Study Discovers Citrus Greening Affects Roots Before Leaves

Although citrus greening enters trees through their leaves, University of Florida researchers have discovered that the deadly disease attacks roots long before the leaves show signs of damage — a finding that may help growers better care for trees while scientists work to find a cure.

“The role of root infection by insect-carried bacterial pathogens has been greatly underestimated,” said Evan Johnson, a research assistant scientist with UF/IFAS.

Johnson was the lead author of a scientific paper outlining the research published in the April issue of the journal Plant Pathology. He and his fellow team members — Jian Wu, a graduate student in soil and water science, researcher Diane Bright and Jim Graham, a professor of soil microbiology — are based at the UF/IFAS Citrus Research and Education Center in Lake Alfred.

Citrus greening first enters the tree via the Asian citrus psyllid, which sucks on leaf sap and leaves behind bacteria that spread through the tree. Johnson said the bacteria travel quickly to the roots, where they replicate, damage the root system and spread to the rest of the host tree’s canopy.

It was originally thought that the leaves and fruit were affected first, but the team’s research found that greening causes a loss of 30% to 50% of trees’ fibrous roots before symptoms are visible above ground.

“This early root loss means that the health of a citrus tree is severely compromised before the grower even knows it is infected,” Johnson said.

Experts say this research is significant in the fight against greening.

“Based on the work of Dr. Johnson and his colleagues, we now know how important roots are in the development of greening disease,” said Jackie Burns, director of the CREC. “We hope further investigations on the role of roots in this disease will lead to future management solutions that help growers remain productive until a permanent solution can be found.”

“We are still trying to determine how the bacteria are killing the roots,” Johnson said. “This finding suggests that growers should focus more effort on maintaining the health of the root system in relation to other soilborne pests and overall soil quality to maintain as much of the root system as possible.”

Johnson suggested that growers increase the acidity levels of irrigation water and soil to match the optimum pH for the rootstock (preliminary results show that this improves root density compared to untreated groves) and water more frequently for shorter periods. Those treatments are being studied by UF researchers in Lake Alfred and at the Southwest Florida Research and Education Center in Immokalee.

Topics: , ,

Leave a Reply

Citrus Stories
Fallen citrus fruit in wake of Irma
Citrus
October 12, 2017
Irma Rains Down on Florida Citrus Crop Estimate
Initial USDA forecast reflects the fruits of what was left behind by monster storm. Read More
A water-logged citrus grove in Southwest Florida following Irma
Citrus
October 10, 2017
Impressions from Irma Indelible on the Florida Farmscape [Slideshow]
Striking images from the field reveal not only the storm’s destructive nature, but also paths to recovery and reconstruction. Read More
Citrus
October 9, 2017
(We Won’t Back Down … ) Stand Your Ground for Agriculture
You don’t have to be a super hero, rock star, or award-winning scientist to aid farming. You can help by supporting professionalism in fields. Read More
Greenhouse structure damage at SWFREC in Immokalee
Citrus
October 6, 2017
Complications Persist as Florida Growers Pick up After Irma
Ground zero perspective reveals how citrus and vegetable producers are facing different, daunting challenges in wake of destructive storm. Read More
Growers boot up drone technology on the farm
Citrus
October 5, 2017
Are You a Precision Grower?
Gathering, analysis, and application still seems to be the best basic definition of precision agriculture. Read More
Greenhouse structures flattened by Irma at C&B Farms
Citrus
October 5, 2017
Hurricane Irma Toll on Florida Farming in the Billions
Preliminary damage estimates confirm storm’s ferocity. Read More
A sea of citrus fruit floating in floodwater after Irma
Citrus
October 5, 2017
Tips to Help Hurricane-Stressed Citrus Trees
Cleaning up damage and small doses of nutrition the fastest path to helping blocks bounce back. Read More
Citrus
October 4, 2017
Goodlatte Officially Introduces the Ag Guestworker Act
On Monday, Rep. Bob Goodlatte (R-VA) introduced his Agricultural Guestworker Act of 2017 bill, which would replace H-2A with an H-2C program. Rep. Goodlatte introduced the bill to the House Judiciary Committee, which he chairs. Read More
honeybees
Citrus
October 2, 2017
$10 Million for Honeybee Health
National Honey Board, Project Apis.m investing in pollinator research. Read More
Swamped citrus in Southwest Florida
Citrus
October 2, 2017
Perseverance a Priority for Florida Farmers Post-Irma
Commissioner of Agriculture Adam Putnam heartened by the strides being made by growers around the state as they begin to recover from the hurricane. Read More
cash money in hand
Citrus
October 2, 2017
$18 Million in Grants Available for Value-Added Producers
Farmers in need of planning or working capital funds to move their ideas forward encouraged to check out program. Read More
Asian citrus psyllid closeup
Insect & Disease Update
September 28, 2017
Attention to Citrus Psyllid Control Critical After Hurricane Irma
Flushing trees will give HLB vector perfect breeding ground. Read More
Field of carinata
Citrus
September 27, 2017
Research on Jet Fuel Cover Crop Ready for Takeoff
Scientists seeking to find if carinata can sustainably feed future renewable energy demands. Read More
Citrus
September 27, 2017
Agriculture Offers Rare Opportunity for Bipartisan Action
A running theme from agricultural-friendly politicians speaking at the United Fresh Produce Association's Washington Conference was the need for a bipartisan approach to agriculture and immigration. Read More
Citrus
September 27, 2017
Will H-2A Become H-2C? Find Out What the New Bill Proposes
Rep. Bob Goodlatte (R VA) is re-introducing a bill that aims to replace H-2A. Here are some of the ways it will differ from the current program. Read More
The Latest
Citrus
October 18, 2017
How to Keep Track of Climate Change
Use cool tools to find out how your production methods may change in the future, how much your area is at risk, and how to limit your own impact on the climate. Read More
Citrus
October 17, 2017
USDA Issues Disaster Declaration for Hur…
Operators in designated counties eligible for emergency assistance. Read More
Citrus
October 16, 2017
Wrath of Hurricane Irma’s Rainfall…
Report says storm dropped enough gallons of water on Florida’s St. Johns River Water Management District to swamp 6.7 million football fields. Read More
Citrus
October 12, 2017
Irma Rains Down on Florida Citrus Crop E…
Initial USDA forecast reflects the fruits of what was left behind by monster storm. Read More
Citrus
October 10, 2017
Impressions from Irma Indelible on the F…
Striking images from the field reveal not only the storm’s destructive nature, but also paths to recovery and reconstruction. Read More
Citrus
October 9, 2017
(We Won’t Back Down … ) Stan…
You don’t have to be a super hero, rock star, or award-winning scientist to aid farming. You can help by supporting professionalism in fields. Read More
Citrus
October 6, 2017
Complications Persist as Florida Growers…
Ground zero perspective reveals how citrus and vegetable producers are facing different, daunting challenges in wake of destructive storm. Read More
Citrus
October 5, 2017
Are You a Precision Grower?
Gathering, analysis, and application still seems to be the best basic definition of precision agriculture. Read More
Citrus
October 5, 2017
Hurricane Irma Toll on Florida Farming i…
Preliminary damage estimates confirm storm’s ferocity. Read More
Citrus
October 5, 2017
Tips to Help Hurricane-Stressed Citrus T…
Cleaning up damage and small doses of nutrition the fastest path to helping blocks bounce back. Read More
Citrus
October 4, 2017
Goodlatte Officially Introduces the Ag G…
On Monday, Rep. Bob Goodlatte (R-VA) introduced his Agricultural Guestworker Act of 2017 bill, which would replace H-2A with an H-2C program. Rep. Goodlatte introduced the bill to the House Judiciary Committee, which he chairs. Read More
Citrus
October 2, 2017
$10 Million for Honeybee Health
National Honey Board, Project Apis.m investing in pollinator research. Read More
Citrus
October 2, 2017
Perseverance a Priority for Florida Farm…
Commissioner of Agriculture Adam Putnam heartened by the strides being made by growers around the state as they begin to recover from the hurricane. Read More
Citrus
October 2, 2017
$18 Million in Grants Available for Valu…
Farmers in need of planning or working capital funds to move their ideas forward encouraged to check out program. Read More
Citrus
September 27, 2017
Research on Jet Fuel Cover Crop Ready fo…
Scientists seeking to find if carinata can sustainably feed future renewable energy demands. Read More
Citrus
September 27, 2017
Agriculture Offers Rare Opportunity for …
A running theme from agricultural-friendly politicians speaking at the United Fresh Produce Association's Washington Conference was the need for a bipartisan approach to agriculture and immigration. Read More
Citrus
September 27, 2017
Will H-2A Become H-2C? Find Out What the…
Rep. Bob Goodlatte (R VA) is re-introducing a bill that aims to replace H-2A. Here are some of the ways it will differ from the current program. Read More
Citrus
September 26, 2017
Rise of Agricultural Automation Drives I…
The International Forum of Agricultural Robots aims to provide links to farming’s future. Read More