“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 …
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 …
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 …
Weird Trunk Disorders in Groves
Florida growers, Extension agents and others have been baffled by unusual trunk symptoms during what Evan Johnson termed “the year of the weird trunk disorder.” Growers spotted the disorders, which were similar to phytophthora, in groves over the past one and half to two years. Johnson addressed three of the disorders, which have been found in multiple counties. Johnson, a …
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 …
Rootstock Offers High Hopes for HLB Tolerance, Maybe Resistance
The new Sugar Belle hybrid rootstock LB8-9xS13#16 has quite a history, according to University of Florida Institute of Food and Agricultural Sciences citrus breeder Jude Grosser. “This is one of several projects I did with Orie Lee toward the end of his Florida Citrus Hall of Fame career/life,” recalls Grosser. “We did a lot of brainstorming together, and he was …
New Rootstocks in the Citrus Breeding Pipeline
By Jude Grosser, Fred Gmitter and Kim Bowman Two citrus breeding programs have identified several rootstocks that can currently be planted with confidence when combined with appropriate scions, including mid- and late-season oranges, and grown with emerging enhanced nutrition programs. These citrus breeding programs are at the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Research and Education …
Rootstock Effects on Valencia and Hamlin in Large-Scale Commercial Plantings
By Ute Albrecht, Sudip Kunwar and Jude Grosser Prior to 1865, the only rootstocks used in Florida were sour orange and sweet orange. Use of grafted trees instead of seedling trees became necessary because of the devastating effects of phytophthora on sweet orange. Sour orange was widely used as a rootstock because of its resistance to phytophthora and other positive …
How to Use the New Florida Citrus Rootstock Selection Guide
By Rhuanito S. Ferrarezi, William S. Castle, Kim D. Bowman, Jude W. Grosser, Stephen H. Futch, Steve Rogers and Andres Gonzalez First published in 1989 as Rootstocks for Florida Citrus, the work of William Castle and his colleagues remains relevant 30 years later. The purpose of the fourth edition of the Florida Citrus Rootstock Selection Guide is to provide timely …
Smartphone App Under Development for Diagnosing Citrus Leaf Symptoms
By Arnold Schumann, Perseverança Mungofa, Laura Waldo and Chris Oswalt Since the first Apple iPhone was launched in 2007, there have been many improvements to smartphone cameras and their increasingly powerful graphics-processing capabilities. In recent years, these powerful hand-held computers have also made their impact on agriculture, where they are being used for communications, mapping, navigation, information retrieval and diagnostic …
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 …
Even in Times of Crisis, Citrus Research Continues
(UF/IFAS) —The coronavirus has upended daily routines, events and schedules. From work to schools to shopping, every aspect of life changed overnight and continues to change with each passing day. Even with a global pandemic, University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) citrus researchers plow forward in their quest to find answers to fighting the devastating disease …
Root Health Update
Evan Johnson, a University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) plant pathologist at the Citrus Research and Education Center, updates efforts to help citrus tree roots cope with HLB. He starts by noting that around 10 years ago he and former UF/IFAS researcher Jim Graham discovered “that HLB causes severe damage to the root system.” They hoped …
Newly Planted Trees and HLB
Newly planted trees need to have root systems that are as established, robust and healthy as possible before contracting HLB, Evan Johnson told growers at Citrus Expo. That’s because HLB takes out a tree’s fibrous root system and causes dieback of the structural root system. Having strong root systems from the start will increase the productive life of trees, the …
Optimize Fresh Fruit Results With Selective Pruning
By Christopher Vincent and Mark Ritenour Planting fresh citrus varieties has increased in popularity. With these potentially high-value crops come questions about management practices, including pruning. This article discusses pruning practices that can improve the health and productivity of citrus trees. The principles of pruning are the same for any citrus plant. However, quality affects value of fresh fruit even …
Israel’s Dynamic Citrus Industry
By Stephen H. Futch and Ariel Singerman As home to three of the world’s major religions, Israel is one of the most diverse countries in the world. Besides its cultural diversity and historical importance, Israel is also a major citrus producer and exporter. Israel’s citrus industry began in 1882. As new immigrants moved to the country, they established many very …