Lessons Learned From HLB as an Immune-Mediated Plant Disease

Josh McGill HLB Management, Research

By Nian Wang How the huanglongbing (HLB) pathogen Candidatus Liberibacter asiaticus (CLas) causes damage to infected citrus trees has been widely debated. A recent study demonstrates that HLB is an immune-mediated plant disease (Ma et al., 2022). It was discovered that CLas infection of citrus stimulates systemic and chronic immune response in phloem tissues, including reactive oxygen species (ROS) production, …

Deficit Irrigation in HLB-affected Citrus Trees

Josh McGill Irrigation, Research

By Davie Kadyampakeni, Samuel Kwakye, Hossein Ghoveisi, Lauren Diepenbrock and Jawwad Qureshi Deficit irrigation practices can reduce water and energy costs, thus potentially increasing water-use efficiency and water savings in citrus production. Irrigation management through deficit applications, if timed at periods of reduced water demand, could help trigger increased root water and nutrient uptake while synchronizing citrus flush patterns. These …

Uruguay Has First HLB Detections

Josh McGill HLB Management, International

The first cases of plants with HLB disease have been confirmed in Uruguay, according to a health emergency note released by the country’s Ministry of Livestock, Agriculture and Fisheries. Plants with symptoms were found in a residence in the city of Bella Unión. After laboratory analysis, the presence of the disease was confirmed. Inspections were carried out in the homes …

CRDF Funds Project to Arrest HLB Bacteria

Josh McGill CRDF, Research

At the latest Citrus Research and Development Foundation (CRDF) board of directors meeting, funding was approved for a project by Robert Turgeon. He is a professor of plant biology at Cornell University. “Dr. Turgeon is considered by some to be the world’s foremost expert on phloem physiology. If his project succeeds, it could solve our problem with HLB,” CRDF chief …

HLB Concerns Government Officials in Brazil

Josh McGill Brazil, HLB Management

Brazil’s Fundecitrus on Feb. 15 participated in a meeting with state and local government representatives to discuss the country’s citrus greening (HLB) situation. Representatives of the Department of Agriculture and Supply (SAA) of the state of São Paulo and mayors of some municipalities in the citrus belt also attended. Mayors and representatives of city halls expressed concern about the economic …

areas

Why There Is a Lack of HLB in Georgia

Josh McGill Georgia, HLB Management

HLB has yet to become a major problem for Georgia’s citrus producers. Jonathan Oliver, University of Georgia assistant professor and small fruits pathologist, attributes the disease’s lack of presence in Georgia’s commercial groves to multiple factors. “It still comes down to the fact that, number one, you don’t see symptoms for a while. A lot of our trees are young,” …

Rectify Injection Available for HLB in Florida

Josh McGill HLB Management, Industry News Release, Pesticides

Rectify, AgroSource, Inc.’s 95% oxytetracycline hydrochloride-based tree-injection product, is expected to be available for use against HLB in Florida citrus as early as Feb. 24. The product will be available to growers through existing commercial agricultural product distributors. AgroSource petitioned and received a Special Local Needs (SLN) approval for Rectify by the Florida Department of Agriculture and Consumer Services (FDACS) …

First HLB Confirmation in City of San Diego

Josh McGill California Corner, HLB Management, Regulation

The citrus disease HLB has been confirmed for the first time in the city of San Diego, California, making it the second city in San Diego County with a positive detection. (Read about the first San Diego County detection here.) The new detection was made in a residential citrus tree located in the Rancho Bernardo area of the city. The …

citrus

OLL Sweet Oranges Producing Pre-HLB Fruit Quality

Josh McGill Tip of the Week, Varieties

By Jude Grosser, Fred Gmitter and Maria Brenelli The new OLL (Orie and Louise Lee) series of sweet oranges (OLL-4, OLL-8 and OLL-20) are very high-quality processing sweet oranges that generally produce higher soluble solids and better juice color than Valencia. OLL trees are more vigorous than Valencia, and anecdotal evidence suggests they are slightly more HLB-tolerant than Valencia. Trees …

Trialing Tree Immunizations for HLB, Xylella

Josh McGill HLB Management, International, Research

Australia’s Hort Innovation has announced an $8.7 million investment to trial tree immunizations that protect Australia’s horticulture industries against the deadly huanglongbing (HLB) and Xylella diseases (including citrus variegated chlorosis). Hort Innovation is a grower-owned, not-for-profit research and development corporation for Australia’s horticulture industry. Hort Innovation Chief Executive Brett Fifield said the investment aims to safeguard key Australian horticulture industries by …

Natural Compounds Might Fight HLB

Josh McGill HLB Management, Research

The U.S. Department of Agriculture (USDA) has awarded Florida International University (FIU) scientists $500,000 to investigate natural compounds that could suppress or even eliminate the bacteria that causes HLB. FIU Institute of Environment researcher Kateel Shetty is leading the search for an antimicrobial compound that could help citrus growers. The FIU team’s theory is that if they can identify a …

Psyllids and HLB in Georgia Citrus

Josh McGill Georgia, Psyllids

When commercial citrus acreage started migrating north some years ago, the big question was: To what extent would Asian citrus psyllids (ACP) and HLB migrate with the crop? With citrus getting well established in South Georgia, the pest and disease are there, but not yet at devastating levels like in Florida. Johnathan Oliver, an assistant professor of fruit pathology with …

Trunk Injection for HLB: What You Need to Know

Josh McGill HLB Management

Some Florida citrus growers have recently started oxytetracycline hydrochloride (OTC-HCl) injection into tree trunks to help manage HLB. Other growers are considering it. Researcher Ute Albrecht offered a list of best practices for the product’s use during a Jan. 31 presentation in Immokalee. The presentation was made at the University of Florida Institute of Food and Agricultural Sciences Southwest Florida …

Trunk Injection Not a Silver Bullet for HLB

Josh McGill Diseases, HLB Management

Although trunk injection of oxytetracycline hydrochloride  (OTC-HCl) has received much recent press for its promise in managing HLB, there is still no silver bullet for the devastating disease. That was part of plant pathologist Ozgur Batuman’s message at a Dec. 10 seminar addressing HLB and other citrus diseases that may exacerbate HLB’s effects on trees. “There is no single effective …

CRDF Allocates Year-End Funds to HLB Research Projects

Josh McGill CRDF, HLB Management, Research

The Citrus Research and Development Foundation (CRDF) met for its December board meeting to discuss several topics before heading into the new year. One of the bigger areas of discussion was what to do with available uncommitted funds. “The board decided to fund work on several questions growers have regarding the use of bactericides inserted through systemic delivery devices and …

Guide Prepares California Growers for HLB Detection

Josh McGill California Corner, HLB Management, Regulation

California’s Citrus Pest and Disease Prevention Program (CPDPP) has developed a guide, Response for a Confirmed Huanglongbing Positive Detection in a Commercial Grove, to prepare growers for a finding of the disease. The guide is intended to educate growers about the California Department of Food and Agriculture’s (CDFA) huanglongbing action plan. The devastating citrus disease spread by the Asian citrus …

HLB Resistance Is Citrus Breeding Program’s Primary Focus

Josh McGill Breeding

Citrus breeding is conducted at different research facilities across Florida. But the objective remains the same for University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) breeders: Develop HLB-resistant citrus. That is the goal for Jose Chaparro, UF/IFAS associate professor in Gainesville. His research will impact citrus produced in the North Florida and South Georgia regions. “If you look …

Unraveling the Relationship Between the HLB Bacterium and Trees

Josh McGill HLB Management, Research

At the heart of the HLB threatening the Florida citrus industry is a complex exchange between the citrus tree and an insidious bacterium. University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) researchers continue to study the bacterium that causes HLB. They are learning more about how it works within the citrus tree in an effort to find viable …

Researchers Study Relative of HLB Pathogen

Josh McGill HLB Management, Research

Sometimes the most niche plant pathogen packs the greatest punch. Such is the case for the Florida citrus industry, which has seen a 70% decline in its orange production since the introduction of HLB in 2005. HLB is also known as citrus greening disease.  The bacteria Candidatus Liberibacter asiaticus cause this disease, which spreads via a flying insect. When the …

citrus production

Research to Help Organic Growers Fight HLB

Josh McGill Organic, Research

A grant from the U.S. Department of Agriculture’s Organic Agriculture Research and Extension Initiative (OREI) is intended to advance research to help organic citrus producers fight HLB.   The grant awards $2.03 million to a team of scientists from the University of Florida, Texas A&M University and The Organic Center. The Organic Center is a non-profit organization convening evidence-based science on the …