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Below you'll find a list of all posts that have been categorized as “Diseases”
California Department of Food and Agriculture (CDFA) and U.S. Department of Agriculture (USDA) officials have confirmed the detection of HLB in one tree in a residential property in the city of Calexico, Imperial County, California. This is the first HLB detection in a tree in Imperial County. In November 2025, an Asian citrus psyllid (ACP) was confirmed positive in Imperial …
Although huanglongbing (HLB) disease was highlighted in the citrus section of the U.S. Department of Agriculture Animal and Plant Health Inspection Service’s (USDA APHIS) recent PPQ (Plant Protection and Quarantine) 2025 Annual Report, the report also noted efforts against other citrus diseases. Those diseases include citrus canker, citrus yellow vein clearing virus, sweet orange scab and citrus black spot. The …
A recent article from Alabama A&M and Auburn universities highlighted the major issues facing citrus growers in southern Alabama’s Baldwin and Mobile counties. FREEZES One of the biggest obstacles that citrus growers face is highly variable weather, including late-season freezes. Jacob Kelley, an Alabama Extension commercial horticulture agent at Auburn University, said winter temperatures that might swing from 80 to …
Federal and state agriculture officials have taken actions regarding Mediterranean fruit fly (Medfly) and sweet orange scab (SOS) quarantines 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) updated the quarantines. MEDFLY QUARANTINE REMOVED The agencies removed the Medfly quarantine in Alameda and Santa …
The U.S. Department of Agriculture Animal and Plant Health Inspection Service and the California Department of Food and Agriculture (CDFA) confirmed the positive identification of citrus yellow vein clearing virus (CYVCV) in a residential citrus tree in the Lodi area of San Joaquin County. The plant sample was confirmed positive for CYVCV on July 7 following a routine multi-pest survey …
In Florida, the soilborne phytophthora pathogens — primarily Phytophthora nicotianae and Phytophthora palmivora — are the leading causes of root rot, crown rot and foot rot. Two University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers recently wrote about phytophthora management in cold-hardy citrus. The authors are Assistant Professor and Extension Specialist Muhammad Shahid and postdoc Carlos Aucique-Perez, …
Postharvest diseases such as green mold (Penicillium digitatum), blue mold (P. italicum) and sour rot (Geotrichum citri-aurantii) cause heavy losses in citrus crops. These fungi thrive in warm, humid regions and have developed resistance to common fungicides such as imazalil, thiabendazole and pyrimethanil, driving up costs and raising environmental and regulatory concerns. A new study offers hope using a simple, …
A new study has identified several fungal pathogens associated with preharvest sweet orange fruit spoilage. It provides insights that could help citrus growers better understand and manage fruit rot problems in the grove. The research, “Morphological Identification of Fungi Associated with Preharvest Spoilage of Sweet Orange (Citrus sinensis L.) Fruit in Bilo Nopha, Southwestern Ethiopia,” was published in the journal …
Southeastern residents increasingly support stronger protections against agricultural disease threats as concerns grow over food-system disruptions, say researchers at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS). Findings from an August 2025 public interest survey distributed to 1,035 Southeast residents reflect growing public concern about how agricultural threats can affect food systems, public health and disaster preparedness. …
By Lauren Fessler Mathews, Ana Redondo and Ozgur Batuman Citrus canker continues to impact Florida citrus, increasing premature fruit drop and decreasing yield and fruit quality. While copper sprays have long been relied upon to control this disease, concerns about environmental impact and possible resistance development have led to efforts to find sustainable alternatives. Previous studies have shown that plant …
The U.S. Environmental Protection Agency (EPA) released its draft Fungicide Strategy and is inviting the public to weigh in. The draft strategy identifies practical, science-based protections that fungicide users can adopt to safeguard more than 1,000 federally endangered and threatened species. The strategy also aims to preserve the flexibility that states, growers and applicators need. EPA is opening this draft …
The U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) in cooperation with the California Department of Food and Agriculture (CDFA) have expanded the area quarantined for sweet orange scab (SOS). The expansion is in the Irvine area of Orange County and in the La Puente area of Los Angeles County in California. QUARANTINE ACTIONS APHIS is expanding …
By Megan Dewdney Algal spot is rarely a top concern for growers until it seems to be suddenly everywhere. Is the disease a major concern or a nuisance? It depends. If the disease is only in a few locations, then the management goal is making sure that the disease is not spreading too widely. If many trees are affected, the …
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 …
