University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) multi-county citrus Extension agent Ajia Paolillo discussed brown rot management in the September Extension newsletter, Citrus from the Ridge to the Valley. Her article follows. As we move into September, it is essential to remember that brown rot can impact yield, especially early varieties. Brown rot is caused by either …
Canker Eradication Efforts Underway in Texas
The Asiatic A strain of citrus canker was recently found in the Upper Gulf Coast area of Texas, posing a significant threat to the state’s commercial citrus production. The U.S. Department of Agriculture (USDA), the Texas Department of Agriculture and the Texas A&M University-Kingsville Citrus Center are collaborating on surveys to detect the disease. They are also removing and properly …
All In For Citrus Podcast, August 2021
This month’s All In For Citrus Podcast gives growers valuable advice for dealing with hurricanes and tropical storms. The University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) team describes how to prepare for and recover from these weather events, as well as the impacts they can have on Florida’s economy. Before getting to the information about storms, the …
Controlling Diplodia Stem-End Rot Before Harvest
By Mark A. Ritenour, Jiuxu Zhang, Liliana M. Cano and Megan M. Dewdney The decay of fresh citrus fruit in Florida is usually caused by fungal pathogens that grow and develop in the hot and wet conditions typical to the state. While green and sometimes blue Penicillium molds and sour rot can cause Florida fruit to decay, the subtropical conditions …
Expo Focus: ‘What Growers Can Do Now’
Many of the citrus presentations featured on the first day of Citrus Expo, Aug. 18, will focus on “what growers can do now” to keep groves productive, Michael Rogers reports. Rogers, director of the University of Florida Institute of Food and Agricultural Sciences’ (UF/IFAS) Citrus Research and Education Center, offers what he calls “a 30,000-foot view” of the citrus seminar …
Time for Brown Rot Management
By Evan Johnson The Florida summer rainy season is in full swing, and there have been one or two root flushes by now. This is a good environment for increases in soil Phytophthora propagule counts. High counts have been seen this year, especially in Southwest Florida. While much of the focus may be on root rot, it is important to …
Unlocking the Citrus Microbiome
Yunzheng Zhang, Nian Wang and colleagues recently published an article, The Citrus Microbiome: From Structure and Function to Microbiome Engineering and Beyond, in the Phytobiomes Journal. It outlines the structure and potential functions of the plant microbiome. It explains how this knowledge can lead to new engineering feats and a greater understanding of the plant microbiome. Insights into the microbiome …
Technology for Early HLB Diagnosis
Penn State and U.S. Department of Agriculture (USDA) scientists have used cutting-edge CRISPR/Cas technology to develop a diagnostic test that could enable early diagnosis of huanglongbing (HLB). In a study newly published in the journal Phytopathology, the researchers demonstrated that the new test can detect the presence of the HLB causal agent — the bacterium Candidatus Liberibacter asiaticus (CLas) — …
HLB, Lemons and Oranges
A group of scientists working in California, New York and Washington has found that Lisbon lemon trees had less of a molecular response than Washington navel orange trees to the pathogen that causes HLB. That pathogen is Candidatus Liberibacter asiaticus (CLas). In part, this might be because leaves of infected lemons tended to accumulate micronutrients, which led to less of …
HLB Slowed by Biocontrol
Florida citrus growers may have a new tool to help them slow the presence of HLB in already diseased trees, courtesy of researchers at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS). The researchers found that injecting a benign Xylella fastidiosa EB92-1 bacteria biocontrol into infected citrus trees over a period of six years reduced the incidence …
Research ‘of Use to Growers Right Now’
“We’ve come a long way in the time that we’ve had HLB here in Florida,” says Michael Rogers. The director of the University of Florida Institute of Food and Agricultural Sciences’ (UF/IFAS) Citrus Research and Education Center says early HLB research “covered a wide range of topics.” Now, however, “We’re really narrowing down things that are of use to growers …
Time to Check Under the Hood for Nematodes
By Larry Duncan Monitoring population levels of plant parasitic nematodes and phytophthora is best done in springtime prior to the rainy season. Peak population density of the citrus nematode (Tylenchulus semipentrans) occurs at that time, and the accuracy of sample results increases with population density. The sampled population levels of this nematode and those of Phytophthora spp. can be compared …
Improving Root Health in the Era of HLB
Developing and maintaining a healthy root system is crucial for establishment and long-term productivity of citrus trees. The presence of HLB can greatly complicate citrus root-health management. The infection causes severe damage to fibrous roots that amplify the detrimental effects caused by other root pests and pathogens, such as phytophthora root rot. Due to HLB’s widespread presence throughout Florida, root-health …
Canker Treatment Uses Less Water and Copper
An important bacterial disease that affects citrus trees and causes lesions, citrus canker has been effectively controlled by spraying copper. However, standard management techniques involve spraying excessive amounts of copper and water without consideration for the size of the trees. “This technique resulted in a waste of resources as well as higher costs, detrimental environmental impact and risk for development …
App Now Available to Diagnose Citrus Leaf Problems
Visual identification of nutrient deficiencies and leaf damage is an important diagnostic tool for fine-tuning management of citrus. Arnold Schumann, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) professor, shared how UF/IFAS researchers have used artificial intelligence (AI) to diagnose citrus nutritional deficiencies, diseases and pest damage. According to Schumann, disease and pest symptoms on leaves may cause …
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 …
HLB: The Microbiome’s Role
Researchers Caroline Roper and Nichole Ginnan at the University of California, Riverside led a large research collaboration that sought to explore the microbiome’s role in HLB disease progression. Their recent article in Phytobiomes Journal, “Disease-Induced Microbial Shifts in Citrus Indicate Microbiome-Derived Responses to Huanglongbing,” moves beyond the single-snapshot view of the microbial landscape typical of microbiome research. Their holistic approach …
Peptide, CRAFT Research Funded
A company that recently obtained a patent for a natural peptide solution to treat HLB has received Citrus Research and Development Foundation (CRDF) funding to see if the product has efficacy for other citrus diseases. CRDF will fund the company, Elemental Enzymes, for about $61,200, said CRDF Chief Operating Officer Rick Dantzler. Elemental Enzymes proposes to do research “to see …
Emerging Trunk Disorders
By Evan Johnson and Megan Dewdney The last two years have seen increasing grower questions and reports of citrus trunk disorders in Florida. Sometimes these reports are associated with sudden tree collapse. In many cases, phytophthora foot rot is initially suspected. Typically, the symptoms don’t quite match those of foot rot, and phytophthora cannot be isolated from the lesion. If …
Using CRISPR for HLB Resistance
Use of CRISPR (clustered regularly interspaced short palindromic repeats) technology has already produced trees that are highly resistant to citrus canker. In a Citrus Expo virtual presentation, microbiology and cell scientist Nian Wang reported on work that is being done with CRISPR to develop tree resistance to HLB. Wang is a University of Florida Institute of Food and Agricultural Sciences …