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Below you'll find a list of all posts that have been categorized as “Diseases”
Agriculture officials announced the expansion of the sweet orange scab (SOS) quarantine and establishment of a new HLB quarantine area, both in California. SWEET ORANGE SCAB On March 11, the quarantine area for SOS in the Van Nuys area of Los Angeles County was expanded by 80 square miles. The U.S. Department of Agriculture Animal and Plant Health Inspection Service …
By Megan Dewdney It was a difficult winter for many citrus trees in Florida, with freeze damage and very dry weather stressing them. Trees will be flushing as much as they can to replace the damaged canopy lost over the winter. This means they will be drawing strongly on the bank of carbohydrates in the roots. The spring 2026 root …
Brazilian research organization Fundecitrus has for several years studied the use of kaolin for psyllids and the citrus greening they spread, as well as for citrus canker. Kaolin is a natural mineral composed mainly of aluminum silicate. In the kaolin experiments conducted by Fundecitrus, the commercial product Surround WP was used. PSYLLIDS AND GREENING The Fundecitrus studies show that spraying …
Florida citrus producers have long used copper as a way to protect against citrus canker. However, it’s time for growers to have other options. That’s a message shared by Ozgur Batuman, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) associate professor and citrus pathologist at the Southwest Florida Research and Education Center in Immokalee. He spoke on this …
Agriculture officials have expanded the areas quarantined for sweet orange scab (SOS) in the Los Angeles and Villa Park areas of Los Angeles and Orange counties in California. The U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) in cooperation with the California Department of Food and Agriculture (CDFA) expanded the quarantine. SOS is a disease caused by …
For the first time in Brazil, Fundecitrus has identified evidence of partial resistance of the fungus Phyllosticta citricarpa, which causes citrus black spot, to fungicides of the strobilurin group. This finding corroborates warnings issued by growers and technicians during the 2024–25 season regarding failures in controlling the disease in areas of the São Paulo Citrus Belt. SAMPLE STUDY A study …
Freeze damage to Florida citrus could lead to a buildup in certain diseases. One, in particular, is a major threat, believes Megan Dewdney, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) associate professor in plant pathology and Extension specialist. “Our big concern in terms of foliar problems is going to be melanose. Just as a reminder, melanose produces …
By Megan Dewdney The recent freeze events of the last few weeks have scrambled the plans of citrus growers. It will take several weeks to months to understand the extent of the damage caused by the unusually cold weather. MELANOSE There is at least one disease that is highly likely to be worse than in other years. Melanose is likely …
Agriculture officials have expanded the areas quarantined for citrus greening disease (known as huanglongbing or HLB) in California. The quarantined area in the Corona area of Riverside County was expanded by 37 square miles. The San Juan Capistrano quarantined area of Orange County was expanded by 18 square miles. The actions were taken by the U.S. Department of Agriculture Animal …
Several Fundecitrus researchers recently made presentations at the Brazilian Workshop on Plant Disease Epidemiology, held in Pirenópolis, Goiás. The scientists discussed studies on disease epidemics affecting agricultural crops and management strategies. CITRUS FLOWER ROT FORECASTING Geraldo Silva Junior addressed the citrus flower rot forecasting system — developed in partnership with Luiz de Queiroz College of Agriculture University of São Paulo(ESALQ/USP) …
The new Citrus Plant Protection Guide 2025-26 from Australia’s New South Wales Department of Primary Industries and Regional Development (NSW DPIRD) is available online. The seventh edition of the guide provides up-to-date information on all aspects of managing pests and diseases in citrus orchards and includes updates on NSW DPIRD projects. Some of the projects are funded by Hort Innovation …
Federal agriculture officials on Nov. 25 announced the expansions of the areas quarantined for sweet orange scab (SOS) and huanglongbing (HLB) diseases in California. The U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) in cooperation with the California Department of Food and Agriculture (CDFA) enacted the expansions. SOS The SOS quarantined area has been expanded by 5 …
Plant pathologist Megan Dewdney on Nov. 20 presented updates on greasy spot, greasy-green, citrus black spot (CBS) and phytophthora brown rot. Dewdney is a University of Florida Institute of Food and Agricultural Sciences associate professor and Extension specialist at the Citrus Research and Education Center. GREASY SPOT AND GREASY-GREEN Dewdney reported that control measures for greasy spot, caused by the …
The Florida Fruit & Vegetable Association (FFVA) recently provided comments to the Office of the United States Trade Representative as part of the annual review of foreign barriers to U.S. exports and investment. The FFVA letter noted injury to Florida citrus caused by low-priced imports from Mexico and the European Union’s use of scientifically unjustified, non-tariff trade barriers. Letter excerpts …
Citrus canker, a federal and state regulated plant disease, has been detected in Mobile County, Alabama. As required by federal law, the Alabama Department of Agriculture and Industries (ADAI) will establish a citrus canker quarantine for the county. The Auburn University Plant Pathology Lab confirmed the first detection from foliage and fruit samples collected during ADAI’s routine citrus survey. The …
Recent research has shown that systemic acquired resistance (SAR) sprays can protect young citrus tree flushes from Asian citrus psyllid (ACP) feeding, HLB and citrus canker. ACP is the vector that spreads HLB disease from tree to tree. Researchers with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) and Bayer Crop Science report that SAR sprays can …
The University of Georgia (UGA) has disease labs and clinics to help citrus producers determine what diseases are impacting their trees. Jonathan Oliver, UGA assistant professor and small fruits pathologist, highlights the diagnostic facilities that growers can take advantage of. “We have a lab in Tifton, the Plant Disease Clinic, that can accept samples from commercial citrus,” Oliver said. “We …
Federal and state officials recently expanded the area quarantined for citrus greening disease, also known as huanglongbing or HLB, in California. They expanded the quarantined area in the San Clemente area of Orange and San Diego counties by 81 square miles. The action was taken by the U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) in cooperation …
By Megan Dewdney Sometimes there is an unfortunate coincidence between the timing of fruit changing color and rain events. This can set up a situation where brown rot occurs unexpectedly and growers need to stop the disease after it has begun. CONTROL OPTIONS By this time of year, the traditional brown rot control measures are less effective. These are primarily …
Vulnerability of citrus trees to phytophthora root rot is a concern for cold-hardy growers. But there are precautions that producers can implement that will guard against infection buildup. One of those precautions includes site selection and not planting trees in poorly drained locations, according to Jonathan Oliver, University of Georgia assistant professor and small fruits pathologist. “Site prep is really …
