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Below you'll find a list of all posts that have been categorized as “Diseases”
The U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS) announced it has designated Alabama as a commercial citrus-producing area. This action provides Alabama with protections that are afforded under the citrus canker regulations applying to commercial citrus-producing states. USDA APHIS regulates the interstate movement of certain plants, plant parts and other articles from areas of the …
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 …
Australian scientists are developing a vaccine-like solution to arm citrus growers with an effective way to combat citrus tristeza virus (CTV), a significant challenge for the Australian citrus industry. The $1.5 million initiative is being delivered through Hort Innovation and collaboratively led by the University of Queensland, the New South Wales Department of Primary Industries (NSW DPI) and Auscitrus. Researchers …
By Ozgur Batuman Plant virus diseases are unusually difficult to manage if introduced into new production sites. Citrus-infecting viruses, particularly those spread by insect vectors, are no exception to this. Florida is regularly challenged by a barrage of invasive pests and pathogen species that could devastate the citrus industry. Viruses causing citrus leprosis and citrus yellow vein clearing diseases are …
Citrus canker was found for the first time in Georgia this past season. Unfortunately, it may be here to stay. Jonathan Oliver, University of Georgia (UGA) assistant professor and small fruits pathologist, talked about the disease during a citrus meeting in Valdosta, Georgia, on Aug. 9. He emphasized that Georgia producers may have to learn to live with the disease …
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 …
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 …
