By Larry Duncan Citrus trees in Florida soils infested with diaprepes root weevil (Diaprepes abbreviatus) or sting nematode (Belonolaimus longicaudatus) frequently contend with devastating damage to their root systems. This is made even worse by root loss due to huanglongbing (HLB) disease. Where soil conditions are conducive to the insect or nematode, it is very difficult to prevent major economic …
Lessons on Yield and Root Health From Modified Nutrition
By Davie Kadyampakeni, Evan Johnson, Kelly Morgan and Ali Atta Citrus production in Florida has been decreasing over the last 15 years due to several factors, with huanglongbing (HLB) a major driver. This disease has severe effects on citrus growth and production, including stunted vegetative growth, misshapen small fruits and poor color development, root mortality, stunted branches, excessive fruit drop, …
Field Trials for Cultivar Evaluation; Soil and Root Health
University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) citrus researchers are collaborating on ground-breaking research projects to fight against HLB. They are working with researchers at the University of California-Riverside (UC-Riverside), Texas A&M and Washington State University on a project to field-test new citrus cultivars for tolerance or resistance to HLB. The research is funded by the U.S. …
Improving Root Health in the Era of HLB
Developing and maintaining a healthy root system is crucial for establishment and long-term productivity of citrus trees. The presence of HLB can greatly complicate citrus root-health management. The infection causes severe damage to fibrous roots that amplify the detrimental effects caused by other root pests and pathogens, such as phytophthora root rot. Due to HLB’s widespread presence throughout Florida, root-health …
HLB and Citrus Root Health
“We’re not going to have a silver bullet” for HLB, says Lorenzo Rossi, an assistant professor at the Indian River Research and Education Center. Instead, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) root biologist says that researchers are trying to keep citrus producing profitably. Rossi described some of his research efforts that focus on root health …
Root Health Update
Evan Johnson, a University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) plant pathologist at the Citrus Research and Education Center, updates efforts to help citrus tree roots cope with HLB. He starts by noting that around 10 years ago he and former UF/IFAS researcher Jim Graham discovered “that HLB causes severe damage to the root system.” They hoped …
Micronutrients for Root Health and HLB
University of Florida researcher Jude Grosser, best known for his work on citrus breeding, has become a champion of micronutrients to improve root health and battle HLB. At a recent Highlands County OJ Break, he discussed the use of micronutrients, including why he got involved. “I guess just like any farmer, you don’t like watching your plants get sick and …
Influence of Rootstock on Growth, Productivity and Fruit Quality of Eureka Lemon
By Kim D. Bowman, Matt Mattia, Ranjeet Shinde and Flavia Zambon Profitability of the historic kings of citrus in Florida, sweet orange juice and fresh market grapefruit, has been severely reduced by the impact of huanglongbing (HLB) disease. Previous studies have demonstrated that lemon cultivars are generally more tolerant to HLB than sweet orange and grapefruit. Lemon trees continue cropping …
Study Highlights Soil pH Role in Citrus Tree Health
A new study examines the critical role soil pH plays in determining citrus root development, nutrient absorption and overall tree health. It offers insights for growers facing declining production challenges due to biotic restraints such as HLB disease and abiotic stresses such as low or high soil pH. The study looks at citrus root morphology across a range of soil …
Unraveling the Mechanisms Leading to Prolonged Tree Health by Combining IPCs and Brassinosteroids
By Fernando Alferez, Divya Aryal and Saoussen Ben Abdallah University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) research in the last three years has found that the combined use of individual protective covers (IPCs) and brassinosteroids (BRs) enhances protection of citrus trees against HLB and other diseases that limit citrus production in Florida. The research has been conducted …
Influence of Rootstock and OTC Injection on Valencia Yield
By Kim D. Bowman, Ute Albrecht and Caroline Tardivo Profitability of citrus in Florida has been severely reduced by the impact of huanglongbing disease (HLB). Previous studies have demonstrated that rootstock selection and injection of established trees with oxytetracycline hydrochloride (OTC) can both significantly improve the health, cropping and fruit quality of trees affected by HLB. However, neither a superior …
Boost Citrus Health and Yield With Silicon
By Muhammad A. Shahid and KeAndre Leaks Silicon (Si) is an emerging powerhouse in citrus production, offering wide-ranging benefits for plant health, fruit quality and stress resilience. While not traditionally considered essential, silicon was officially recognized as a “plant beneficial substance” in 2012 by the American Association of Plant Food Control Officials. Its inclusion as an approved input by the …
Brassinosteroids Improve HLB-Affected Tree Health and Fruit Quality
By Fernando Alferez, Divya Aryal and Saoussen Ben Abdallah In the last few years, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) citrus horticulture team at the Southwest Florida Research and Education Center (SWFREC) in Immokalee has performed several research trials in commercial farms and at the experimental farm at the SWFREC to elucidate the effect of …
Digging Into Methods to Boost Citrus Soil Health
By Sarah Strauss, Emma Dawson, Gabriel Pugina, Ute Albrecht, Jonas Pereira de Souza Junior and Davie Kadyampakeni While soil health has always been considered critical for Florida citrus production, it has increased in importance with the endemic presence of citrus greening (HLB). Soil health is similar to the concepts of soil quality or soil fertility but with an additional focus …
Citrus Health Forum Brings Together Growers and Researchers
By Maegan Beatty Earlier this month, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) North Florida Research and Education Center (NFREC) hosted the 2025 Citrus Health Forum. Growers gathered to learn about citrus production and hear regional citrus updates. Muhammad Shahid, UF/IFAS assistant professor, presented information on optimizing nitrogen fertilization to enhance the quality of satsuma mandarins. …
PIECES OF THE PAST: Polk County Roots Run Deep
By Brenda Eubanks Burnette I was honored this year to be part of the Vero Heritage Center and Indian River Citrus Museum’s “Deeply Rooted” event, which was the kick-off for Indian River County’s Centennial Celebration. It made me think of this year’s Florida Citrus Hall of Fame inductees. They all have something in common with deep roots — Polk County! …
Survey Shows Popular Scions and Rootstocks
The Florida Citrus State of the Industry Survey seeks input from growers on key issues affecting their groves. The survey has been conducted for many years, has tracked the trajectory of HLB and reported on production practices. While not a scientific survey, it has reflected general trends over the years. Last month, we published results on trunk-injection therapy and the …
Assessing Tools for Citrus Soil Health
Soil microbiologist Sarah Strauss on Jan. 28 discussed the benefits, challenges and unknowns of cover crops, compost and humic acid for citrus soil health. Strauss is a University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) associate professor at the Southwest Florida Research and Education Center. She pointed out that Florida’s citrus soils are problematic because they are 98% …
Combine IPCs and Brassinosteroids to Prolong Young Tree Health
By Fernando Alferez and Saoussen Ben Abdallah The risk of citrus plantings to become infected with HLB is especially high for young trees, which flush frequently and attract more psyllids than mature trees. Individual protective covers (IPCs) are now being increasingly adopted to protect newly planted citrus trees from psyllid colonization. However, even though IPCs effectively protect young trees from …
Study Shows Impact of HLB Bacterium on Roots
A recent study sheds light on the significant effects of Candidatus Liberibacter asiaticus (CLas), the bacterium responsible for HLB, on the root systems of grafted Valencia orange trees. The findings reveal that root system reductions caused by the infection are more extensive than the corresponding aboveground declines. That finding underscores the hidden yet critical impact of the disease below the …





























