By Lauren Diepenbrock In October 2018, a potential “new pest” was found in large numbers in one grove in Hernando County, Florida. The damage to trees was dramatic, with dark staining throughout the trunk of the tree and beetle damage evident. It was something that would put any grower, Extension agent or researcher on alert. Fortunately, by working with Jiri …
When to Be on Canker Alert
Citrus fruit is susceptible to canker after it reaches three-eighths of an inch in diameter, University of Florida Institute of Food and Agricultural Sciences Extension pathologist Megan Dewdney told growers this winter. “Once you get to that point and we get rain, then all bets are off as to whether you will keep canker out,” Dewdney said at a winter …
Fungal Foliar Disease Concerns for 2019
By Megan Dewdney The Florida citrus-growing seasons of 2017 and 2018 were quiet in terms of fungal foliar disease outbreaks. Small pockets of severe disease occurred sporadically, but there were no widespread reports of diseases like postbloom fruit drop, much to the relief of the industry. Greasy spot has flared up in a few locations on cultivars like Valencia, and …
Brown Rot Basics
Plant pathologist Megan Dewdney with the University of Florida Institute of Food and Agricultural Sciences discussed the basics of brown rot and its control at a recent disease seminar in Immokalee. Approximately 60 growers and others attended the seminar held at the Southwest Florida Research and Education Center. Brown rot is especially prevalent in early-season citrus varieties. “It’s particularly problematic …
Sneak Peek: February 2019 Citrus Industry Magazine
Disease defense is on the agenda for the February 2019 issue of Citrus Industry. University of Florida plant pathologist Megan Dewdney gives growers a fungal foliar disease forecast for this year. She warns that the risk of postbloom fruit drop is greater in 2019 than it was in 2017 and 2018. Other diseases she says growers should to be on …
PFD Threat Nears
“Postbloom fruit drop (PFD) season is coming upon us fairly quickly,” plant pathologist Megan Dewdney said in summarizing a presentation she made Jan. 16 in Immokalee, Florida. “Growers should be planning on keeping an eye on the rain forecast … how much bloom they are having now, how much bloom they’ll have in two (to) three weeks, and keeping an …
Thermotherapy’s Effects on Fruit Drop, Yield and Quality
By Megan Dewdney, Evan Johnson, Naweena Thapa and Michelle Danyluk In 2015, we started a large-scale project to determine if thermotherapy would be an effective huanglongbing (HLB) treatment for field trees. Some of the objectives were to determine effective temperature-time combinations for thermotherapy, which season gave optimal results for thermotherapy, and the effect on yield in subsequent years. TRIAL DETAILSComprehensive …
Citrus Advisory System May Help Prevent PFD Losses
A new University of Florida-developed forecasting system could help citrus growers control postbloom fruit drop this winter, despite the predicted El Niño weather pattern that’s expected to bring more rain and moderate temperatures. With an El Niño, forecasters expect above-average rain this winter and early spring. Increased rain improves the chances of fungal spores splashing from flower to flower in …
What to Do if Citrus Black Spot Isn’t Near
University of Florida Institute of Food and Agricultural Sciences researcher Megan Dewdney addresses what growers should do if citrus black spot isn’t near their groves. She summarizes a presentation she made at a recent growers’ workshop in Sebring. “My few pieces of wisdom have been to tell people to just be conscious of their area and know whether they are …
Hands-On Training Scheduled at UF/IFAS Citrus Workshop
Florida citrus growers will learn about the latest research from the University of Florida Institute of Food and Agricultural Sciences and test new technology at a workshop in Sebring, Sept. 25-26. UF/IFAS Extension Highlands County is working with statewide UF/IFAS Citrus Extension faculty to bring the latest in scientific studies and a hands-on learning experience to growers. Faculty will cover …
New Florida Citrus Production Guide Debuts at Citrus Expo
Beginning this week, Florida citrus growers will have an updated resource to help them keep groves productive despite the ever-present threat of huanglongbing, the bacterial malady also known as HLB or citrus greening disease. Experts with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) have just completed a 180-page technical handbook, “Florida Citrus Production Guide 2018-2019.” It …
Outlook for Postbloom Fruit Drop
By Megan M. Dewdney, Tripti Vashisth and Ariel Singerman In 2017, the damage from postbloom fruit drop (PFD) was lower than the previous three years. This was mainly due to the low rainfall accumulation in late winter and early spring. The long bloom with relatively few flowers at any one time made the decision of when to apply a fungicide …
Sweet Orange Scab Detected in Alabama
U.S. Department of Agriculture (USDA) officials have confirmed the first detection of sweet orange scab (SOS) in Alabama. The fruit sample was collected in Baldwin County by Alabama Department of Agriculture and Industries’ (ADAI) plant protection inspectors during a delimiting survey for citrus greening disease. The Auburn University Plant Diagnostic Clinic provided the initial diagnosis of SOS, and USDA Animal …
A Look Back at 100 Years of Citrus Innovation
By Beverly James, Alec Richman, Brad Buck, Samantha Grenrock and Tom Nordlie The year was 1917. In April, the United States entered World War I. Florida’s population was fast approaching 1 million, and agriculture was the state’s most important economic driver. Citrus cultivation, introduced to Florida 400 years earlier by Spanish explorers, had spawned an industry following the Civil War. …
Keeping Young Trees Free of HLB
Plant pathologist Megan Dewdney was one of the University of Florida Institute of Food and Agricultural Sciences researchers who summarized scientific presentations made at the 2017 International Research Conference on HLB. She and others spoke at an HLB Grower Day in Lake Alfred, putting the complex presentations into terms more understandable to those who aren’t scientists. Dewdney discussed young tree …
Will You Be Ready for Postbloom Fruit Drop?
By Megan M. Dewdney Again in 2016, postbloom fruit drop (PFD) caused widespread problems in Florida groves. There were multiple factors that contributed to the outbreak in 2016. The primary factor was likely the extended bloom that many saw because of a combination of tree stress caused by huanglongbing (HLB) and the very warm winter. Bloom in some groves was …
Sneak Peek: January Citrus Industry Magazine
A new year is just around the corner and so is the next issue of Citrus Industry magazine. The January issue features a cover story on Callie Walker, chief of the Bureau of Pest Eradication and Control for the Florida Department of Agriculture. Learn about Walker’s deep roots in citrus and what she is doing about the abandoned grove problem. …
Control of Stem-End Rot of Fresh Citrus
By Mark A. Ritenour, Jiuxu Zhang and Megan M. Dewdney Decay of fresh citrus fruit is most often caused by fungal pathogens that grow and develop in the hot and wet conditions typical in Florida. While green and blue molds (Penicillium digitatum and Penicillium italicum) and sour rot (Galactomyces citri-aurantii) are the most common postharvest citrus diseases worldwide, the subtropical …
Controlling HLB with Thermotherapy: What Have We Learned So Far?
By Reza Ehsani, Megan Dewdney and Evan Johnson In the last two years, many growers looked at thermotherapy as a way of keeping HLB-affected citrus trees in production until a more permanent solution could be developed. It has been shown that thermotherapy can kill HLB-causing bacteria under controlled environments. But the exact time and temperature is not known, and it …
New Knowledge on Citrus Black Spot
By Megan Dewdney, Jeff Rollins, Nan-Yi Wang and Ke Zhang Citrus black spot (CBS) has become established in the groves of Collier and Hendry counties. In other citrus-growing regions of the world where CBS is present, the sexual fruiting bodies of the fungus, known as pseudothecia, form in decomposing leaf litter. Approximately 50 to 180 days following leaf drop, the …