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UF/IFAS Citrus Research

UF/IFAS Citrus Research

HLB Management 


UF/IFAS HLB Research Outcomes: A Promise Delivered
UF/IFAS researchers have found more solutions for managing Huanglongbing (HLB or citrus greening) in the last 15 years than in the last 100 years before it was found in Florida.
With this science -based information, Florida citrus producers have a fighting chance to continue to be the nation’s largest producer of orange juice and a world leader in citrus research and development.
There are more than 100 ongoing HLB research projects in UF/IFAS that fall under one of the general areas of focus listed below.

Insect (psyllid) and Pathogen Control the Give Trees a Fighting Chance

  • New psyllid control programs are being developed that reduce pesticide use in favor of more environmentally friendly, sustainable solutions for pest management
  • Field testing on numerous anti-bacterial products and plant-derived compounds are being conducted that eliminate the HLB – causing bacteria in the plant or reverse the plant damage to restore tree growth and productivity.

Breeding New Greening-Tolerant Trees

  • Citrus growers are now planting new HLB-tolerant citrus varieties released by UF/IFAS that will live linger and produce better-quality fruit.
    • Watch a video  about the UF/IFAS Citrus  breeding program click here

Integrated Grove Management Solutions

  • Research has shown that growers can improve root performance through proper soil pH management for maximum nutrient uptake by the root system 2 ½ years after soil acidification, yields in HLB-infected groves improved significantly.
  • Research on growing citrus under protective screen (CUPS) has led to hundreds of acres of specialty fresh fruit varieties being planted and grown, revitalizing the Florida gift-fruit shipping segment of the citrus industry. Protective covers for new trees is another innovation.

Rootstock/Scion Selection 

UF/IFAS breeders have screened thousands of rootstock hybrids for HLB tolerance that could be transmitted to grafted scions. They have identified a few truly promising selections.  The combination of UF OLL-8 cultivar on UFR-4 rootstock has a strong performance for both yield and tree health.

For a list of  HLB tolerant varieties that have been developed by UF/IFAS breeders, Click Here.

When preparing for replanting, an important factor to consider is the choice of rootstock. Choosing the right rootstock and scion combination can result in higher economic returns without any additional cost. Rootstocks affect scion vigor, yield, fruit size, juice quality, and pest tolerance. However, tree growth, yield, and fruit quality interact strongly with climate, soil type, tree spacing, and other factors, often producing contradictory reports on rootstock performance in different areas.

Rootstock selection should be based on soil adaptability, soil pH, pest and disease pressure, desired tree spacing and size control, and other characteristics. Several new rootstock selections were recently released, but not much information exists on their long-term performance under different environmental conditions and different commercial management. Many of these new rootstocks are currently being evaluated under the Fast Track program and it is anticipated that new information will be available soon. Also important is the choice of scion to be used in combination with the selected rootstock. Several novel scion varieties have been released by the breeding programs at the USDA and the University of Florida. These novel varieties are expected to have better field performance (disease tolerance) and better fruit quality, making some of them suitable for the fresh fruit market.

2019–2020 Florida Citrus Production Guide: Rootstock and Scion Selection

Ute Albrecht, Fernando Alferez, and Mongi Zekri  Download here