and increased costs. …

Impact of HLB on Fruit Growth and Retention

Josh McGill 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?

Josh McGill 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

Josh McGill 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

Josh McGill 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

Josh McGill 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

Josh McGill 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 …

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Microregion Maps in Brazil Help With HLB

Josh McGill 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

Josh McGill 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

Josh McGill 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

Josh McGill 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

Josh McGill 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

Josh McGill 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 …