By Manjul Dutt, Sheetal Ramekar and Gary England The grapefruit was created by chance from a cross between a pummelo and a sweet orange. It was first discovered in Barbados in the 18th century. All the commercially sold grapefruits today trace their roots back to the Duncan variety of grapefruit. Cultivars existing today were developed through natural and induced mutations …
HLB Confirmed on California Inactive Citrus Acreage
The California Department of Food and Agriculture (CDFA) has confirmed the detection of the citrus plant disease huanglongbing (HLB) in inactive citrus acreage in the city of Yorba Linda, Orange County. The detections mark the first time HLB has been confirmed in plant samples on non-residential, non-nursery citrus acreage. The detection site, which is not currently operational or being cultivated …
California HLB Quarantine Expanded
Agricultural officials recently expanded the areas in California quarantined for citrus greening disease [also known as huanglongbing (HLB)], which is spread by Asian citrus psyllids. The quarantined area in Orange and Riverside counties was increased by a total of approximately 31 square miles. The U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) in cooperation with the …
Australian Lime Interstocks to Combat HLB
By Ozgur Batuman, Sanju Kunwar and Ana Redondo In a promising effort to protect citrus from huanglongbing (HLB), University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers are exploring the potential of Australian lime as an interstock graft for Valencia scions with Swingle rootstock. The interstock technique uses various limes, known for their natural HLB-tolerant peptides, between the …
Top Pruning Evaluated as HLB Strategy
A Brazilian study evaluated the effects of top pruning on orange trees located on the edges of an orchard as part of an HLB management strategy. The pruning was an attempt to attract the HLB-spreading psyllid from external areas to the orchard edges and control it, reducing its dispersion into the orchard. Fundecitrus and Embrapa Cassava and Fruits conducted the …
Brazilians Visit Indian River to Learn About HLB Management
Several citrus growers, consultants and others from São Paulo, Brazil, recently toured Florida’s Indian River citrus region to examine the management of HLB. Flavia Zambon, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) assistant professor of horticultural production at the Indian River Research and Education Center (IRREC), hosted the group. “In the traditional production region known as the …
A Simpler, Safer and More Effective Way to Fight HLB
Many Florida citrus growers view new trunk-injection therapies as a lifeline to help them stay viable in the ongoing battle against HLB. After two seasons of trunk-injection applications of oxytetracycline (OTC), growers are evaluating the impacts on tree health, production and quality. Heading into next season’s treatment cycle, now is the time to consider product options. Factoring into this decision …
Immediate Response Required When Managing HLB
The first chore for growers in the cold-hardy citrus region when managing citrus greening is scouting for the disease and its vector, the Asian citrus psyllid. The next step is prompt removal of any trees infected with the disease, says Jonathan Oliver, University of Georgia (UGA) assistant professor and small fruits pathologist. “At this point, we think greening is still …
Citrus-Derived Endophytes Have HLB Management Potential
Florida-based scientists published an article in Microorganisms indicating citrus-derived endophytes have potential for managing HLB. Endophytes are endosymbionts, often bacteria or fungi, which live within a plant for at least part of its life cycle without causing apparent disease. The authors of the article are Jessica Dominguez, Krishnaswamy Jayachandran and Kateel G. Shetty of Florida International University, and U.S. Department …
HLB-Tolerant Scion Breeding Update
U.S. Department of Agriculture-Agricultural Research Service (USDA-ARS) geneticist Matt Mattia with the U.S. Horticultural Research Laboratory in Fort Pierce, Florida, recently provided a scion breeding update on HLB-tolerant citrus. A slightly edited version follows: Significant strides are being made in the development and evaluation of new citrus varieties, with many now nearing commercial release. These varieties are not only promising …
HLB at Center of Florida Citrus Breeding Efforts
Peter Chaires, New Varieties Development and Management Corp. executive director, spoke about citrus breeding at the Cold Hardy Citrus Workshop on Sept. 24 at the University of Florida Institute of Food and Agricultural Sciences Extension office in Perry. Chaires said HLB tolerance “is an essential element of everything that’s being done in the breeding program with a stronger emphasis than …
Commercial Citrus Impacted by Expanded HLB Quarantine
The area quarantined for HLB in San Diego County, California, has been expanded, the U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) announced on Sept. 23. USDA APHIS took the action in cooperation with the California Department of Food and Agriculture (CDFA). HLB, a plant disease caused by Candidatus Liberibacter asiaticus, is also known as citrus …
HLB Incidence Exceeds 44% in Brazil’s Citrus Belt
Fundecitrus’ annual survey of HLB in Brazil indicates that disease incidence rose from 38.06% in 2023 to 44.35% in 2024 throughout the Citrus Belt of São Paulo and Triângulo/Southwest Mineiro. This is the seventh consecutive year of growth for the disease. HLB was found in approximately 90.36 million trees. In total, there are 203.74 million orange trees throughout the Citrus …
Frequent Irrigation Benefits HLB-Infected Sweet Orange Trees
By Tripti Vashisth and Mary Sutton Citrus trees affected by huanglongbing (HLB) show significant root dieback. This dieback results in smaller root systems than would be seen in healthy citrus trees. These small root systems are limited in their uptake capacity. In other words, if an HLB-affected tree is given the same amount of water as a healthy tree, the …
HLB and Psyllids in Georgia Commercial Citrus
One of Georgia citrus growers’ worst fears is slowly becoming a reality. Citrus greening, also known as huanglongbing (HLB), was observed in a Georgia commercial citrus grove for the first time in 2023. This is alarming news for the industry, says Jonathan Oliver, University of Georgia (UGA) assistant professor and small fruits pathologist. “We knew HLB was here in residential …
Heat and HLB Hurting Brazil’s Production
Brazil’s citrus crop is suffering this season, according to Franklin Behlau, a senior researcher for Fundecitrus. That was the focus of a recent presentation he provided at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center in Lake Alfred. “Things have changed in Brazil this season,” Behlau said. “We are a little behind …
HLB Product Advancing in Registration Process
Silvec Biologics announced that an RNA vector delivery product to combat HLB has progressed to the Full Science Review Phase of the Environmental Protection Agency (EPA) Pesticide Regulation Improvement Act registration process. The product was developed in collaboration with Southern Gardens Citrus (a subsidiary of U. S. Sugar), the University of Florida (UF) and Texas A&M AgriLife Research. Silvec is …
Sustaining Citrus Production in the HLB Era
The virtues of daily irrigation and increased micronutrient applications were among key points researcher Davie Kadyampakeni made in an Aug. 13 discussion of citrus production in the HLB era. Kadyampakeni is a University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) associate professor of soil, water and ecosystem sciences at the Citrus Research and Education Center in Lake Alfred. …
New HLB Publication at the Citrus & Specialty Crop Expo
By Michael E. Rogers Do you plan to attend the Citrus & Specialty Crop Expo on Aug. 21–22 at the Florida State Fairgrounds in Tampa? If so, you’ll want to stop by the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Extension booth to pick up the latest publication on HLB management assembled by UF/IFAS citrus experts. …
Reasons to Believe HLB Is Beatable
Growers gathered in Bonita Springs in mid-June for the Florida Citrus Industry Annual Conference. The event hosted by Florida Citrus Mutual drew a good crowd. The mood of growers was mixed. While there was hope that HLB trunk-injection therapies might have resulted in more dramatic improvements to this year’s crop, there also was recognition that these therapies represent one of …