Phosphite Best for Algal Spot

Ernie Neff Diseases

Algal spot had rarely been seen in Florida groves until fairly recently, Megan Dewdney reported in a virtual Florida Citrus Growers’ Institute presentation. The University of Florida Institute of Food and Agricultural Sciences plant pathologist said she started hearing from concerned orange growers within the past five years. Those growers told her that copper, the historical recommendation for the disease, …

Viroid Found on Georgia Citrus

Ernie Neff Diseases

Hop stunt viroid (HSVd) was found on citrus in Georgia for the first time this year. University of Georgia Cooperative Extension warns that HSVd and other viroids could pose a threat to the state’s growing citrus industry in susceptible varieties. Leaf samples were collected in May and June from 12 different citrus plants in two nurseries in southern Georgia. Nine …

Black Spot and Production Guide Updates

Ernie Neff Diseases

Megan Dewdney recently provided information about positive results from fungicide trials for citrus black spot, as well changes to the new Citrus Production Guide. Dewdney is a plant pathologist with the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), working at the Citrus Research and Education Center. Dewdney conducted the fungicide trials for black spot in a 20-year-old …

Phytophthora Root Rot Management

Tacy Callies Diseases, Tip of the Week

By Evan G. Johnson As September winds down, the fall root flush is starting and will continue through November/December. This is the largest root flush of the year that stores carbohydrate reserves for next spring. Coming out of the rainy season, phytophthora has had the chance to build up plenty of inoculum, especially in groves with a history of root …

Citrus Disease: What to Watch for in Georgia

Tacy Callies Diseases

The citrus greening disease (huanglongbing or HLB) that has devastated Florida’s citrus industry over the past decade has not affected Georgia commercial production. However, growers should still be aware of the potential danger it can bring. According to Jonathan Oliver, fruit pathologist and Extension specialist in the Department of Plant Pathology at the University of Georgia (UGA), all confirmed HLB-positive …

APHIS Annual Report Highlights Citrus Efforts

Tacy Callies Diseases, Pests

The U.S. Department of Agriculture Animal and Plant Health Inspection Service (APHIS) recently released an annual report titled “Plant Protection and Quarantine: Helping U.S. Agriculture Thrive — Across the Country and Around the World.” The document includes updates on efforts to manage citrus diseases. “PPQ (Plant Protection and Quarantine) stands shoulder-to-shoulder with citrus growers to combat citrus canker, huanglongbing (HLB …

Canker Quarantine Expanded in Texas

Clint Thompson Citrus, Diseases, Florida, Top

The U.S. Department of Agriculture’s Animal and Plant Health Inspection Service (APHIS) announced June 30 it was immediately expanding the area quarantined for citrus canker in Texas. The agency added portions of Cameron County near San Benito and Brownsville to prevent the spread of the disease. APHIS confirmed the positive identification of citrus canker in two residential trees in San …

Nursery Diseases at Planting: What to Watch for

Tacy Callies Diseases, nursery

By Ozgur Batuman and Megan Dewdney Citrus nurseries work very hard and put forth considerable effort to reduce pest and disease problems. However, there continues to be problems with certain diseases, because the nursery environment for growing citrus trees is ideal for many pests and diseases. Basic principles of good nursery sanitation practices together with screening and removing suspected or …

Citrus Canker Management Through the Year

Ernie Neff Diseases

Plant pathologist Megan Dewdney with the University of Florida Institute of Food and Agricultural Sciences offers suggestions for managing citrus canker at different times of the year. She is an associate professor at the Citrus Research and Education Center (CREC) in Lake Alfred. Dewdney suggests that copper sprays begin when fruit reach three-eighths of an inch in diameter in groves …

Algal Spot: A Re-emerging Disease

Tacy Callies Diseases

By Megan M. Dewdney Algal spot has not been seen frequently for many years, but in the last few years I have been getting more questions about identification and management. The disease is caused by a green alga, Cephaleuros virescens. The alga is not considered a parasite, as it grows superficially, but it does cause damage to trees if left …

Citrus Leprosis Poses a Threat to Florida

Tacy Callies Diseases

By Amit Levy, Ozgur Batuman, Peggy Sieburth and Lauren Diepenbrock Citrus leprosis is an exotic viral disease not currently present in Florida. This disease is of interest since it was reported in citrus in Florida and Brazil in the early 1900s, where it caused great crop and tree losses, but it was eliminated from Florida in the early 1960s. Currently, …

Planning for Foliar Disease Management in 2020

Tacy Callies Diseases

By Megan Dewdney and Evan Johnson In 2019, the trend of fewer problems with foliar fungal diseases for Florida citrus continued, which was good news for the industry. Despite the El Niño conditions during the spring, little postbloom fruit drop (PFD) was observed because the temperatures were low (< 75 F) when it rained during bloom. The southern parts of …

budget

Homeowners Oppose Stay in Citrus Tree Battle

Daniel Cooper Diseases, Legislative

(NSF) — Attorneys for Lee County homeowners urged the Florida Supreme Court on Monday to reject the state’s request for a stay in a long-running legal battle about compensating residents for healthy citrus trees cut down amid an effort to halt the spread of citrus canker disease. The Florida Department of Agriculture and Consumer Services last week asked the Supreme Court to put the …

aphis

Citrus Black Spot Quarantine Area Updated in Florida

Daniel Cooper Diseases, Industry News Release

Effective immediately, the Animal and Plant Health Inspection Service (APHIS) is adding eight sections in Charlotte County, nine sections in Lee County, 28 sections in Hendry County, and five sections in Collier County to the citrus black spot (CBS) quarantine area in Florida. This action is in response to the confirmation of CBS during annual surveys conducted by APHIS and …

orange juice

FDOC Response to Cancer Study

Daniel Cooper Citrus, Diseases, Industry News Release, Research

A new study suggesting a link between sugary drink consumption, including 100% fruit juice, and increased cancer risk was recently published in a medical journal. The study has spurred a series of news media stories. Researchers of the study, who are based in France, assessed the associations between the consumption of sugary drinks (sugar sweetened beverages and 100% fruit juices), …

citrus greening

Studying Citrus Greening with an Integrated Approach

Daniel Cooper Citrus Greening, Diseases, HLB Management, Industry News Release, Psyllids, Research

While citrus growers continue to look for best management approaches to deal with the deadly greening disease, scientists will take an integrated look at how to protect young trees by using existing tools growers can use. Five scientists from the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) will compare insect management tools, including insect-proof netting. Researchers also …

An Important Reminder on Citrus Tristeza Virus

Tacy Callies Diseases

By Amit Levy and Ozgur Batuman Citrus tristeza virus (CTV) is an important citrus pathogen that, in the past, had a dramatic effect on the citrus industry and caused the loss of almost 100 million trees worldwide. These trees were propagated on sour orange rootstock. The disease created a need for tristeza-tolerant rootstocks to sustain the citrus industry, because only …

Citrus Black Spot Update

Ernie Neff black spot, Diseases

Callie Walker with the Florida Department of Agriculture and Consumer Services (FDACS) recently gave an update on the citrus black spot quarantine in Southwest Florida. Walker is bureau chief of pest eradication and control for FDACS’ Division of Plant Industry and serves as statewide director for the Citrus Health Response Program. She summarizes the presentation she made at the Florida …

aphis

Hurricane Irma Raises Black Spot Threat

Ernie Neff black spot, Diseases

University of Florida Institute of Food and Agricultural Sciences Extension pathologist and associate professor Megan Dewdney reported that U.S. Department of Agriculture (USDA) scientist Tim Gottwald thinks there’s a “fairly high” chance that Hurricane Irma spread citrus black spot. Black spot had been confined primarily to Southwest Florida, especially Collier and Hendry counties, before Irma hit the state with damaging …

Phytophthora: An Old Problem with New Challenges

Tacy Callies Diseases

By Evan Johnson Diseases caused by phytophthora continually threaten Florida citrus production. Brown rot can directly reduce yields of early maturing varieties including Hamlin and grapefruit, can delay harvest of fresh market fruit until infected fruit have dropped, or risk packinghouse rejection of the load because it can spread post-harvest. Foot and crown rot can kill trees but are uncommon …