Back in the early days of the HLB fight, it was observed that what is going on underground in citrus tree root systems is just as important as what is happening aboveground. In 2013, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) and U.S. Department of Agriculture-Agricultural Research Service researchers published that 27% to 40% root loss due …
Growing Citrus With Soil Health in Mind
Herb Young enjoyed a 40-year career in the agricultural chemical industry, starting as a technical service representative and eventually becoming a product manager. During those years, he worked on various specialty crops across the country. About 25 years of his career was spent in field research roles. So, experimentation with crops and growing practices comes naturally to Young. He has …
Breeder Advice on Nutrition, Scions and Rootstocks
Citrus breeder Jude Grosser recently shared tips on tree nutrition and discussed some scion/rootstock combinations that should work well for trees producing juice oranges. NUTRITIONGrosser became very interested in citrus nutrition several years ago in an effort to keep his newly bred trees healthy in the face of HLB. The University of Florida Institute of Food and Agricultural Sciences professor …
Hairy Approach May Get to the Root of HLB
Developing disease-resistant, high-quality improved crop varieties may seem like a “hairy” task, but Texas A&M AgriLife Research scientists may have gotten to the root of the issue. A new biological technology that develops and multiplies disease-resistant citrus plants is under development by an AgriLife Research team led by Kranthi Mandadi. Mandadi is an associate professor at the Texas A&M AgriLife Research …
USDA Citrus Breeding Program Focused on Rootstock and Variety Solutions
The U.S. Department of Agriculture’s (USDA) U.S. Horticultural Research Laboratory in Fort Pierce, Florida, has been home to a citrus rootstock and variety breeding program for many years. Kim Bowman, a research geneticist, has been with the program for more than 30 years. More recently, Matthew Mattia, a geneticist, joined the breeding team. They provide an update on the program …
Using Cover Crops to Improve Soil Health
By Sarah Strauss, Emma Dawson and Elena Karlsen-Ayala The term “soil health” has become increasingly popular in the last several years. While there are many definitions of soil health, one of the more commonly cited ones is from the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS). It defines soil health as “…the continued capacity of a soil …
Citrus Root Weevil Intercepted
U.S. Customs and Border Protection (CBP) agriculture specialists intercepted a species of citrus root weevil for the first time in Wilmington, Delaware, on May 22. They found the Cleistolophus viridimargo (Champion, 1911) weevil, a significant actionable pest, while inspecting a shipment of pineapples from Honduras. CBP said citrus root weevils pose a serious threat to the $3.4 billion U.S. citrus …
Valencia on US-942 Rootstock Is Favored Florida Tree
For at least the last four years, the Valencia SPB-1-14-19 orange has been the most-produced citrus variety in Florida, and US-942 has been the favored rootstock. So, it makes sense that the Valencia SPB-1-14-19 on US-942 rootstock has been the most-produced tree combination for four years running. That information was provided at April’s Florida Citrus Growers’ Institute in Avon Park …
Cytokinin Studied for Citrus Health Benefits
Tripti Vashisth, University of Florida Institute of Food and Agricultural Sciences associate professor, has been leading the research on how plant growth regulators (PGRs) can improve the health of HLB-infected trees. She’s conducted extensive research on the use of gibberellic acid. But she has recently begun to study another hormone, cytokinin. She gave an update on this work during the …
Citrus Root Structures: Lessons From Below
By Ute Albrecht There have been numerous reports of malformed roots in field-grown citrus trees recently. The rootstock propagation method is often suspected as the culprit. Before drawing quick conclusions, it is important to recognize that there are many different factors that can influence the root structure of a citrus tree aside from the propagation method. These include the genetic …
Progress in Developing Improved Citrus Rootstocks to Mitigate HLB
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 …
An Update on Oak Mulch to Increase Soil Health
By Lukas M. Hallman, John M. Santiago and Lorenzo Rossi At first glance, one may not see how oak trees relate to citrus production. But in the early 2010s, growers and scientists reported seeing little to no HLB symptoms on citrus growing underneath the dripline of oak trees compared to citrus trees nearby but not directly under oak trees. These …
Consistency Is Key in Rootstock Field Trials
By Bill Castle Today, at least three things seem to be true about Florida citrus rootstock field trials: There is an unprecedented number of them underway or soon to be planted. The sponsors are many, including the University of Florida, U.S. Department of Agriculture, Citrus Research and Development Foundation, Citrus Research and Field Trial Foundation and the Multi-Agency Coordination Group. …
Dealing With Diaprepes Root Weevils
By Ajia Paolillo Managing diaprepes root weevils in the grove is essential for root health and overall tree health. The most concerning root weevil for citrus growers is Diaprepes abbreviatus. Diaprepes larval feeding causes significant injury and damage to citrus root systems. LIFE CYCLE AND FEEDING Let’s begin with the life cycle stages of the diaprepes root weevils. Adults emerge …
Which Rootstock to Select
Valencia trees on high-vigor (left) and low-vigor (right) inducing rootstocks in a Central Ridge field trial. Note the higher yield efficiency of the smaller trees on the right and the leaning of these trees due to Hurricane Irma. By Ute Albrecht Rootstock selection is critical for longevity and productivity of a grove. The decision should be based on compatibility with …
Researchers Share Tree Health Suggestions
University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers gave a crowd of growers suggestions that can help keep citrus trees healthy. The panel discussion was part of the Nov. 16 open house and field day at the UF/IFAS Citrus Research and Education Center in Lake Alfred. HLB-affected trees need enhanced nutrition “throughout the growing season,” said horticulturist …
Graft Compatibility of New Scion−Rootstock Combinations
By Ute Albrecht, Bo Meyering, José Chaparro and Kim D. Bowman Grafting is an ancient horticultural technique. There is evidence of citrus grafting in the Roman era dating back to the fifth century. In western Europe, grafting was regularly practiced in the 16th and 17th centuries when citrus was grown as an exotic ornamental in containers in orangeries. In Florida, …
Phytophthora Root Rot a Concern in Georgia Citrus
A saturated summer across the Southeast means more potential for development of phytophthora root rot disease in citrus trees. The impact on Georgia’s young trees could be devastating, says Jonathan Oliver, University of Georgia assistant professor and small fruits pathologist. Oliver implores Georgia’s citrus producers to stay vigilant with their fungicide sprays, as the wet conditions have not let up. …
Citrus Canopy Health Is Highly Important for HLB Tolerance
By Amit Levy and Tripti Vashisth In Florida, where almost all citrus trees are infected with huanglongbing (HLB), it is important to have an easy and reliable method to check the severity of the disease. Each tree responds differently to Candidatus liberibacter asiaticus (CLas), the bacterial pathogen that causes HLB. Compare it to COVID-19, where some people had the virus …
Indian River Millennium Block Shows Rootstock Effects
By Rhuanito S. Ferrarezi, J. Martin Zapien-Macias, Mac Hossain, Tom James, Ronald D. Cave, Peter Spyke, William S. Castle, Jude W. Grosser, Fred Gmitter and Ed Stover In the last decade, huanglongbing (HLB) has reduced production of Florida grapefruit by 75%, mandarin by 78% and sweet orange by 52%. This decrease is significant for the Indian River District, which produces …





























