Mary Sutton, University of Georgia (UGA) assistant professor and citrus Extension specialist, recently wrote about the causes of alternate bearing in Georgia groves. Alternate bearing is a common problem in many mandarin varieties. A slightly edited version of Sutton’s report follows. CARBOHYDRATES During photosynthesis, leaves produce sugars that are either exported and utilized for growth or stored as starch in …
PGRs Can Produce Remarkable Results
Tripti Vashisth, associate professor of horticultural sciences with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), has been studying the use of plant growth regulators (PGRs) to improve citrus tree health and fruit retention for several years now. Her work has culminated into a systems approach of when to use a particular PGR at a certain time …
All In For Citrus Podcast, April 2025
April is a busy month for citrus events. The Florida Citrus Growers’ Institute was held in Avon Park early in the month followed by a citrus field day at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Southwest Florida Research and Education Center (SFWREC) in Immokalee. These events are the topic of the April episode of the …
Fundecitrus Researchers Participate in International Citrus Conference
Researchers with Brazil’s Fundecitrus discussed HLB-related topics at the recent 15th International Citrus Conference in South Korea. Fundecitrus’ Franklin Behlau participated in the section of papers related to HLB, also known as citrus greening disease. Most of the papers provided updates on the disease situation in different locations, including Florida, China, India, Nepal, Indonesia, Iran and Brazil. Behlau discussed the …
What Past Hurricanes Reveal About Recovery
After hurricanes hit citrus-producing regions in Florida, there is always one question included in the conversation: How bad is it? Experience has shown that the damage from hurricanes can take months to fully manifest. And recovery can take years, especially in the HLB-era. Within a week after Hurricane Milton making landfall on Oct. 9, the University of Florida Institute of …
Reduce Post-Hurricane Fruit Drop With PGRs
By Tripti Vashisth and Taylor Livingston Hurricane Milton passed over many citrus-producing counties in Florida, resulting in canopy and fruit loss (especially in early varieties). HLB-affected trees undergo a lot of stress, and now the hurricane has added more abiotic stress to trees. High-speed winds caused significant fruit and leaf drop. The fruit and leaves that escaped the drop during the …
How to Help Trees Recover From High Winds
By Christopher Vincent Hurricane Helene’s path spared most of the citrus industry the kind of trouble that Hurricane Ian brought back in 2022, but Ian taught us some important lessons you can use if your trees were hit by high winds. WIND SPEED MATTERS Trees impacted by Category 3 winds were mostly defoliated, with major limbs broken and near 100% …
The Best Defense for Mitigating Preharvest Fruit Drop
By Tripti Vashisth Over the past decade, HLB-associated fruit drop has become a significant problem in Florida groves. Many growers opt to harvest the fruit before the peak fruit drop begins. However, the downside to this strategy is that the fruit does not get enough time for optimal Brix accumulation. Plant growth regulators, when applied at the right time, can …
PGRs Promote Tree Health
The use of plant growth regulators (PGRs) has been a popular method to treat HLB-infected citrus trees. The materials have continued to be applied in conjunction with trunk injection of oxytetracycline (OTC) to improve tree health. Tripti Vashisth, an associate professor of horticultural sciences with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), has been studying PGRs …
All In For Citrus Podcast, June 2024
The educational seminars at the June Florida Citrus Industry Annual Conference covered a wide range of topics intended to give growers hope that progress is being made in the fight against HLB. During the June All In For Citrus podcast, Michael Rogers, director of the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center, …
Integrating Antibiotics Into a Broader Management Plan for HLB
By Lukasz Stelinski, Eric Roldan and Kirsten Pelz-Stelinski Use of antibiotics in fruit production is not a new idea, but it has only recently been applied on a larger scale in Florida citrus. The initial labels for huanglongbing (HLB) treatment with antibiotics in Florida citrus were approved in March 2016 in response to significant economic losses caused by HLB. Antibiotics …
Podcast Addresses Recent Irrigation Research
It was a dry April in most of Florida’s citrus-production areas. That means irrigation is vital to keep HLB-infected trees adequately watered. The drier months of the year from February through May are when flowering and fruit set are occurring. If trees are stressed due to water deficit during this time, they are more likely to suffer fruit drop and …
PGRs for HLB-Affected Trees: An Update
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 …
PGRs: Multipurpose Tools for Citrus Improvement
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 …
Taking Available Tools to the Grove
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 & …
Bud Advisories Help Growers Time Psyllid Sprays
The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) is reminding citrus growers that flower bud advisories are now being issued. The UF/IFAS advisories can help growers determine when to spray for HLB-spreading Asian citrus psyllids and when to stop spraying in an effort to protect pollinating bees. Tripti Vashisth, a UF/IFAS associate professor of horticultural sciences, will …
HLB Treatments ‘A Mixed Bag of Results’
A variety of treatments Florida citrus growers are using for HLB have so far produced mixed results, according to observations reported by Highlands County Citrus Growers Association (HCCGA) President Aaron Nelson. In a recent association newsletter, Nelson wrote that many are anxious to see harvest data showing what effects the treatments have had over the past year. The treatments he …
All In With Trunk Injection
Some Florida citrus growers decided to start slowly with trunk injection of oxytetracycline (OTC), treating only a small portion of their acreage. Others took a wait-and-see approach, hoping to learn from their peers’ experiences. But Wheeler Farms went all in, treating 100% of their trees with trunk injection. “What we were doing was not working, so we needed to try …
$5 Million Awarded to UF/IFAS for HLB Research
The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) has been awarded five federal grants totaling more than $5 million to control HLB. The grants are from the U.S. Department of Agriculture’s National Institute of Food and Agriculture (NIFA). HLB is caused by the bacterium Candidatus Liberibacter asiaticus (CLas). The Asian citrus psyllid can transmit CLas into a …
Combine Plant Growth Regulators for Most Benefit
Using the plant growth regulators (PGRs) gibberellic acid (GA), 2,4-D and cytokinin in combination can maximize the benefit for HLB-affected trees, researcher Tripti Vashisth reported recently. The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) associate professor of citrus horticulture and production works at the Citrus Research and Education Center in Lake Alfred. She discussed the benefits of …