“When a tree gets infected, there is generally no way to cure it,” University of Maryland virologist Anne Simon wrote in a recent white paper about invasive tree diseases. She explained that trees lack adaptive immune systems, so once infected they typically must tolerate the pathogen for the remainder of their lifespan. “In some cases, immunity can be provided by …
Fungal Disease Management Recommendations
University of Florida multi-county citrus Extension agent Chris Oswalt discussed fungal disease management in the April Central Florida citrus Extension newsletter. Here is a summary: In Florida, fruit fungal diseases that are oftentimes problematic in the early spring are melanose, scab and alternaria brown spot, along with citrus canker. In the summer period, greasy spot is more of a problem, …
Stem Pitting Disease Caused by Citrus Tristeza Virus
By Amit Levy, Peggy Sieburth and Ozgur Batuman When we hear or read about citrus tristeza virus (CTV), we usually think about the decline of sweet orange or grapefruit trees on sour orange rootstocks. However, there are other diseases caused by different isolates of the virus. One of these diseases is stem pitting, mostly caused by the VT isolate of …
Foliar Disease Management in 2021
By Megan Dewdney There were many challenges in 2020, but fortunately the Florida season for foliar citrus diseases was relatively normal. Little to no postbloom fruit drop (PFD) was reported during the 2020 bloom because of a sudden dry spell as the flowers opened. As spring 2021 approaches, the forecast is for a La Niña weather pattern with slightly warmer …
Citrus Diseases to Pay Attention to
Phytophthora and leprosis diseases can each substantially reduce productivity of a citrus tree, but when they attack trees already weakened by HLB, the result can be fatal. Ozgur Batuman, assistant professor at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS), explained how co-infection impacts HLB-infected trees during a recent UF/IFAS webinar. PHYTOPHTHORA DISEASESPhytophthora species are soil-borne fungal pathogens …
Georgia Citrus Pest and Disease Update
As the Georgia citrus industry continues to grow and prosper, growers should be aware of the potential signs of citrus pests and diseases that could be looming in their groves. Bill Barber, Certified Crop Advisor and owner of Barber Ag Services, delivered a presentation during the 2021 virtual Southeast Regional Fruit and Vegetable Conference. He addressed pests and diseases presently …
Citrus Disease: What to Watch for in Georgia
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 …
Nursery Diseases at Planting: What to Watch for
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 …
Algal Spot: A Re-emerging Disease
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 …
Planning for Foliar Disease Management in 2020
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 …
California Citrus Pest & Disease Prevention Program Report Released
The California Department of Food and Agriculture (CDFA) released the 2018 annual report from the Citrus Pest & Disease Prevention Program (CPDPP). According to the report, California citrus is a $3.3 billion industry, providing 21,600 jobs and covering 268,500 acres. HLB (huanglongbing, also known as citrus greening disease) is the leading threat in citrus today. In 2018, HLB was found …
Fungal Foliar Disease Concerns for 2019
By Megan Dewdney The Florida citrus-growing seasons of 2017 and 2018 were quiet in terms of fungal foliar disease outbreaks. Small pockets of severe disease occurred sporadically, but there were no widespread reports of diseases like postbloom fruit drop, much to the relief of the industry. Greasy spot has flared up in a few locations on cultivars like Valencia, and …
UF/IFAS Researchers Search for Solutions to Citrus Diseases with Citrus Initiative Funds
From nutritional supplements to managing irrigation to grower outreach and education, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers are finding additional ways to support Florida citrus growers in their fight against citrus greening disease. Twelve projects were funded by the state legislature-funded Citrus Initiative program in 2017-2018 that looked at possible short- and long-term solutions that …
Artificial Intelligence for Detecting Citrus Pests, Diseases and Disorders
By Arnold Schumann, Laura Waldo, William Holmes, Gary Test and Tim Ebert Artificial intelligence (AI) is increasingly common in electronic devices at home or work, in social media, video streaming services, electronic commerce, and in internet search engines. Now, AI is rapidly entering the farming scene. Growers using modern precision agriculture tools and techniques often face a barrage of high …
University of California Scientists Identify New Citrus Disease
A new disease of citrus has been found in the Central Valley of California. According to a report published in the University of California’s (UC) Topics in Subtropics newsletter, several growers and nurserymen in various orchards in the Central Valley first noticed the disease in 2013. Symptoms include leaf chlorosis, crown thinning, gumming, dieback, and in severe cases, death of …
Living with Yellow Dragon Disease
A grower nutrition survey reveals production practices for successful HLB management. By Tripti Vashisth and Christopher Vincent These days, in nearly every conversation about HLB, mineral nutrition comes up in some way. It seems that in a conversation between three people, there will be about four opinions on what, why, where and how to provide nutrition to citrus trees in …
Robots May Soon Detect Grove Pests and Diseases
It may not be long before a grower sips coffee and works on the computer while a robot roams the grove checking for HLB-spreading psyllids and other pests and diseases. That’s thanks to machine vision software. University of Florida Institute of Food and Agricultural Sciences scientist Arnold Schumann tells about research he has been conducting. Schumann says researchers have developed …
USDA Invests in Fighting Citrus Greening Disease
The U.S. Department of Agriculture’s (USDA) National Institute of Food and Agriculture (NIFA) announced awards to combat citrus greening disease. The funding to support research and Extension programs is made through the emergency Citrus Disease Research and Extension Program (CDRE). CDRE was authorized as part of the 2014 Farm Bill. “The need to advance research and Extension to develop management …
Managing Disease with Copper and IPM
Integrated pest management (IPM) strategies and copper are both good control measures for common citrus foliar fungal diseases, as well as for citrus canker. So says University of Florida Institute of Food and Agricultural Sciences plant pathologist Ozgur Batuman. Batuman summarizes information he presented at a fall field day and seminar attended by about 60 people at the Southwest Florida …
Citrus Diseases Discussed at Farm Bill Listening Session
Various comments on many areas of agriculture were given during the first farm bill listening session hosted by the House Agriculture Committee recently in Gainesville, Florida. Among those who shared comments was John Barben, a fifth-generation citrus grower from Highlands County. He talked to committee members about citrus diseases. Hear his comments. Sponsored Content5 Facts About Fire Ants and …