disease

Dealing With Disease: Canker, Black Spot and More

Daniel CooperDiseases

As the rainy season in Florida is set to begin, we caught up with Megan Dewdney to discuss citrus canker and other disease issues. Dewdney is a plant pathologist with the University of Florida Institute of Food and Agricultural Sciences. Q: How has the prevalence of citrus canker been in Florida in the past year or so? A: Dewdney: Citrus …

disease research

Citrus Disease Research Funding Applauded

Daniel CooperDiseases, Legislative

Three citrus grower associations applauded Chairman GT Thompson and the U.S. House Agriculture Committee for including critical funding for the Emergency Citrus Disease Research and Extension Program in the recent budget reconciliation draft. The associations were California Citrus Mutual (CCM), Florida Citrus Mutual (FCM) and Texas Citrus Mutual (TCM). The investment represents a vital commitment to the long-term health and …

Branch rot

Branch Rot Hits Brazilian Orchards

Daniel CooperBrazil, Diseases

The disease branch rot is worrying Brazilian citrus growers because of its recent increased occurrence in orchards. Branch rot is also called peduncular rot, branch gummosis or bot gummosis. The main reason for the disease’s occurrence is stress caused to citrus plants by high temperatures, severe periods of drought and attacks from other diseases, such as greening. Fungi of the …

Citrus canker

Reduce Fruit Drop From Citrus Canker

Daniel CooperDiseases, Fruit Drop, Tip of the Week

By Megan Dewdney Citrus canker can contribute significantly to the loss of fruit prior to harvest. As bloom begins in Florida, it is time to finalize management plans for foliar diseases. For many growers, very aggressive canker management programs are no longer a possibility, however, some management is important. Citrus canker susceptibility of young fruitlets usually starts at the end …

mathematical modeling

Mathematical Modeling Is Preparing Europe for HLB

Daniel CooperDiseases, International, Research

A tool predicting how to protect European citrus from HLB shows how mathematical modeling can help prepare for future plant disease invasions. Europe is currently unaffected by HLB. However, there are increased concerns of an infestation since psyllids that spread HLB have been found in key citrus-producing countries, including Portugal and Spain. In response to the HLB threat, a new …

disease

Florida Foliar Disease Outlook for 2025

Daniel CooperDiseases

By Megan Dewdney As I write this article in January 2025, the world is a chilly place, and it is hard to imagine warm and wet weather in Florida. The predicted weather pattern from now until flowering is moving from La Niña toward neutral. This is predicted to bring above-average spring temperatures with reduced rainfall. This is a hopeful sign …

Arizona

HLB Confirmed in Arizona for First Time

Daniel CooperDiseases, Regulation

HLB was recently confirmed for the first time in Arizona, first in an Asian citrus psyllid (ACP) and then in another ACP and citrus plant tissue. The Arizona Department of Agriculture (AZDA) reported the details. On Dec. 16, 2024, agriculture inspectors collected ACP and plant tissue samples from a residential citrus tree in Nogales. The collections were made during a …

Mississippi

Quarantine Updates: HLB in Mississippi; Mexfly in Texas

Daniel CooperDiseases, Pests, Regulation

The U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA/APHIS) recently announced a quarantine for huanglongbing (HLB) in Mississippi as well as updates to Mexican fruit fly (Mexfly) quarantines in Texas. HLB APHIS, in cooperation with the Mississippi Department of Agriculture and Commerce, established a quarantine for the entire state of Mississippi for HLB. The action was taken …

virus

Stay Vigilant About Virus Threat

Daniel CooperDiseases, Tip of the Week

By Ozgur Batuman and Amit Levy Citrus yellow vein clearing virus (CYVCV) was first reported on lemon and sour orange trees in Pakistan in 1988. Since then, the disease has been primarily restricted to Asian countries. However, CYVCV was more recently detected in dooryard citrus in California in 2022. While there is no indication that the virus is present in …

march

Sneak Peek: March 2025 Citrus Industry

Daniel CooperDiseases, Sneak Peek, Soil Health

The Citrus Industry section in the March issue of Specialty Crop Grower magazine offers timely information citrus growers won’t want to miss. Now is the time for Florida citrus producers to begin thinking about their disease management programs for the season. Megan Dewdney, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) plant pathologist, offers a foliar disease outlook …

weather

Foliar Disease Watch in Florida

Daniel CooperDiseases, Tip of the Week

By Megan Dewdney Spring is the time to start thinking about foliar disease management in Florida. Depending on the type of citrus being produced and the market destination, different diseases will be important. POSTBLOOM FRUIT DROP The disease that affects all citrus, particularly oranges, is postbloom fruit drop (PFD). This disease is highly dependent on the weather during bloom. Currently, …

usda

USDA Funds Citrus Projects

Daniel CooperDiseases, Pests, Research

The U.S. Department of Agriculture (USDA) announced an investment of more than $70 million in the Plant Protection Act program. This includes funding of 357 projects in fiscal year 2025. The work will strengthen the country’s defenses against plant pests and diseases, safeguard the U.S. nursery system, and enhance pest detection and mitigation efforts. Part of the funding is going …

Protect Trees Post-Freeze With Fungicide

Tacy CalliesCold Hardy, Diseases, freeze

Growers in the cold-hardy citrus region should consider fungicide application following snow last week and multiple days of running irrigation for freeze irrigation. That advice comes from Lindy Savelle, executive director of the Georgia Citrus Association, on the heels of historic snowfall recorded across the Southeast. “I’ve heard some people having up to 10 inches of snow where we grow …

Sweet Orange Scab

Sweet Orange Scab Quarantined Area Expanded

Daniel CooperCalifornia Corner, Diseases, Regulation

Effective immediately, the U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS), in cooperation with the California Department of Food and Agriculture (CDFA), is expanding the sweet orange scab quarantine in the Santa Ana area of Orange County in California. APHIS is expanding this quarantined area by 32 square miles because of a sweet orange scab detection in …

research center

Research Center to Combat Brazilian Citrus Diseases

Daniel CooperBrazil, Diseases, Research

The Applied Research Center for Innovation and Sustainability in Citrus Farming was inaugurated Dec. 12 in a ceremony at the Palácio dos Bandeirantes, seat of Brazil’s São Paulo state government. Its purpose is to combat the main citrus diseases, such as citrus variegated chlorosis, sudden citrus death and above all, citrus greening. The São Paulo Research Foundation (FAPESP), Fundecitrus and …

expanded

HLB Quarantine Expanded in California

Daniel CooperCalifornia Corner, Diseases, Regulation

An area quarantined for huanglongbing (HLB), also known as citrus greening disease, in California was recently expanded. The U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) in cooperation with the California Department of Food and Agriculture (CDFA) issued the expansion. The quarantined area in the Mission Viejo area of Orange County expanded by approximately 85 square miles. …

diseases

Problematic Diseases Following Hurricanes

Daniel CooperDiseases, hurricane

Hurricanes bring immediate tree damage from high winds and torrential rainfall, but storms also can lay the groundwork for citrus disease problems. Soon after Hurricane Milton passed through citrus-growing regions, the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) hosted a webinar that covered various topics including post-storm disease management. CANKER Megan Dewdney, UF/IFAS associate professor of plant …

citrus canker

Citrus Canker Spreading in Cold-Hardy Region

Daniel CooperCold Hardy, Diseases

Citrus canker has long been a presence and concern for Florida’s citrus growers. Growers in North Florida, South Georgia and South Alabama should be wary of its potential spread into the cold-hardy citrus region. Clive Bock, a research plant pathologist with the U.S. Department of Agriculture, spoke about the disease during the recent Cold-Hardy Citrus Meeting at the University of …