By Megan M. Dewdney Postbloom fruit drop (PFD) is a sporadic flower disease. It is primarily caused by the fungus Colletotrichum acutatum. While infections only occur on flowers, the fungus is present on trees throughout the year. It survives by producing resting structures on leaves and stems. How the inoculum survives multiple years between infections is still unclear. The fungus …
Considerations for Managing Citrus Black Spot
In Florida, citrus black spot (CBS) is present primarily in commercial groves in five southwest counties (Charlotte, Collier, Glades, Hendry and Lee). The disease can cause up to 60% yield loss in severe situations with little management, researcher Megan Dewdney reported in January. More commonly though, growers with infestations experience fruit drop levels of 10% to 20% in a minimally …
Sneak Peek: February 2023 Citrus Industry
With more growers incorporating compost and organic amendments into their production, weed management is receiving increased attention. University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) authors Ramdas Kanissery and Mahesh Bashyal take on this topic in their article in the February 2023 issue of Citrus Industry magazine. While compost and organic amendments can increase soil health and boost …
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 …
$21.7 Million for HLB Research
Seven entities recently received $21.7 million to conduct research into combating and preventing HLB at the farm level. The funding is from the U.S. Department of Agriculture’s National Institute of Food and Agriculture (USDA NIFA) Emergency Citrus Disease Research and Extension program. The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) received the majority of the funding, more …
Citrus Canker and Black Spot Management After Hurricane Ian
By Megan Dewdney The story of citrus canker in Florida is unfortunately linked to hurricanes. Canker spreads far and wide with the aid of the storms. Not only can the heavy rains and high winds move the bacterium among locations, but the winds cause wounds in the canopy. Ragged leaves, scoring of leaf surfaces, thorn scratches on branches and more …
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 …
Phytophthora Treatments for Hurricane-Damaged Groves
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 …
All In For Citrus Podcast, October 2022
The October All In For Citrus podcast focuses on Hurricane Ian and its impact on the state’s signature crop. The storm tore a path across Florida’s citrus-growing regions, causing hundreds of millions of dollars in damage. Michael Rogers, director of the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education Center, provides details on how …
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 …
Florida Black Spot Quarantine Expanded
Federal and state agriculture officials have expanded the citrus black spot (CBS) quarantine area in Florida. They have added four sections in Collier County and five sections in Glades County. The action was taken by the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) in cooperation with the Florida Department of Agriculture and Consumer Services Division of …
Pests, Pathogens and IPCs
By Lauren Diepenbrock, Megan Dewdney, Fernando Alferez, Jawwad Qureshi and Ozgur Batuman Individual protective covers (IPCs) are becoming commonplace in citrus production to support the development of young trees after planting. IPCs are made of fine mesh and are intended to keep Asian citrus psyllids (ACP) off young plants. Because ACP can transmit the pathogen that causes citrus greening/huanglongbing, preventing …
Don’t Forget Citrus Black Spot in Florida
While HLB tops the agenda, Megan Dewdney, an associate professor of plant pathology and an Extension specialist with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), reminded growers that citrus black spot (CBS) remains a concern. This was the topic of a presentation she made during the Florida Citrus Growers’ Institute held in Avon Park in April. …
Greasy Green Research Approved
Due to the initiative of the Indian River Citrus League (IRCL), the Citrus Research and Development Foundation (CRDF) has approved research funding for the greasy green defect on citrus fruit. At a 2021 IRCL board meeting, the issue of greasy green spot was brought up by Tim Sallin of IMG Citrus. Other growers at that meeting also shared their experience …
Research Update: Stable Antimicrobial Peptide
By Hailing Jin Research on the effectiveness of a novel stable antimicrobial peptide (SAMP) identified from the Australian finger lime (Microcitrus australasica) to fight huanglongbing (HLB) continues in a multistate initiative involving 1,500 citrus trees. Although the pandemic has impacted the progress of the research, work has steadily continued and expanded. Researchers at the University of California, Riverside and University …
How to Reduce Bingo Tree Loss to Stem Dieback
By Christopher Vincent, Megan Dewdney and Liliana Cano Bingo mandarin hybrid is a variety with many promising characteristics, but it brings specific challenges to profitable production. One challenge identified early in the push to plant Bingo was stem dieback that led to tree loss. After looking into this problem for the past four years, University of Florida Institute of Food …
Battling Black Spot
By Megan Dewdney Editor’s note: This article originally stated that citrus black spot was in Hardee County. It should have said Hendry County, and has now been corrected. Citrus growers in Florida continue to battle new pests and diseases. They have been learning to manage citrus black spot for the last 12 years. The disease is still localized mainly in …
Comparison of ACP/HLB Management Tools for Citrus Resets
By Lauren Diepenbrock, Megan Dewdney, Christopher Vincent and Davie Kadyampakeni As the threat of potential shutdowns loomed in March 2020, a University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) team put the final plants in the ground, individual protective covers (IPCs) on trees, and kaolin and pesticide applications on a 2.7-acre planting at the Citrus Research and Education …
Fruit Size and Spraying Interval Are Key for Canker Control
The size of fruit that should be sprayed, the spraying interval and ways to avoid copper phytotoxicity were among the citrus canker topics plant pathologist Megan Dewdney offered growers recently. Dewdney said fruit are most susceptible to canker when they are between 3/8 inch and 1.5 inches in diameter. The fruit rind becomes much more resistant when the fruit is …
‘Irma Will Haunt Us’ Regarding Citrus Black Spot
Citrus black spot (CBS) disease has only been found in five Southwest Florida counties, but that could change as a result of 2017’s Hurricane Irma, a researcher reiterated recently. University of Florida Institute of Food and Agricultural Sciences plant pathologist Megan Dewdney, in a Feb. 24 presentation, said “Irma will haunt us for a while.” She explained that Irma likely …