By Megan Dewdney Every summer, a low rumble about algal spot reaches my ears. And every year, someone discovers it in their Florida grove for the first time. While this is a disease that is not always at the top of mind for growers, when you see it for the first time, it can be dramatic. DISEASE SYMPTOMS Algal spot …
Algal Spot an Increasing Problem in Florida Groves
Algal spot, not frequently seen in Florida citrus groves before 2015, has become more severe in recent years, University of Florida Institute of Food and Agricultural Sciences speakers reported Aug. 30. And the disease is likely to intensify as a problem with average temperatures increasing, said Megan Dewdney, associate professor of plant pathology at the Citrus Research and Education Center …
The Persistent Problem of Algal Spot
By Megan Dewdney Mid-summer to fall has become algal spot season in my office. The disease is re-emerging in Florida for unknown reasons. While much of the year algal spot is low key and hard to spot, between June and September it is very obvious. So, what is algal spot, should you be concerned, and what can you do about …
Prepare to Get Ahead of Algal Spot
By Megan Dewdney Last summer, I received many calls about algal spot, especially in late June to early July. Algal spot is a disease, caused by the algae Cephaleuros virescens, that occurs mostly on citrus tree limbs. Much of the year it is difficult to see because it is a gray-green color that blends into the color of citrus bark. …
What To Do About Algal Spot
By Megan Dewdney I did not need to visit my field trial to know that algal spot was in bloom on citrus in the last month. I have received many phone calls about it recently as growers notice the bright orange doughnuts on their tree limbs. For those unfamiliar with algal spot, it is a disease that occurs mostly on …
Phosphite Best for Algal Spot
Algal spot had rarely been seen in Florida groves until fairly recently, Megan Dewdney reported in a virtual Florida Citrus Growers’ Institute presentation. The University of Florida Institute of Food and Agricultural Sciences plant pathologist said she started hearing from concerned orange growers within the past five years. Those growers told her that copper, the historical recommendation for the disease, …
Algal Spot: A Re-emerging Disease
By Megan M. Dewdney Algal spot has not been seen frequently for many years, but in the last few years I have been getting more questions about identification and management. The disease is caused by a green alga, Cephaleuros virescens. The alga is not considered a parasite, as it grows superficially, but it does cause damage to trees if left …
Dealing With Disease: Canker, Black Spot and More
As the rainy season in Florida is set to begin, we caught up with Megan Dewdney to discuss citrus canker and other disease issues. Dewdney is a plant pathologist with the University of Florida Institute of Food and Agricultural Sciences. Q: How has the prevalence of citrus canker been in Florida in the past year or so? A: Dewdney: Citrus …
Symptoms and Management of Brown Rot and Greasy Spot
University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) presenters on Aug. 30 discussed symptoms and management of the fungal citrus diseases brown rot and greasy spot. Plant pathologist and associate professor Megan Dewdney, the featured speaker, focused on management. Multi-county citrus Extension agent Mongi Zekri, who hosted Dewdney’s talk, described disease symptoms. BROWN ROT Brown rot is usually …
Best Practices for Brown Rot Management
By Megan Dewdney The Florida rains have finally come this summer, just in time for early-season fruit to start the maturation process. This means there is some risk of brown rot in early sweet oranges and grapefruit. Much of Florida has been getting summer storms, wetting the soil. While this is excellent in general, the downside is that it allows …
All In For Citrus Podcast, June 2025
In the June All In For Citrus podcast, Michael Rogers gives an update on some of the activities keeping University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers busy this summer. Rogers is the director of the UF/IFAS Citrus Research and Education Center in Lake Alfred. One of their big projects is helping to coordinate the citrus seminars …
Sneak Peek: June 2025 Citrus Industry
The June issue of Specialty Crop Grower magazine honors the winner of the 2025 Citrus Achievement Award. Ben Albritton, this year’s recipient, is a fourth-generation citrus grower and Florida politician. Learn all about his career and accomplishments in the cover story. Don’t miss the digital edition of the magazine to see an exclusive video interview. Albritton and Specialty Crop Grower …
Brown Rot Could Be on the Horizon for Florida
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 …
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 …
Get the Newest UF/IFAS Info at the Citrus & Specialty Crop Expo
By Jamie Burrow and Ruth Borger Over the last several months, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) citrus team has been preparing for the annual Citrus & Specialty Crop Expo. The excitement is in the air as many faculty are preparing seminar presentations on valuable information that growers may use today to support their operations. …
Soil Is Key to Setting Up Trees for Success
By Brad Turner As I started my regenerative journey five years ago, it conjured up memories of walking the family groves in the 1970s with my freshly sharpened eye hoe. I would follow the tractor as it pulled the offset chopper, crisscrossing between the widely spaced trees in all directions. The native grasses and broadleaf plants — including legumes like …
Sneak Peek: February 2022 Citrus Industry
In the February issue of Citrus Industry magazine, Florida growers will find out what diseases to watch for this season. Megan Dewdney’s annual foliar fungal disease round-up reports on what some of the major problems are likely to be in 2022. The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) plant pathologist and Extension specialist provides tips on …
Pest Management: A New Approach to an Age-Old Challenge
By Brad Turner From a family with deep Florida roots, I have over 40 years of experience in commercial citrus production. I learned the industry from the ground up by working in the family groves while studying citrus production at Florida Southern College. I have owned a citrus nursery, my own groves and a citrus caretaking business. I have also …
Sneak Peek: February 2020 Citrus Industry Magazine
The February issue of Citrus Industry magazine lets growers know what diseases to be on the lookout for this season and how best to spot them in the grove. University of Florida (UF) researchers Megan Dewdney and Evan Johnson give citrus growers tips on planning for disease management in 2020 in their article. Citrus canker, greasy spot, melanose, black spot …
Payne Picked for 2019 Florida 500 List
Jack Payne, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) senior vice president of agriculture and natural resources, earned a spot on this year’s Florida 500, Florida Trend Magazine’s second annual list of the state’s most influential business leaders. Eighteen agricultural sector leaders made the list. “My recognition is really a reflection of UF/IFAS as a whole,” Payne …





























