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Below you'll find a list of all posts that have been categorized as “Diseases”
Brazil’s Fundecitrus is alerting citrus growers to take extra measures against leprosis during the current critical period for disease occurrence, May to September. At this time, fruit are in development, and the lack of rain favors outbreaks of the leprosis-transmitting mite. Leprosis is an important disease of Brazilian citrus that in recent years has caused significant damage to orange groves. …
University of Florida Institute of Food and Agricultural Sciences researchers Megan Dewdney, Mark Ritenour, Liliana Cano, Eva Mulandesa and Monty Myers recently provided an update of their greasy-green disorder research. Excerpts follow from the Indian River Citrus League’s River Ramblings publication: “Greasy green” is a term applied to fruit that develop what appears to be greasy spot rind blotch symptoms …
A California researcher recently provided an update on sweet orange scab (SOS). The fungal disease has been detected in the state 18 times since 2013. University of California, Riverside professor and plant pathologist Jim Adaskaveg said most of the detections have been in Southern California, especially in Imperial County. Eleven detections have been in commercial lemon orchards, three in commercial …
In a recent webinar, Jim Adaskaveg, University of California, Riverside professor and plant pathologist, discussed some recently registered fungicides to manage phytophthora and other fungal diseases of citrus. Orondis was registered in 2018, Presidio in 2019 and Revus in 2020. Adaskaveg said Orondis and Revus each contain a new active ingredient with a different mode of action and provide a …
Citrus black spot (CBS) disease was confirmed at a second location in Florida’s Polk County in March. The new find was in a grove near State Road 60 and Indian Lake Estates, east of Lake Wales. The only prior CBS infestation in Polk County was near U.S. 27 on the Highlands County border. But that location was turned into an …
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 …
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 …
In Brazil’s São Paulo citrus belt, infections of fruit by black spot usually occur from petal fall, in September/October, until the end of the rainy season, usually in April. Black spot can reduce production by up to 85%. Some studies have shown that the amount of fungicide applications to control black spot can be established according to the orange variety. …
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 …
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 …
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 …
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 …
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 …
Two new detections of citrus yellow vein clearing virus (CYVCV) have been confirmed in rural residential citrus trees in the city of Visalia in Tulare County, California. The detections resulted from an ongoing survey and sampling activities conducted by the California Department of Food and Agriculture (CDFA). CYVCV had previously been confirmed in August in the city of Tulare; learn …
Although trunk injection of oxytetracycline hydrochloride (OTC-HCl) has received much recent press for its promise in managing HLB, there is still no silver bullet for the devastating disease. That was part of plant pathologist Ozgur Batuman’s message at a Dec. 10 seminar addressing HLB and other citrus diseases that may exacerbate HLB’s effects on trees. “There is no single effective …
Brazilian citrus association Fundecitrus has alerted growers that proper management to combat citrus canker in orchards begins with leafminer control. The leafminer is a pest that has been present in Brazilian citriculture since 1996. According to Fundecitrus researcher Franklin Behlau, the leafminer does not spread citrus canker disease from one plant to another or even to different parts of it. …
The December All In For Citrus podcast includes a discussion with Michael Rogers, director of the Citrus Research and Education Center, about ongoing efforts growers are making to rehabilitate citrus groves after Hurricanes Ian and Nicole. Rogers also addressed some longer-term research being conducted by the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) to develop trees that …
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 …
The element silicon, known to be beneficial to many plants, is being evaluated for advantageous effects on North Florida citrus and blackberries. Horticulturist Muhammad Shahid discussed the benefits of Earth’s second-most-abundant element (after oxygen) during a recent Cold-Tolerant Citrus Production Workshop in Perry, Florida. Shahid is a University of Florida Institute of Food and Agricultural Sciences assistant professor at the …
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 …
