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 …

New Plantings a Focus of Phytophthora Management

Josh McGill Diseases

Plant pathologist Megan Dewdney put emphasis on new plantings during a mid-March discussion of phytophthora management for citrus trees infected with HLB. Dewdney is a University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) associate professor at the Citrus Research and Education Center, where she spoke. Dewdney’s presentation was part of an OJ break hosted by UF/IFAS Extension multi-county …

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 …

Phytophthora Treatments for Hurricane-Damaged Groves

Josh McGill Diseases, hurricane, Tip of the Week

By Megan Dewdney A priority for the Florida citrus industry is evaluating groves for damage and determining the best course of action going forward after the destruction of Hurricane Ian. One of the many considerations is the effect of flooding on root health, particularly if standing water has remained longer than 72 hours. The main diseases are phytophthora foot, crown …

HLB Reduces Phytophthora Management Efficacy

Josh McGill HLB Management, Research

The pathogen phytophthora has long presented problems for Florida citrus growers. But the HLB disease that has plagued Florida since 2005 reduces the efficacy of phytophthora management, citrus pathologist Ozgur Batuman reported in a recent virtual seminar. Batuman, who works for the University of Florida Institute of Food and Agricultural Sciences, said improved fungicide timing, number of applications and rates …

Avoid Phytophthora When Planting

Josh McGill Diseases, Research

Phytophthora infection can lead to severe stunting in newly planted citrus trees, researcher Megan Dewdney told growers and others at a Jan. 19 presentation at the Citrus Research and Education Center in Lake Alfred, Florida. She said stunted trees never thrive or produce adequate fruit. Dewdney is a University of Florida Institute of Food and Agricultural Sciences plant pathologist. She …

Phytophthora Root Rot a Concern in Georgia Citrus

Tacy Callies Diseases

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. …

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 …

Plan Now for Phytophthora Season

Tacy Callies Diseases, Tip of the Week

By Evan Johnson The Florida citrus spring leaf flush is hardening off, which means the first root flush of the year is beginning. With the spring root flush comes thoughts of phytophthora foot rot. Spring roots are at particular risk in groves that had high phytophthora pressure last fall because many of the resting spores will start activating with the …

orange

Fight Phytophthora Root Rot in Citrus

Josh McGill Sponsored Content

Citrus growers need every available tool to fight disease, reduce tree stress and keep groves healthy against Phytophthora root rot. According to the University of Florida Institute for Food and Agricultural Sciences (IFAS), Phytophthora root rot is one of the most important diseases threatening citrus yield. This disease can be caused by different species within the genus Phytophthora, a water mold in the …

Phytophthora Root Rot Management

Tacy Callies Diseases, Tip of the Week

By Evan G. Johnson As September winds down, the fall root flush is starting and will 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 with a history of root …

Control Phytophthora in Citrus Crops

Josh McGill Sponsored Content

One of the most damaging pathogens for citrus crops continues to be Phytophthora, a soilborne pathogen that attacks the root systems and affects the entire citrus tree. As the pathogen degrades the tree’s root system, above ground symptoms such as slowed growth, chlorotic foliage and reduced fruit size intensify. Eventually, this may result in the death of the tree. Phytophthora can appear …

Control Phytophthora in Citrus Crops

Josh McGill Sponsored Content

One of the most damaging pathogens for citrus crops continues to be Phytophthora, a soilborne pathogen that attacks the root systems and affects the entire citrus tree. As the pathogen degrades the tree’s root system, above ground symptoms such as slowed growth, chlorotic foliage and reduced fruit size intensify. Eventually, this may result in the death of the tree. Phytophthora can appear …

Control Phytophthora in Citrus Crops

Josh McGill Citrus

One of the most damaging pathogens for citrus crops continues to be Phytophthora, a soilborne pathogen that attacks the root systems and affects the entire citrus tree. As the pathogen degrades the tree’s root system, above ground symptoms such as slowed growth, chlorotic foliage and reduced fruit size intensify. Eventually, this may result in the death of the tree. Phytophthora can appear …

Phytophthora: An Old Problem with New Challenges

Tacy Callies Diseases

By Evan Johnson Diseases caused by phytophthora continually threaten Florida citrus production. Brown rot can directly reduce yields of early maturing varieties including Hamlin and grapefruit, can delay harvest of fresh market fruit until infected fruit have dropped, or risk packinghouse rejection of the load because it can spread post-harvest. Foot and crown rot can kill trees but are uncommon …

HLB Tools for Today and Tomorrow

Josh McGill Citrus Expo, HLB Management

By Frank Giles and Tacy Callies The Citrus & Specialty Crop Expo hosted two citrus educational sessions during the Aug. 16–17 event held at the Florida State Fairgrounds in Tampa. The sessions included both long-term research aimed at delivering trees resistant to HLB as well as what growers can do today to help mitigate the effects of the disease in …

Diaprepes root wevil

Diaprepes Root Weevil Update for Florida

Josh McGill Pests

Florida’s populations of Diaprepes abbreviatus root weevil have been uncharacteristically low so far in 2023, entomologist Lauren Diepenbrock reported recently. The adult pests are normally active in April–May and in the fall, the University of Florida Institute of Food and Agricultural Sciences assistant professor noted. Prior to the discovery of HLB disease in Florida in 2005, growers who had extensive …

What To Do When Groves Flood

Josh McGill hurricane, Weather

By Mongi Zekri During heavy rains in the summer, excess water must be removed from the root zone. Flooding injury can be expected if the root zone is saturated for three days or more during extended summer rains at relatively high soil temperatures (86 to 95 degrees). Flooding during the cooler December–March period can be tolerated for several weeks at …

Brown Rot Could Be on the Horizon for Florida

Josh McGill Diseases, Tip of the Week

By Megan Dewdney It is summer in Florida, and the early fruit are maturing. This is always a risky time for brown rot in early sweet oranges and grapefruit cultivars. The summer rains have been happening, but they have been intermittent depending on location. This means that phytophthora propagule counts may vary depending on how much rain has occurred in …

Recovery Will Require a Multipronged Management Program

Josh McGill HLB Management, hurricane, Production

By Michael Rogers The 2022–23 Florida harvest season is now behind us. Yield losses magnified by the weather events this past season position the next couple of years as “make or break” for many growers. The lingering effects of hurricane Ian will impact next season’s crop as trees continue to recover and balance out canopy regrowth with fruit production. Despite …