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Below you'll find a list of all posts that have been categorized as “Diseases”
By Megan Dewdney Editor’s note: This article originally stated that citrus black spot was in Hardee County. It should have said Hendry County, and has now been corrected. Citrus growers in Florida continue to battle new pests and diseases. They have been learning to manage citrus black spot for the last 12 years. The disease is still localized mainly in …
By Lauren Diepenbrock, Megan Dewdney, Christopher Vincent and Davie Kadyampakeni As the threat of potential shutdowns loomed in March 2020, a University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) team put the final plants in the ground, individual protective covers (IPCs) on trees, and kaolin and pesticide applications on a 2.7-acre planting at the Citrus Research and Education …
The size of fruit that should be sprayed, the spraying interval and ways to avoid copper phytotoxicity were among the citrus canker topics plant pathologist Megan Dewdney offered growers recently. Dewdney said fruit are most susceptible to canker when they are between 3/8 inch and 1.5 inches in diameter. The fruit rind becomes much more resistant when the fruit is …
The U.S. Department of Agriculture’s (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed the presence of citrus canker disease in a nursery in South Carolina. The nursery sells plants to consumers through online sales. Other nurseries did not receive these plants. Together with state partners, APHIS is working to collect and destroy the plants shipped to consumers in …
A new Hort Innovation project aims to shed some light on how black core rot happens in Australian groves so the citrus industry can learn how to better manage the disease. Black core rot caused by the fungus Alternaria spp. can be a problem for some citrus growers in the southern growing areas in Australia. Citrus infected with Alternaria spp. …
Citrus black spot (CBS) disease has only been found in five Southwest Florida counties, but that could change as a result of 2017’s Hurricane Irma, a researcher reiterated recently. University of Florida Institute of Food and Agricultural Sciences plant pathologist Megan Dewdney, in a Feb. 24 presentation, said “Irma will haunt us for a while.” She explained that Irma likely …
By Megan Dewdney Spring is around the corner, and Florida’s first wave of bloom is here. But there is no time to relax and enjoy the flowers because citrus diseases wait for no grower. Young fruitlets become susceptible to canker toward the end of March to the beginning of April. Missing that key window of protection — if the weather …
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 …
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 …
