phytophthora diseases

Phytophthora Diseases in California Citrus

Daniel Cooper California Corner, Diseases

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

Josh McGill Diseases

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?

Josh McGill Diseases, Research, 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

Josh McGill HLB Management, Research

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

Josh McGill Diseases, hurricane

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

Josh McGill 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

Josh McGill All In For Citrus Podcast, Diseases

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

Josh McGill California Corner, Diseases, Regulation

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

Josh McGill Citrus Expo, Diseases, IPCs

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

Josh McGill California Corner, Diseases

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

Josh McGill HLB Management, Research

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

Josh McGill Diseases, Florida, Fruit Drop

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

Ernie Neff Brazil, 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

Ernie Neff Research

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

Ernie Neff Pests

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 …

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Seeking Microbes for Disease Control

Ernie Neff Research

The next key to winning the battle against citrus diseases such as citrus canker may be in the tiniest microbes that live inside the citrus tree.  University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers hope to discover how these microbes may benefit citrus trees in their natural fight against diseases. The end result may be an environmentally …

Protecting Trees From Phytophthora Disease

Tacy Callies Diseases, Tip of the Week

By Evan G. Johnson It is time to start thinking about protecting the fall root flush that will start soon and continue through November/December. This is the largest root flush of the year that stores carbohydrate reserves for next spring. Coming out of the rainy season, phytophthora has had the chance to build up plenty of inoculum, especially in groves …

A Trojan Horse for Citrus Disease

Ernie Neff Diseases, Research

Scientists are hoping the RNA of an obscure infection can one day be used like a Trojan horse to deliver treatments to citrus trees, possibly to combat HLB disease. The infection, citrus yellow vein disease, was discovered 64 years ago in Riverside, California, and has never been seen elsewhere in the world. Decades later, University of California (UC) Riverside researchers …

Effects of Grower Tools on Citrus Diseases and Roots

Ashley Robinson Diseases, Root health

Citrus researchers at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) are taking a more comprehensive look at how tools to manage HLB affect young trees. The goal is to develop integrated approaches and update management practices for growers. After one year of the research project, some interesting results are already emerging. The research project, “Establishing Healthy …

The Challenge of Solving Citrus Tree Diseases

Ernie Neff Diseases

“When a tree gets infected, there is generally no way to cure it,” University of Maryland virologist Anne Simon wrote in a recent white paper about invasive tree diseases. She explained that trees lack adaptive immune systems, so once infected they typically must tolerate the pathogen for the remainder of their lifespan. “In some cases, immunity can be provided by …