Not all citrus disease concerns center around huanglongbing (HLB). While HLB disease garners much of the headlines because of its devastation to Florida’s citrus crop, growers in the cold-hardy citrus region should be mindful of other diseases that can devastate a crop if left untreated. Jonathan Oliver, University of Georgia (UGA) assistant professor and small fruits pathologist, highlighted some of …
Post-Hurricane Disease Concerns
Phytophthora, citrus black spot and HLB are among diseases that could be spread in Florida groves as a direct or indirect result of Hurricane Milton, researcher Megan Dewdney cautioned. Dewdney, a University of Florida Institute of Food and Agricultural Sciences associate professor of plant pathology, offered suggestions for dealing with those diseases during a recent hurricane recovery webinar. PHYTOPHTHORA Phytophthora …
The Florida Citrus Perfect Storm: Disease, Weather and Market Swings
By Ariel Singerman Orange yield in Florida has decreased by more than 80% since HLB was first found in the state in 2005. It is hard to find another example in recent history of an industry as iconic as Florida citrus that has declined so significantly as a consequence of a plant disease. As a comparison, at the global level, …
Citrus Disease Quarantines Expanded in California
U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA/APHIS) officials, in cooperation with the California Department of Food and Agriculture (CDFA), recently expanded the areas quarantined for huanglongbing (HLB) and sweet orange scab (SOS) in the state. HLB The quarantined area in Los Angeles, Orange and Riverside counties has been expanded by approximately 50 square miles. Additionally, the …
Diseases Easier to Prevent Than to Control
Plant pathologist Ozgur Batuman recently warned that two citrus viral diseases not currently in Florida are highly suited to the state’s climate and would likely impact production if found there. They are citrus leprosis and citrus yellow vein clearing virus (CYVCV). Batuman, a University of Florida Institute of Food and Agricultural Sciences associate professor at the Southwest Florida Research and …
Phytophthora Diseases in California Citrus
Greg Douhan with University of California Agriculture and Natural Resources (UCANR) recently wrote about phytophthora diseases in California citrus. Edited excerpts follow: There are at least four species of Phytophthora species (P. citrophthora, P. parasitica, P. syringae and P. hibernalis) associated with citrus in California. The three diseases in citrus caused by these fungal-like pathogens are phytophthora root rot, phytophthora …
Diseases Without Borders: Leprosis and Yellow Vein Clearing Viruses
By Ozgur Batuman Plant virus diseases are unusually difficult to manage if introduced into new production sites. Citrus-infecting viruses, particularly those spread by insect vectors, are no exception to this. Florida is regularly challenged by a barrage of invasive pests and pathogen species that could devastate the citrus industry. Viruses causing citrus leprosis and citrus yellow vein clearing diseases are …
Can Brassinosteroids Help Citrus Cope With Disease and Extreme Weather?
By Fernando Alferez and Muhammad A. Shahid Brassinosteroids (BRs) are a natural group of hormones that regulate physiological and biochemical attributes that include seed germination, flower development, root formation and resistance to various abiotic and biotic stresses. BRs have shown promise in reducing pests and diseases in a wide range of plants, including citrus. A commercial formulation of BRs has …
Lessons Learned From HLB as an Immune-Mediated Plant Disease
By Nian Wang How the huanglongbing (HLB) pathogen Candidatus Liberibacter asiaticus (CLas) causes damage to infected citrus trees has been widely debated. A recent study demonstrates that HLB is an immune-mediated plant disease (Ma et al., 2022). It was discovered that CLas infection of citrus stimulates systemic and chronic immune response in phloem tissues, including reactive oxygen species (ROS) production, …
Post-hurricane Expectations for Foliar Diseases and Phytophthora
By Megan Dewdney For foliar diseases, 2022 started off easily with limited outbreaks in Florida because the spring was dryer than average. The same La Niña weather pattern responsible for the dry conditions of the last two springs is predicted to occur again this winter into early spring. The weather pattern is then predicted to become a neutral pattern with …
Updates on Florida Citrus Diseases
Researcher Megan Dewdney recently provided updates on citrus canker, postbloom fruit drop (PFD) and algal spot. Dewdney is a University of Florida Institute of Food and Agricultural Sciences associate professor of plant pathology at the Citrus Research and Education Center. CANKERFruit is most susceptible to canker when it is from 3/8 to 1.5 inches in diameter, Dewdney said. The fruit’s …
Post-Hurricane Disease Management Advice
Megan Dewdney, associate professor of plant pathology with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), joined the October All In For Citrus podcast to discuss Hurricane Ian and tips on disease management after the storm. Hurricanes weaken citrus trees and spread disease. “If a tree has a full canopy, the wind will put a lot of …
Regulatory Response to New Citrus Disease Being Developed
State and federal officials are collaborating in the development of a regulatory response to a new citrus disease in California. Citrus yellow vein clearing virus (CYVCV) was identified in the city of Tulare in March. The discovery is the first instance of the disease in the United States. The California Department of Food and Agriculture (CDFA) and the U.S. Department …
How Different Techniques Hold Up to Diseases
How well reflective mulch, kaolin clay and individual protective covers (IPCs) hold up to HLB, canker and greasy spot diseases was researcher Megan Dewdney’s topic at the 2022 Citrus & Specialty Crop Expo. Dewdney is a University of Florida Institute of Food and Agricultural Sciences associate professor of plant pathology at the Citrus Research and Education Center. The research project …
California Seeks Funding for CYVCV Disease
With citrus industry backing, California state legislators have requested $2.5 million in emergency state funds to help prevent the spread of citrus yellow vein clearing virus (CYVCV). The first finding of the new disease in the United Sates was recently made in Tulare, California. Casey Creamer, California Citrus Mutual (CCM) president and chief executive officer, said the statewide grower organization …
Pests and Diseases in Trees With IPCs
All indications are that the recent widespread use of individual protective covers (IPCs) on young citrus trees in Florida is beneficial, especially for excluding Asian citrus psyllids and the HLB they spread. If there is any downside, it may be that some other pests and diseases are more prevalent under IPCs. In a recent American Society for Horticultural Science webinar, …
Foliar Fungal Disease Round-up for 2022
By Megan Dewdney The 2021 foliar fungal season was an easier than average year. The La Niña weather pattern predicted last fall came to pass, and the spring was relatively dry from January to the end of May with some rain in February and April. While citrus trees in Florida were likely drought-stressed, the dry weather slowed the usual decomposition …
An Update on Brazil’s Citrus Diseases
An update on citrus diseases in Brazil was part of a recent U.S. Department of Agriculture Foreign Agricultural Service (FAS) report. GREENING INCREASINGAccording to the 2021 citrus greening survey conducted by Fundecitrus, 43.4 million trees, or 22.37%, of the trees in the commercial area of the state of São Paulo and the western part of Minas Gerais are affected by …
Rancid Oranges Aid Detection of Diseases
A University of Sydney researcher is developing a cancer and serious disease-detecting biomedical probe that can be made from the juice of rancid oranges. Called a nanobiosensor — a tiny probe that uses fluorescence to signal cells’ pH in terms of their acidity or alkalinity — it detects whether cells are at risk, or in the early stages of cancer …
Protecting Citrus From Pests and Diseases
The federal Plant Protection and Quarantine (PPQ) program summarized its efforts to protect the U.S. citrus industry from pests and diseases in a recent report about its fiscal year (FY) 2020 activities. PPQ is part of the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service. A summary of its citrus efforts follows. PPQ works with citrus growers to …