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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’s Animal and Plant Health Inspection Service (APHIS) has revised the conditions for interstate movement of citrus fruit from areas quarantined for both sweet orange scab (Elsinöe australis, SOS) and citrus canker (Xanthomonas axonopodis, CC). The revisions allow for the movement of fruit to packinghouses located in contiguous states that are not quarantined for either disease. …
Alabama Cooperative Extension implores growers to be on the lookout for symptoms of citrus canker disease in their trees. Commercial growers need to scout their trees regularly to stop the disease’s potential spread, says Kassie Conner, Alabama Extension specialist. “What we need people to do right now is look for these symptoms and report it if they find it,” Conner …
By Christopher Vincent, Megan Dewdney and Liliana Cano Bingo is a relatively new and unfamiliar variety, which growers initially sought as a positive alternative. However, it presents some unique production challenges. Bingo is desirable because its high-quality, low-seeded fruits are ripe in October, a valuable harvest window for Florida growers. But in the early years of its propagation, some nurseries …
By Ozgur Batuman, Sanju Kunwar and Ana Redondo There are new products that potentially can be added to a grower’s toolbox in coming seasons for managing citrus bacterial canker. Citrus canker is an infection by a species of bacteria (Xanthomonas citri subsp. citri) that causes fruit blemishes and fruit drop. It makes fruit unsightly and lowers its marketability. Every year, …
The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) and the Texas Department of Agriculture (TDA) have established five new quarantine areas for citrus canker in Brazoria, Galveston and Harris counties, Texas. They also expanded two existing quarantine areas for citrus canker in Brazoria, Fort Bend and Harris Counties, Texas, to prevent the spread of the disease. …
By Megan Dewdney The 2021 foliar fungal season was an easier than average year. The La Niña weather pattern predicted last fall came to pass, and the spring was relatively dry from January to the end of May with some rain in February and April. While citrus trees in Florida were likely drought-stressed, the dry weather slowed the usual decomposition …
Citrus leprosis has not been reported in Florida since 1968, but researcher Ozgur Batuman called it “an approaching threat to Florida citrus” in a recent virtual seminar. Batuman, a citrus pathologist at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Southwest Florida Research and Education Center, urged growers to be on the lookout for the disease. According …
Phytophthora infection can lead to severe stunting in newly planted citrus trees, researcher Megan Dewdney told growers and others at a Jan. 19 presentation at the Citrus Research and Education Center in Lake Alfred, Florida. She said stunted trees never thrive or produce adequate fruit. Dewdney is a University of Florida Institute of Food and Agricultural Sciences plant pathologist. She …
The Citrus Research and Development Foundation (CRDF) governing board on Jan. 25 approved a project aimed at reducing fruit drop by using potassium, zinc, gibberellic acid and the herbicide 2,4-D in different timing scenarios. The funding will allow University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researcher Fernando Alferez to finish two years of work that CRDF Chief …
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. …
For the first time, scientists have been able to measure the speed of the Candidatus Liberibacter asiaticus (CLas) bacteria that causes HLB disease. CLas are injected into citrus trees by psyllids feeding on the trees’ sap. CLas relies on this sap to grow and spread throughout trees. Using a new statistical modeling analysis and measurement approach, plant pathologists were …
An update on citrus diseases in Brazil was part of a recent U.S. Department of Agriculture Foreign Agricultural Service (FAS) report. GREENING INCREASINGAccording to the 2021 citrus greening survey conducted by Fundecitrus, 43.4 million trees, or 22.37%, of the trees in the commercial area of the state of São Paulo and the western part of Minas Gerais are affected by …
A quarantine for Elsinoë australis, the fungal causal agent of sweet orange scab (SOS), was established in all of Baldwin and Mobile counties in Alabama to prevent the spread of the disease. The quarantine was established by the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) in cooperation with the Alabama Department of Agriculture and Industries (ADAI). …
In recognition of biosecurity threats such as HLB, a new five-year biosecurity program, CitrusWatch, has been launched in Australia. This program is funded by Hort Innovation through the citrus R&D levy and by Plant Health Australia (PHA) using the citrus plant health levy. The program is led by PHA, with Citrus Australia coordinating program activities. The Northern Territory Department of Industry Tourism …
Xylella fastidiosa (Xf) bacterium causes incurable diseases that make plants wither and possibly die, scorching and browning leaves and reducing the size of fruit in a wide variety of important crops. Citrus variegated chlorosis is among the diseases that Xf causes. Pablo J. Zarco-Tejada and Tomas Poblete with the University of Melbourne describe the Xf bacterium as “the number one …
Information to help growers find and control citrus black spot (CBS), as well as CBS regulatory procedures, were provided in an Oct. 26 training workshop in Arcadia. The workshop was hosted by multi-county citrus Extension agent Ajia Paolillo. University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) plant pathologist Megan Dewdney discussed the pest’s lifecycle, potential spread due to …
By Amit Levy Citrus leprosis is an exotic viral disease not currently present in Florida citrus, although the virus is present in non-citrus hosts. This disease was reported in citrus in Florida and Brazil in the early 1900s, where it caused great crop and tree losses, but was eliminated from Florida in the early 1960s. In recent years, the disease …
Effective immediately, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) is establishing three new quarantine areas and expanding two existing quarantine areas for citrus canker in Cameron County, Texas, to prevent the spread of the disease. This action is necessary because APHIS confirmed the positive identification of citrus canker in citrus trees from residential areas in …
The title of Megan Dewdney’s Citrus Expo presentation was, “Shorten the skirts? Whether skirting improves citrus black spot fungicidal management.” The answer was “no,” based on trials she conducted to make that determination. But while skirting doesn’t appear to improve citrus black spot (CBS) fungicide programs, she pointed out that “there are other good disease management reasons to skirt.” Dewdney …
A saturated summer across the Southeast means more potential for development of phytophthora root rot disease in citrus trees. The impact on Georgia’s young trees could be devastating, says Jonathan Oliver, University of Georgia assistant professor and small fruits pathologist. Oliver implores Georgia’s citrus producers to stay vigilant with their fungicide sprays, as the wet conditions have not let up. …
